• Facebook - Black Circle
  • YouTube - Black Circle

30681 Wixom Rd. Wixom, MI 48393   P: 888-66-FLOOR

6409 Fayetteville Rd. Durham, NC 27713   P: 919-588-0224

2019 Foster Specialty Floors. All Rights Reserved

POSITION STATEMENTS

 

The following MFMA position statements were created to assist in the education of maple athletic flooring. They are created for those who do not have a detailed knowledge of the construction and/or post installation use and maintenance of athletic floors. Information contained herein is based on best industry practices and knowledge, however the MFMA, its members and employees, do not warrant the information contained herein as proper under all conditions. The MFMA reserves the right to revise these position statements as necessary. Questions concerning information contained in these position statements should be directed to Foster Specialty Floors. Please call Fosters at (888) 66-FLOOR or EMAIL us here.

ADA PRESS RELEASE

Proper installation of raised sport floors, especially in retrofit projects, can have implications for the sport floor contractor where vertical rises exceed ½" in public entrances. MFMA recommends in these instances the sport floor contractor confirms in writing with the architect, design professional or owner these areas meet Federal ADA, state and local access codes before installation begins.

It is the responsibility of the architect, design professional or owner to ensure the project meet Federal ADA, state and local access codes.

 
 

BLEACHER BLOCKING

MFMA refers all inquiries concerning subfloor bleacher blocking requirements to the individual flooring system manufacturer and the specified bleacher manufacturer. Variances in bleacher system design, loading, total weight, and operation make uniform specifications for subfloor blocking impossible.

CHATTER MARKS

Chatter marks, in a very moderate form, are fairly common in new maple installations where drum or riding sanders are used in the flooring surface sanding process.

 

MFMA has no written policy or specification regarding the appearance or frequency of chatter marks in our flooring installations. Generally speaking, minor chatter marks are apparent in scattered locations on most flooring installations. They are considered excessive if close-up inspection yields noticeable uneven or gouged areas of the flooring.

 

There can be a number of causes of chatter marks. The most common occurrence in the maple itself results from the use of drum or riding sanders on a surface with a degree of built-in "give." These are very different from chatter marks between layers of finish, which are typically seen when lighting is reduced and angled reflections are observed.

 

Between-coat buffing is desirable to ensure proper adhesion of successive coats of finish, and in fact is required under certain finish manufacturer warranties. Flooring appearance in these cases is akin to a fresh wax job on a black automobile -- when viewed at a specific angle under specific lighting conditions, marks are visible.

 

Chatter marks of this type are not damaging to the surface, nor will the marks impair the playability or performance of the system. Typically, the marks will soon begin to disappear as the oil-modified finish on the floor ambers with age.

 

The pace of ambering varies from product to product, but most color changes will take place between six months to fifteen months following the initial application. However, water-based finishes do not amber over time and if you think chatter marks are present, check the severity and contact your flooring installer.​

 
 
 
 

CONCRETE PADS UNDER FIXED BLEACHER SYSTEM

The placement of permanent concrete pads under large fixed bleacher banks has become more common in an effort to reduce installation costs in an area of a gymnasium floor that gets little use. The transition between such concrete pads and the adjacent wood floor often consists of a metal transition plate.

 

The use of concrete pads to support the bleachers in the closed position, and the installation of a transition plate to the wood floor system is, in many cases, an unworkable design for a motor-driven bleacher system — particularly a large bleacher system.

 

It is our opinion that the best solution to minimize potential difficulties that may occur with the combination of a resilient floor system and large bleacher banks is to install sufficient bleacher blocking under the location where the bleachers will rest in the closed position, and to extend the maple surface completely under the bleacher banks. The installation of solid wood blocking under the bleacher may be necessary to reduce or eliminate the deflection associated with heavy bleacher movement over a resilient wood flooring system. If cost is a concern, consider using a lower grade of flooring in the areas under the bleacher banks.

 

MFMA refers all inquiries concerning subfloor bleacher blocking requirements to the individual flooring system manufacturer and the specified bleacher manufacturer. Variances in bleacher system design, loading, total weight, and operation make uniform specifications for subfloor blocking impossible.

 ​

CONCRETE SLAB CONFIGURATION

DEERFIELD, IL - Concrete slab configuration is very important in the success of a new maple floor installation. Placing a below-slab vapor barrier directly beneath the concrete slab is proper and typical. Placing any type of fill material between the below-slab vapor barrier and the concrete slab may cause moisture-related problems with the finished maple surface.

 

MFMA requires the general contractor to provide a concrete slab troweled smooth and flat to a tolerance of 1/8” in a 10’ radius, subject to the approval of the FSF wood flooring contractor. By placing sand between the vapor barrier and the slab, a flatter concrete slab with less initial curling can be produced. However, this new configuration allows the sand to possibly act like a sponge -- trapping moisture within the sand layer during the concrete pour. Over time, trapped moisture can migrate up through the concrete slab and cause moisture-related difficulties with subfloor components and the finished wood flooring surface.

 

The only MFMA recognized method for reading concrete moisture levels within a slab is by testing its relative humidity. Please refer to the instructions of the manufacturer’s relative humidity test kit for complete details on how to administer the test correctly. MFMA recommends the relative humidity level for a concrete slab for anon-glue-down maple floor system be 85% or lower and for glue down systems the concrete slab relative humidity level should be 75% or lower before installation. For concrete relative humidity conditions above MFMA's recommendation consult your FSF Sport Floor Contractor.

CONCRETE SLAB FITNESS

MFMA requires the general contractor to provide a concrete slab troweled smooth and flat to a tolerance of 1/8" in a 10' radius, subject to the approval of the FSF wood flooring contractor.

 

Labor and materials necessary to put the concrete slab in acceptable condition, (high areas ground down and low areas filled with appropriate leveling compounds) are the responsibility of the general contractor or concrete subcontractor.

 

No pea gravel, river gravel or slag aggregate can be allowed in a gymnasium concrete slab. The concrete strength range at the time of wood flooring installation should be between 3,000 P.S.I. and 3,500 P.S.I.

FSF recommends the following procedures to be used by the general contractor or concrete subcontractor to provide the appropriate slab flatness requirement:

 

  • Plot a 5' grid on the slab surface.

 

  • Using a 10' straight edge, move it perpendicular to the plotted grid in both directions to identify all areas requiring correction. (Note: The use of a transit or laser alone does not include measurements between the grid points.)

 

  • All high spots should be ground level. Fill low areas with appropriate leveling compound. The fill must not become brittle, crack or lose bonding to the concrete slab. Fill must not be affected by loads applied to resilient pads if present. In anchored system applications, the fill must provide the required P.S.I. strength and allow anchoring without breaking or spawling when pins are installed. This is the responsibility of the general contractor or concrete subcontractor.

CONCRETE SLAB MOISTURE CONTENT

Installation of an MFMA flooring system shall not commence until the subfloor is determined to be "dry" by industry standard testing procedures. MFMA does not recommend testing for concrete moisture content within 60 days of pour. The required vapor barrier or under-slab membrane will likely increase slab drying times. Some factors affecting the concrete slab ‘s drying time include:

 

  • Slab thickness

  • Surface applied treatments

  • Type of construction

  • Concrete formulation

  • Location of the building

  • Climatic conditions

  • Power troweling

 

When conducting slab moisture testing, follow the manufacturer’s recommendation on the number of tests that should be performed - regardless of the age of the slab, document all tests. If the test(s) indicate a wet slab, delay installations of the maple system until specified conditions are met.

 

It is the general contractors’ responsibility to provide a dry concrete slab within MFMA standards for moisture content and flatness. The flooring contractor shall verify slab conditions prior to the commencement of any maple flooring system installation to ensure compliance with flooring manufacturer specifications.

 

The only MFMA recognized method for reading concrete moisture levels within a slab is by testing its relative humidity. Please refer to the instructions of the manufacturer’s relative humidity test kit for complete details on how to administer the test correctly. MFMA recommends the relative humidity level for a concrete slab for anon-glue-down maple floor system be 85% or lower and for glue down systems the concrete slab relative humidity level should be 75% or lower before installation. For concrete relative humidity conditions above MFMA’s recommendation consult your FSF Sport Floor Contractor.

 

Concrete Relative Humidity Test

  • Relative Humidity Test (In-Situ Probe Test)Use a prepackaged relative humidity testing kit (must be compliant with the most recent ASTM F2170) and follow the manufacturer's instructions. This test method involves measuring relative humidity levels inside of the concrete slab.

 

Pre-Tests

The following can be administered as pre-tests for testing the moisture content of a concrete slab but should not be used to confirm a concrete slab has dried to acceptable levels:

  • Polyethylene Film TestTape a 2' x 2' square of 6 mil clear polyethylene film flat to the slab, sealing all edges with moisture resistant tape. Suspend a 250-375 watt heat lamp 2' above the plastic film. After 24 hours, check the film - if no condensation or "clouding" develops on the underside of the polyethylene, the test area shall be considered dry enough to test the concrete slab’s relative humidity.

  • Calcium Chloride TestUse a prepackaged calcium chloride test (widely available) and follow the manufacturer's instructions. The Calcium Chloride Test measures the quantity of moisture passing through a concrete floor. This measurement is stated as pounds of moisture over a 1,000 sq. ft. area during a 24-hour period. An acceptable level is 4.5 lbs. or less.

  • Electronic Concrete Moisture MetersDue to the different types of electronic concrete moisture meters on the market, MFMA recommends following the manufacturer’s instructions for proper on-site testing procedures.

CUPPING AND CROWNING

Cupping and crowning are two unfortunate results of excessive moisture in maple flooring.

 

All moisture content increases cause wood products to expand. Due to the cellular structure of flat-sawn maple flooring, expansion takes place primarily across the width of each strip. When flooring strips in a maple system take on enough moisture to expand and eliminate all available horizontal expansion space, individual boards will expand upward at the edges causing the surface condition commonly known as cupping. Cupping is caused by a moisture imbalance through the thickness of the maple — moisture contents in each strip of flooring are higher at the bottom than on the surface.

 

If cupping is severe enough, a condition known as "compression set" can occur. Compression set is caused by severe expansion pressure from excessive moisture causing individual boards to crush each other. Individual cells on the edges of each maple strip are permanently deformed or crushed, leaving excessive cracks and ragged edges when the material returns to its normal moisture content.

 

Crowning is the opposite of cupping. The center of each flooring strip is higher than its edges. Moisture imbalance is sometimes the cause of crowning if excessive moisture is introduced on the top of the floor due to roof leaks, spills or improper maintenance procedures. However, crowning is more commonly caused by sanding a cupped floor before the moisture content in the maple returns to a uniform and normal condition top to bottom.

 

Sanding while the flooring is still cupped will result in the loss of flooring material on the edges of each board. Once all excess moisture works its way out of the flooring materials, the maple will return to a flat condition - except where the original edges of the strips were sanded off, leaving voids at the edges of each flooring row.

 

Some slight cupping and/or crowning may occur naturally and is acceptable. The "bark" side of a maple log will shrink/swell more than the center of a maple log, and this minor expansion/contraction variation is more noticeable in areas of the country that experience significant seasonal moisture content changes and on floors containing wider face-width maple strips.

 

MFMA recommends maintaining indoor temperatures between 55 and 75 degrees and indoor relative humidities between 35 percent and 50 percent year round. If the flooring materials are properly acclimated, a 15 percent fluctuation in indoor relative humidity will not adversely affect the maple. Excessive shrinkage and/or expansion may occur with indoor relative humidity variations in excess of 15 percent.

DEAD SPOTS

Cupping and crowning are two unfortunate results of excessive moisture in maple flooring.

 

All moisture content increases cause wood products to expand. Due to the cellular structure of flat-sawn maple flooring, expansion takes place primarily across the width of each strip. When flooring strips in a maple system take on enough moisture to expand and eliminate all available horizontal expansion space, individual boards will expand upward at the edges causing the surface condition commonly known as cupping. Cupping is caused by a moisture imbalance through the thickness of the maple — moisture contents in each strip of flooring are higher at the bottom than on the surface.

 

If cupping is severe enough, a condition known as "compression set" can occur. Compression set is caused by severe expansion pressure from excessive moisture causing individual boards to crush each other. Individual cells on the edges of each maple strip are permanently deformed or crushed, leaving excessive cracks and ragged edges when the material returns to its normal moisture content.

 

Crowning is the opposite of cupping. The center of each flooring strip is higher than its edges. Moisture imbalance is sometimes the cause of crowning if excessive moisture is introduced on the top of the floor due to roof leaks, spills or improper maintenance procedures. However, crowning is more commonly caused by sanding a cupped floor before the moisture content in the maple returns to a uniform and normal condition top to bottom.

 

Sanding while the flooring is still cupped will result in the loss of flooring material on the edges of each board. Once all excess moisture works its way out of the flooring materials, the maple will return to a flat condition - except where the original edges of the strips were sanded off, leaving voids at the edges of each flooring row.

 

Some slight cupping and/or crowning may occur naturally and is acceptable. The "bark" side of a maple log will shrink/swell more than the center of a maple log, and this minor expansion/contraction variation is more noticeable in areas of the country that experience significant seasonal moisture content changes and on floors containing wider face-width maple strips.

 

MFMA recommends maintaining indoor temperatures between 55 and 75 degrees and indoor relative humidities between 35 percent and 50 percent year round. If the flooring materials are properly acclimated, a 15 percent fluctuation in indoor relative humidity will not adversely affect the maple. Excessive shrinkage and/or expansion may occur with indoor relative humidity variations in excess of 15 percent.

END JOINT SPACING IN RANDOM LENGTH STRIP AND FINGER JOINED STRIP FLOORS

End joints are the locations on a random length or finger-jointed strip wood floor where two pieces of flooring are joined together end to end by a single tongue and groove. Segment joints are the locations on a finger-jointed wood strip floor where two pieces of flooring are joined together end to end by a finger-joint. End joint spacing serves a very important structural function in athletic flooring systems that have non-continuous subfloor designs. Examples of such designs are "Sleeper" and "Fixed Sleeper" flooring systems without continuous subfloors. When end joints are installed closely together in adjoining rows, such concentrations of end joints can create weak spots in the system construction. MFMA recommends maintaining a minimum of 4 inches between end joints in adjoining rows when non-continuous subfloor designs are specified for athletic flooring installations.

 

End joint spacing does not serve a significant structural function in athletic flooring systems with continuous subfloor designs. However, proper spacing of end joints in adjoining rows of a maple athletic flooring system is important in order to maintain consistent performance characteristics across the playing surface. For this reason, MFMA also recommends maintaining the traditional minimum of 4 inches between end joints in adjoining rows when continuous subfloor designs are specified for athletic flooring installations.

 

Given the above recommendations, MFMA acknowledges that even the most conscientious installer may occasionally install flooring strips with end joints spaced less than 4 inches in adjoining rows on a typical flooring installation. Such occasional installation is by itself not a valid reason for rejection of an athletic flooring surface.

 
 
 
 
 
 
 
 
 

EXPANSION SPACING ("WASHER ROWS")

Wood is a hygroscopic material. When exposed to varying temperature and humidities, it will release or absorb moisture until it is at equilibrium with the surrounding atmosphere.

 

Maple floors in the United States experience moderate seasonal moisture content swings as a result of normal climate changes during the year. For example, in an average year, maple flooring in lower Michigan experiences a 3 percent to 4 percent variation in moisture content, depending on location. A 4 percent swing can translate just less than 1/32" of expansion/contraction for each 2 1/4" face-width board in a maple flooring system.

 

To ensure successful placement and performance, many contractors install intermediate expansion spaces at regular intervals across the surface to allow maple expansion as normal seasonal changes dictate. Intermediate expansion spacing (or "washer rows") is installed at the discretion of the flooring contractor based on flooring moisture contents at the time of installation and/or normal anticipated changes in moisture contents throughout the year. Although either 1/16" or 1/8" washers are commonly used, the 1/16" spacers require less movement of the flooring strips during expansion, and are less visually objectionable.

 

Please note that spacing and frequency of intermediate expansion spacing is directly related to the time of year that the flooring is installed, as well as the amount of acclimation time provided in the construction schedule. Until you have a firm construction timetable from the General Contractor, it is difficult to calculate the precise amount of expansion/contraction spacing that will need to be provided.

EXPANSION VOIDS

Expansion voids are areas in a maple sports flooring system where no flooring or subflooring components are installed, specifically to provide space for system movement. Expansion voids are usually found at the perimeter of a floor and at all vertical obstructions (bleacher anchors, volleyball inserts, floor electrical outlets and audio box hookups, etc.) within the borders of the floor.

 

Fosters' sports flooring systems are generally designed in either "fixed" or "floating" configurations. "Fixed" flooring systems are typically specified in locations where system movement is not anticipated or desired, and "floating" floor systems are typically specified in installations where system movement is anticipated.

 

All MFMA manufacturers have detailed specifications which call for installation of expansion voids at the perimeter and at all vertical obstructions on certain of their flooring systems. The installation of expansion voids at the system perimeter and at all vertical obstructions is required in most "floating" floor system specifications.

 

As a general rule, FSF recommends that no fixtures, equipment or bleachers be anchored through "floating" maple sports flooring systems into the concrete subfloor without first cutting surface maple and wood subfloor components away from lag bases and permanent in-floor fixtures to provide proper space for normal system movement.

 

"Fixed" systems such as the generic Nail-in-Channel and Channel and Clip floors are designed to hold the flooring tightly in place, restraining the system from movement. Installation of expansion voids at the perimeter and at vertical obstructions is not usually required with these system configurations.

Consistent effort must be given to keep all expansion voids clean and free of debris. Regular attention to perimeter voids and floor insert locations will ensure flooring system movement as the system was designed. Buckling, warping and rolling of flooring components can occur when expansion voids are clogged with debris — impeding the system from free movement it was designed to accommodate.

MFMA and all of its member manufacturers have published specifications that prescribe optimum temperature and humidity ranges to ensure satisfactory performance and reduce the likelihood that any bind-up of components will ever occur on a maple floor installed with proper provision for system movement.

 

FSF recommends maintaining indoor temperatures between 55 and 75 degrees and indoor relative humidities between 35 percent and 50 percent year round. If the flooring materials are properly acclimated, a 15 percent fluctuation in indoor relative humidity will not adversely affect the maple. Excessive shrinkage and/or expansion may occur with indoor relative humidity variations in excess of 15 percent, and variations of this magnitude may create difficulties with vertical obstructions in some "floating" flooring systems.

 
 

Ff/Fl NUMBERS AND CONCRETE SLAB FLATNESS

The American Concrete Institute has adopted F-Numbers as its standard for the specification and measurement of concrete slab flatness and levelness.

 

Ff, or "flatness F-Number," defines the maximum floor curvature allowed over 24" (600 mm) computed on the basis of successive 12" (300 mm) elevation differentials. Fl, or "levelness F-Number," defines the relative conformity of the floor surface to a horizontal plane as measured over a 10' (3.03m) distance. The higher the F-Numbers, the more level or flat the slab.

 

MFMA does not acknowledge the use of F-Numbers to measure levelness/flatness tolerances in gymnasium slab applications. If an F-Number is specified for flatness, it must be at least the equivalent of MFMA's standard 1/8" in 10' radius tolerance, and the following conditions must be adhered to in order to meet MFMA's standard slab specification:
 

  • The F-Number measurement must be taken two (2) weeks prior to the maple floor installation.

  • The measurement process must include all construction joints over the entire concrete slab.

  • The FSF flooring installer must be present during the entire measurement process.

 

If the above conditions are not met during all Ff/Fl Number measurements, MFMA does not recommend the acceptance of any Ff/Fl test. MFMA's standard 1/8" in 10' radius flatness specification should be enforced.

 
 

FINISH AMBERING

Urethane oil finishes (the type most commonly specified for maple basketball, multipurpose and stage floors) as a group have a tendency to amber over time. The timing and degree of the ambering vary by product, but typically the greatest color change in the finish takes place between the sixth month and the end of the first full year of service.

 

In a repair situation, replacement boards will appear generally lighter in color than surrounding existing boards due to the ambering affect of the existing oil finish. The degree of variance is a function of the age and number of coats of finish on the original flooring. Color variations in the finish should be expected on a repaired floor immediately after repairs are completed. Most repair areas begin to blend in with surrounding flooring after several months and over time become imperceptible to the untrained eye.  As a rule MFMA does not recommend tinting a repaired area to match existing floor coloring, and does not recommend staining maple flooring under any circumstances.

FINISH PEELING/CHIPPING

Finish peeling and/or chipping, in a very moderate form, occasionally occurs in new maple installations that experience large swings in humidity levels. This condition most often develops over painted areas of the maple surface.

 

MFMA has no written policy or specification regarding the appearance or frequency of finish peeling and/or chipping in MFMA flooring installations. Finish peeling and/or chipping can be a result of expansion/contraction of the flooring system due to seasonal moisture level changes, which causes fractures in the finish in painted areas as maple flooring adjusts to drier indoor conditions during the heating season.

 

The "elastic" properties of many surface finishes are commonly restricted by application over less "elastic" game line paints. During the first heating season, a new maple floor will typically contract more than in subsequent years under the same environmental conditions. USDA performance data confirms this physical characteristic with all hardwood species.

Assuming drier than average conditions exist in a facility during the first heating season, above-average shrinkage may result in some paint fracture over maple joints and subsequent peeling or chipping of surface finish in these areas, regardless of the application methods used with the floor sealer, game marking paint and finish. With the use of tape or decals, floor finish may experience similar conditions.

 

Maple flooring adjusts to its environment over its lifetime. Typically, the most expansion/contraction is experienced in the first 18-24 months of a floor life. The Maple Flooring Manufacturers Association (MFMA) recommends maintaining indoor relative humidities between 35 percent and 50 percent, and air temperatures between 55 degrees and 75 degrees year-round.

By limiting wide swings in atmospheric conditions inside the facility, flooring owners and facility managers can reduce the expansion and contraction of the flooring system. If flooring materials are properly acclimated, a 15 percent fluctuation in indoor relative humidity will not adversely affect the maple. Excessive shrinkage and/or expansion may occur with indoor relative humidity variations in excess of 15 percent.

 

In buildings where air conditioning or humidification/dehumidification equipment is not available, many facility managers make use of circulating or venting fans. Other facilities have vent windows or corridor doors available to open as needed to improve air circulation.

 

Facilities without adequate HVAC equipment to regulate the indoor atmosphere, or those facilities that are "closed up" with no ventilation for long periods of time (summer breaks) are more likely to develop flooring problems directly related to environment. Floor finish peeling and/or chipping as a result of expansion/contraction cycles can be minimized by carefully monitoring and adjusting the indoor environment in the facility, particularly during the first year after installation.

 
 

FLOOR PENETRATIONS

All MFMA manufacturers have detailed specifications that call for installation of expansion voids at the perimeter and at all vertical obstructions on most types of their flooring systems. The installation of expansion voids at the system perimeter and at all vertical obstructions is required in most floor system specifications. As a general rule, MFMA recommends that no electric fixtures, public address equipment outlets, sports equipment bases or bleacher banks be anchored through maple sports flooring systems directly into the concrete subfloor without first cutting surface maple and wood subfloor components away from lag bases and all other permanent in-floor fixtures to provide proper space for normal anticipated system movement. Installation of a 1-1/2" - 2" expansion void at the perimeter and at vertical obstructions is required for most floor system configurations.

 

Systems such as the generic Channel and Clip floors are designed to hold the flooring tightly in place, restraining the system from movement. Installation of a 1-1/2" - 2" expansion void at the perimeter and at vertical obstructions is not usually required with these system configurations.

 

FLOOR SQUEAKS

Flooring squeaks and "pops" are typically the result of the interplay between the tongue and groove in adjacent rows of strip flooring. Tongue and groove material rubs together during facility use, causing squeaking and popping sounds during either the loading or unloading phases of activity on the surface.

 

Maple flooring is a hygroscopic material. When exposed to varying temperatures and humidities, it will release or absorb moisture until it is at equilibrium with the surrounding atmosphere. This environmental interaction will cause individual flooring strips to expand or contract.

 

Regular seasonal flooring system movement combined with facility use at certain times during the year can result in the development of squeaks and "pops" in scattered locations when the match between tongue and groove in adjacent strips changes.

 

It is impossible to guarantee that any wood floor system will not develop squeaks or "pops" as a result of normal seasonal expansion and contraction. Due to resiliency requirements and multi-layer subfloor configurations, some systems tend to develop squeaks and "pops" more consistently at certain times of the year than other systems. Expansion/contraction cycles and resulting squeaking/popping difficulties can be minimized by maintaining a consistent indoor environment.

 

MFMA recommends maintaining air temperatures between 55 and 75 degrees, and indoor relative humidities between 35 and 50 percent year round. If flooring materials are properly acclimated, a 15 percent fluctuation in indoor relative humidity will not adversely affect the maple. Excessive shrinkage and/or expansion (and resulting squeaks/pops) may develop with indoor relative humidity variations in excess of 15 percent.

 

Remedies for noisy floors include the application of talcum powder in areas of occasional squeaks or pops, or the installation of additional mechanical fasteners (face-applied and plugged) in areas of persistent squeaks. The latter remedy may not be an option on certain floating floor systems.

 

HARD MAPLE & SOFT MAPLE

"Hard maple" is the common term for two species of maple trees: Sugar Maple (Acer saccharum) and Black Maple (Acer nigrum). Hard maple is commonly used in the manufacture of flooring, furniture, cabinets, billiard cues and other finished wood products. "Soft maple" is the common term for four species of maple trees: Silver maple (Acer saccharinum), Red maple (Acer rebrum), Boxelder (Acer negundo) and Bigleaf maple (Acer macrophyllum). Soft maple is commonly used for railroad crossties, boxes, pallets, crates, furniture, veneer, wooden ware and novelties. The flesh of soft maple trees -- in particular silver and red maple -- resembles that of hard maple, but is not as heavy, hard or strong.

 

All MFMA maple flooring is manufactured exclusively from Sugar Maple (Acer saccharum). This hardwood is the best type of maple for flooring due to the unique characteristics of this wood species. Characteristics that make Acer saccharum perfect for FSF flooring include fine and uniform texture, straight grain, resistance to shock, hardness and strength, resistance to dents and scratches, and stiffness.

 

For additional detailed information, consult the following sources:

 

  • Wood Handbook: Wood as an Engineering Material; U.S.D.A., 1999

  • U.S.D.A. Forest Products Laboratory General Technical Report FPL-GTR-113

  • U.S. Forest Products Society Catalogue Number 7269

  • U.S. Forest Products Society

  • U.S. Department of Agriculture Forest Products Laboratory, Madison, Wisconsin

 
 

HUMIDITY AND ENVIRONMENTAL RECOMMENDATIONS

MFMA recommends maintaining indoor relative humidities between 35 percent and 50 percent, and air temperatures between 55 degrees and 75 degrees year-round. By limiting wide swings in atmospheric conditions inside the facility, you will reduce the expansion and contraction of the flooring system. If flooring materials are properly acclimated, a 15 percent fluctuation in indoor relative humidity will not adversely affect the maple. Excessive shrinkage and/or expansion may occur with indoor relative humidity variations in excess of 15 percent.

 

In buildings where air conditioning is not available, many facility managers make use of circulating or venting fans. Other facilities have vent windows or corridor doors available to open as needed to improve air circulation. Facilities without adequate HVAC equipment to regulate the indoor atmosphere, or those facilities that are "closed up" with no ventilation for long periods of time (summer breaks) are more likely to develop flooring problems directly related to environment.

MOISTURE BARRIERS

Adequate moisture/vapor protection below on-grade maple flooring systems is essential to insuring problem-free installations. Typical floor system constructions incorporate two moisture barriers; one placed immediately below the concrete slab and the other placed directly on the concrete surface, immediately below the floor system. All MFMA (Maple Flooring Manufacturers Association) milling members recommend a damproofing membrane (under-the-slab moisture barrier) and require a surface vapor barrier (above-the-slab vapor barrier) to insure proper protection from moisture infiltration.

 

Under-the-slab moisture barriers -- Concrete subfloors shall have an adequate moisture barrier beneath and at the perimeter of the slab. These barriers must be chosen on the basis of the project site, building construction, soil type, etc., and shall be selected and specified by the project architect/engineer.

 

Above-the-slab vapor barrier -- shall be incorporated into maple flooring systems in addition to any specific the specified under-slab moisture barrier. Commonly specified surface vapor barriers include; seam-sealed polyethylene film and/or seam-sealed closed-cell polyethylene foam underlayment. In parquet systems utilizing adhesives adhered directly to the concrete, an above-the-slab vapor barrier is not applicable.

 

In practice, even after recommended drying time, occasional residual moisture may remain. Surface vapor barriers may assist in preventing the ill effects of undetected moisture. The principal purpose of above-the-slab vapor barrier is for dew point condensation related to slab temperature and environmental conditions. Migration of this moisture into flooring system materials may result in various moisture related problems, e.g., cupping, compression ridging and, in more extreme situations, buckling, mold/mildew, etc., even permanent irreparable damage. These barriers are typically recommended by the specified floor system manufacturer and shall be specified by the project architect.

NOTES:

 

  • Follow  MFMA milling manufacturer's guidelines for proper surface vapor protection.

  • MFMA does not endorse "below-grade" maple systems installations without the inclusion of adequate moisture protection.

MOISTURE INFILTRATION

Wood flooring may have different issues that may arise after moisture infiltration has occurred. Examples of moisture infiltration would include roof leaks, large spills, burst pipe, etc. The following is a list of issues that have frequently occurred.
 

  • Compression Set and Associated Shrinkage

    • Moisture infiltration may cause excessive shrinkage gaps between flooring strips that are commonly larger than normal seasonal shrinkage gaps after the wood returns to its normal moisture content range.

  • Cupping and/or Crowning

    • Cupping and/or crowning may take place from moisture infiltration due to expansion pressure from the flooring strips taking in excessive moisture.

  • Flooring Issues

    • Moisture infiltration may affect the integrity of the flooring and the deterioration of the flooring fasteners.

    • The most common affect on flooring from moisture infiltration is in the form of splits and end checks.

  • Finish Issues

    • Excessive expansion and contraction of the flooring strips may cause bonding issues of the floor finish, game lines and logos.

  • Mold and Dry Rot

    • Mold and dry rot on or below flooring strips may be a symptom of prolonged exposure to moisture.

    • Contact your local health officials for local ordinance on proper procedures when dealing with mold.

  • Continued Performance

    • The flooring manufacturer and installing contractor cannot guarantee that floors and floor systems affected by moisture will perform as originally designed.

    • Maple wood floors that have been exposed to moisture infiltration may have ongoing performance issues, which include, but not limited to, dead spots, fractured or splintering boards, and/or uniformity concerns.

 
 
 
 

MULTIPLE SPORT GAMELINES

Maple floors with multiple sport games lines should have one main sport with consistent solid game lines. All sports game lines and solid painted lines should be broken and spaced from the main sport’s game lines (Example A). Sport game lines that intersect large solid painted areas can be installed using 2” wide shadow-bordered lines with ¼” wide borders (Example B). The ¼” wide borders should lie within the 2” wide line.

MFMA does not recommend the use of masking, construction, electrical, duct or adhesive tape to mark temporary court boundaries on the surface of a finished maple floor. It is quite likely that the tape, when removed, will peel away layers of the floor’s surface finish. Most tapes promoted for temporary markings have a different coefficient of friction than finishes applied to the maple playing surface, and can impact a person’s ability to start, stop and pivot. Removing the surface paint/finish and exposing the maple can result in additional chipping and peeling of the remaining paint/finish in adjacent areas.

In addition, most commonly available tapes contain adhesive resins that can etch or stain the floor finish or even the maple flooring below the temporary markings.

PAINTED LINES, LOGOS AND BORDERS

Numerous brands of paint are successfully used on hardwood sports floors for game line and graphics applications. Brands of paint and compatible gymnasium floor finishes differ between flooring contractors based on their experience and preference of particular product applications.

 

Regardless of selected paints, only gymnasium floor finishes included in the Maple Flooring Manufacturers Association list of approved finishes should be used on MFMA floors.

 

Sound paint and finish adhesion relies on compatibility, necessary cure time and proper abrasion before applying added coats of paint or finish.

 

Most paints are suitably cured in 24 hours when exposed to moderate temperature and humidity. However, some paints such as custom colors require highly pigmented formulas to achieve desired shades thus requiring considerably longer curing time to acquire sound bonding with the next layer of paint or finish.

 

The above are general guidelines. It is imperative to always follow the finish manufacturers’ most current recommendations for finish and paint applications.

 
 
 

PANELIZATION

"Panelization" is a condition where localized excessive cracks develop between some strip flooring boards while adjacent boards remain tightly bonded together with no apparent separations. "Panelization" (or "sidebonding") is definitely not a new problem. It has, however, gained increasing attention as new EPA V.O.C. regulations have begun to affect the availability of traditional oil-based floor finishing products in many areas of the country.

 

While the development of "panelization" is certainly not limited to one brand of finish or to one particular subfloor design, the problem has been most closely associated with the use of water-based sealers and finishes on raw (untreated) maple strip flooring in areas of the country that experience distinctly different seasonal moisture conditions.

 

MFMA cautions installers and end-users that the use of some water-based finishes has produced a sidebonding effect that can result in localized excessive and irregular separations ("panelization") between maple flooring strips. We strongly recommend that end-users, project architects and specifiers consult with their flooring installer and finish manufacturer to obtain approved procedures for sealing and finishing a raw maple strip floor with water-based products.

 

PHYSICAL PROPERTIES AND CHARACTERISTICS

Type of Wood: Sugar maple / hard

Specific Gravity: .56 - .63

Modulus of Rupture (p.s.i.): 9400 - 15800

Modulus of Elasticity (million p.s.i.): 1.65 - 1.88

Work to Maximum Load (inch -lb / cu. in.): 13.3 - 16.5

Impact Bending — height of drop causing complete failure (in.): 40 - 39

Compression Parallel to Grain — maximum crushing strength (p.s.i.): 4020 - 7830

Compression Perpendicular to Grain — fiber stress at proportional limit (p.s.i.): 640 - 1479

Shear Parallel to Grain — maximum shearing strength (p.s.i.): 1460 - 2330

Side Hardness —load perpendicular to grain (lb.): 970 - 1450

Relative Hardness (ranked by the Janka hardness rating): 1450
12% harder than Northern Red Oak.

Relative Stability (ranked by dimensional change coefficient): .00353
4% more stable than Northern Red Oak.

Color: Heartwood is creamy white to light reddish brown; sapwood is pale to creamy white.

Durability: Dense, strong, tough, stiff, excellent shock resistance, markedly wear resistant.

Workability: Density makes it very difficult to saw; sands satisfactorily. Nailing: fair resistance to splitting; good holding ability. Finishing: takes neutral finish well; does not stain uniformly.

Flame Spread Index (ASTM-E84): 104

Smoke Developed Index (S.D.I): 157

PLYOMETRICS DOTS AND AGILITY LADDERS

The use of plyometric exercises is becoming increasingly popular with plyometric dots and agility ladders being the most requested game line applications.  MFMA has provided the following recommendations for applying plyometric dots and agility ladders to maple floors.

MFMA does not recommend the use of masking, construction, electrical, duct or adhesive tape to mark temporary markings on the surface of a finished maple floor.  It is quite likely that the tape, when removed, will peel away layers of the floor’s surface finish.  Removing the surface paint/finish and exposing the maple can result in additional chipping and peeling of the remaining paint/finish in adjacent areas.

Most tapes promoted for temporary markings have a different coefficient of friction than finishes applied to the maple playing surface, and can impact a person’s ability to start, stop and pivot. 


In addition, most commonly available tapes contain adhesive resins that can etch or stain the floor finish or even the maple flooring below the temporary markings.

 
 

POLY BALLS

“Poly Balls” occasionally occur in new maple installations or during resurfacing or recoating of existing maple floors coated with oil based floor finish. The finish collects between flooring strips and cures at a much slower rate. With some new low-VOC oil-modified finishes the cure time has increased. Solvent-based finishes rely on exposure to oxygen to cure the film. A situation may occur when the finish is applied penetrates between the flooring strips.

 

Once the finish gets in between the flooring strips, it becomes more difficult for oxygen to react with the dryers in the finish. This allows the finish to remain partially cured for an indefinite period of time. When the moisture content of the flooring increases and closes the spacing between the boards , the finish that has not fully cured squeezes out from the side joints of the maple strips and appearing like little BB’s on the surface of the flooring. When stepped on, poly balls flatten out or break open and leaving unsightly residue on the finish.

 

The floor should be swept daily to remove any poly balls that have broken free. A complete resurfacing is not necessary to remedy this minor problem. Contact your MFMA Installer or Finish Manufacturer for an evaluation for recommended remedial procedures. Extent and severity of poly balls varies dramatically, so a general recommendation is not possible.

 

The Maple Flooring Manufacturers Association (MFMA) recommends maintaining indoor relative humidities between 35 percent and 50 percent, and air temperatures between 55 degrees and 75 degrees year-round.

 

By limiting wide swings in atmospheric conditions inside the facility, you will reduce the expansion and contraction of the flooring system. If flooring materials are properly acclimated, a 15 percent fluctuation in indoor relative humidity will not adversely affect the maple. Excessive shrinkage and/or expansion may occur with indoor relative humidity variations in excess of 15 percent.

It is especially important to maintain this recommendation during the application of oil based floor finishing products. When conditions fall outside the recommended limits, finish oozing is a likely possibility, even if the floor was refinished several months before.

 

In buildings where air conditioning is not available, many facility managers make use of circulating or venting fans. Other facilities have vent windows or corridor doors available to open as needed to improve air circulation. Facilities without adequate HVAC equipment to regulate the indoor atmosphere, or those facilities which are "closed up" with no ventilation for long periods of time (summer breaks) are more likely to develop flooring problems directly related to environment.

 

POWER SCRUBBERS

MFMA does not recommend the use of automated power scrubbing equipment for general, daily, or weekly maintenance of your maple floor.

 

The use of power scrubbing equipment may void warranties administered by your MFMA maple flooring system manufacturer and/or sport floor contractor. Before incorporating general maintenance procedures for your gym floor, the Maple Flooring Manufacturers Association strongly recommends reviewing your warranty and maintenance information provided to you by your MFMA sport floor contractor and/or MFMA maple manufacturer.

 

The use of automated power scrubbing equipment for general, daily, or weekly maintenance procedures may lead to specific side effects listed below.

 

Possible effects to maple floor boards

  • Shaling

  • Splintering

  • Excessive shrinkage and expansion

  • Splitting of individual pieces of wood flooring

  • Raised or Uneven sides

  • Cupping

 

Possible effects to the floor finish and paint

  • Premature/excessive finish wear

  • Chipping and peeling of paint and finish

  • Swirl marks in the finish

  • Dull finish appearance

RADIENT HEAT

Without impairing the efficiency of the heating plant, strip maple flooring may be installed over concrete slabs in which radiant heating pipes are embedded. Such installations may require the maintenance of slightly higher water temperatures. Boiler temperatures should be controlled to limit the temperature of the slab surface to about 85 degrees, an acceptable level for most mastics. Also, to anticipate rapid changes in temperature, an outside thermostat should be installed.

 

As in any installation, it is important to employ proper concrete slab construction methods. There are varying specifications, but precautions must be taken to prevent the absorption of ground moisture through the concrete during the non-heating season. It is well to provide a gravel fill beneath the slab, preferably of washed gravel and a vapor barrier of at least 6 mil. polyethylene membrane between the slab and the fill. The maple strip flooring is installed as in any other project, except that if specifications require subfloor plywood, the plywood is not fastened to concrete with either nails or powder-actuated fasteners.

 

The heating system should be activated at least 4-5 days prior to delivery of the flooring in order to drive excessive moisture out of the slab. Perform a moisture test on the slab before proceeding with installation of the maple. Allow flooring to become acclimated to normal site conditions and then install according to manufacturer’s instructions. Regular sanding and finishing methods are then employed to complete the installation.

 

(Note: It is very important to check flooring and mastic manufacturers’ specifications for suitability of use over radiant heating systems.)

 
 
 

REFINISHING

Maple flooring is a hygroscopic material that expands and contracts due to the influences of moisture, temperature and humidity changes. The multiple application of sealers, finishes and paints on the surface of an installed maple floor can only slow down the rate of vapor transfer between the maple flooring and its environment. Such applications cannot stop the dimensional changes inherent in this natural product.

 

When a new maple floor is installed, sanded, sealed, painted and finished during the summer months, the maple's moisture content is usually at its highest annual level in most regions of the United States. In most locations, the onset of winter months results in lower relative humidities and ambient air temperatures. Such environmental changes can cause individual flooring strips to contract. The same can be said for existing maple floors that have undergone a complete resurfacing during the summer months. The removal of the existing floor finish, which typically consists of multiple coats, increases the vapor transmission rate and can cause the originally installed maple flooring to expand or contract at a faster rate than it did during prior years when multiple finish layers reduced vapor transmission rates and resulting flooring movement.

 

Such changes in the appearance of a newly refinished maple flooring system are not uncommon, and are a direct result of the recently exposed surface maple adjusting to a new environmental set point. As with newly installed floors, these resurfaced floors typically reach an equilibrium set point within their installed environments after 6-12 months. Future expansion and contraction cycles tend to be less pronounced.

 

ROLLER SKATING & ROLLER BLADING

MFMA does not recommend the use of roller skates/blades on a standard gymnasium floor. Nylon, plastic, and metal wheels can cause scuff marks and scratches in the gymnasium finish. Ongoing skating activities can shorten the life of the finish and skating accidents have the potential to cause damage to the maple flooring itself.

 

As you may know, MFMA maple is the preferred surface for use in roller rinks. However the finish application for a roller rink differs from that of a gymnasium, and the maple is always laid in the direction of the skating (usually in a hexagonal or octagonal pattern.) These minor differences in installation procedures produce a surface much more geared to skating use than installation procedures typically employed for recreational facility and gymnasium installations.

SCISSOR LIFTS

MFMA maple floor systems function extremely well under normal loads, however on occasion significant loads can have detrimental affects. Excessive loading like those resulting from the use of high point load scissor lifts can lead to surface degradation and/or weaken structural components leading to system failure.

 

MFMA always recommends using multi-layer protection when loading a flooring system with any size lift in order to protect the integrity of the system and quality of the surface finish.

 

Example, MFMA recommends that when a lift (total weight, machine, operator, and load not to exceed 4,500 lbs) is used on the floor system the floor should be protected with at least two layers of ¾” thick clean protective sheathing, with overlapping seams. Protective material should include suitable clean sheathing and floor finish protections such as red rosin paper.

 

When operating equipment, wheels should not travel outside of the protected area, this includes while the machine is stationary or being moved.

 

For lifts of any type where machine weight alone exceeds 3,500 lbs. consult Foster Specialty Floors (FSF) for further recommendations.

 

Note: Do not leave heavy loads on the floor overnight or for extended periods.

 
 
 

SHIMMING AND FLOATING FLOORS

Consistent with longstanding installation practices, MFMA does not recommend shimming of a floating floor system in order to compensate for concrete deficiencies. Slabs shall be leveled by normal means of grinding high areas and filling low areas to within MFMA recommended tolerances. Check with your system manufacturer for approved fill materials.

 

MFMA has published guidelines for flatness for concrete subfloors. These requirements are included in our guide specifications to significantly reduce any finished flooring performance difficulties resulting from irregular subfloor surfaces. Deviations from the MFMA’s guide of 1/8” in a 10’ radius subfloor specification can cause significant performance variations across a finished maple floor.

 

The general contractor shall provide a concrete slab, troweled smooth and level to a tolerance of 1/8” in a 10” radius, subject to the approval of the flooring contractor. F- Numbers are not applicable for gymnasium slab applications. Labor and materials necessary to put the concrete slab in acceptable condition (high areas ground down and low areas filled with appropriate leveling compounds) shall be the responsibility of the architect, general contractor, construction manager, owner, or concrete subcontractor.

 

SHRINKAGE CRACKS

Wood is a hygroscopic material. When exposed to varying temperatures and humidities, it will release or absorb moisture until it is at equilibrium with the surrounding atmosphere.

 

MFMA recommends that the facility's environment be stable when the flooring materials arrive -- air temperature between 55 and 75 degrees and indoor relative humidity between 35 and 50 percent. In some cases, the maple should be stored in the room where it will be installed for a period of time to acclimate. Consult FSF for specific acclimation information.

 

After installation, maple flooring typically requires a year or two to stabilize -- through a complete cycle of seasonal changes. The floor will continue to adjust to environmental changes throughout its life span.

 

The appearance of shrinkage cracks during winter months is not unusual. These cracks will normally close in the spring and early summer, as the floor picks up moisture from the air. We do recommend the use of humidification/dehumidification systems if available to maintain proper humidity levels.

 

If cracks persist, and the indoor atmosphere has been maintained between 55 and 75 degrees and between 35-50 percent indoor relative humidity (or no more than a 15 percent fluctuation between highest and lowest average IRH), contact FSF immediately.

 

SITE EVALUATION

It is good practice to schedule a site evaluation with the general contractor and architect/owner prior to commencement of any maple flooring installation. The site evaluation should take place no sooner than 30 days after the concrete slab is poured. At this time you can inform the involved parties of your on-site needs and requirements. Below are the things you should make the general contractor and architect/owner aware of during a site evaluation meeting:
 

  • All roof work should be completed, including flashing, guttering and exterior drainage.

  • The building must be permanently enclosed and weather-tight.

  • All block, brick, masonry, tile, marble and/or terrazzo work must be complete, cured and dried.

  • Concrete flatness and moisture content must meet the requirements detailed in MFMA Position Statements "Concrete Slab Moisture Content" and "Concrete Slab Flatness."

  • All interior painting must be completed and dry.

  • The permanent light, heating, electrical and ventilation systems must be operating.

  • All overhead work must be complete, and the floor area must be free of obstructions.

  • All backstops and sports accessory fixtures must be installed.

 

SOLID PAINTED AREAS ON MAPLE GYM FLOORS

Maple flooring is a hygroscopic material that expands and contracts due to the influences of moisture, temperature and humidity changes. The application of sealers, finishes and paints on the surface of an installed maple floor can only slow down the rate of vapor transfer between the maple flooring and its environment — such applications cannot stop the dimensional changes inherent in this natural product.

 

When maple flooring is installed, sanded, sealed, painted and finished during the summer months, the maple's moisture content is usually at its highest annual level in most regions of the United States. With the onset of winter comes dryer air and lower ambient air temperatures. Such environmental changes typically cause individual flooring strips to contract. With such movement, flooring strips that are painted a solid color (basketball keys, sidelines, and logoed areas) tend to exhibit more noticeable shrinkage due to the visual contrast between the solid colors and the cracks that develop between individual flooring strips. In some cases, the surface finish has been known to peel at the edges of individual painted flooring strips if the amount of shrinkage exceeds the elasticity of the paint or the finish. This is a direct result of the wood adjusting to a new environmental set point.

 

STAIN A MAPLE FLOOR?

Due to the extremely tight cellular structure and variable grain patterns inherent in northern hard maple, MFMA does not recommend staining or bleaching maple strip flooring under any circumstances.

 

While small areas of individual flooring strips may accept stain without difficulty, it has been our experience that much of the maple surface will appear uneven and "blotchy" following the application of most stains or bleaching agents.

 

MFMA strongly suggests contacting your floor finish manufacturer directly for specific tinting product recommendations and application instructions.

STAPLING & NAILING SCHEDULE

When attaching maple flooring directly to sleepers in a "floating" subfloor configuration, all MFMA specifications require installation of staples or nails at every intersection between surface maple and subfloor sleepers. Sleepers are typically spaced either 9" or 12" O.C. depending on the thickness of the surface maple. Occasionally due to performance requirements, specifications may require greater sleeper spacing in excess of 12" o.c. -- contact your MFMA system manufacturer for instructions and technical advice in all such cases.

 

When fastening maple flooring into a "panel" subfloor (plywood or OSB), MFMA manufacturer specifications require installation of staples or nails approximately every 12" O.C. Fasteners are also typically installed near the end of each piece of flooring -- usually around two inches from both ends of the strip.

 

When attaching multiple layers of subfloor plywood or other panel materials to each other, MFMA specifications require installation of subfloor component fasteners every 12" O.C.

 
 

STICKER STAIN

"Sticker stain" is the common term for shadowing or discoloration that occurs randomly on milled maple flooring as a result of lumber stacking that does not allow regular and even evaporation of maple sap prior to milling. "Sticker stain" marks, in a very moderate form, are occasionally present in new maple installations when maple strip is installed that was milled from maple lumber that has been air dried or stored outdoors at the mill particularly during the early spring months when sap content is high.

MFMA has no specification or regulations concerning the appearance or frequency of "sticker stain" in MFMA maple flooring installations. The presence of markings referred to as "sticker stain" does not denote a maple degrade. In other words, "sticker stain" is not considered a grading defect. This long-standing policy is recognized throughout the industry as an accepted standard. A complete list of grading factor admissions and restrictions appears on the MFMA Web site. Color variations from all sources (when occurring outside of areas of dark heartwood) are not considered grading defects in MFMA maple.

 

Typically, if "sticker stain" is present on a maple strip, the marks are nearly imperceptible during installation -- until floor sealer is applied. The marks tend to become less noticeable once game lines and remaining coats of finish are applied, particularly if the finish used is oil-based. Finishes with this chemical composition will amber over time, and minor imperfections on the surface of the maple strips (including "sticker stain") will blend into the surrounding flooring. The speed and degree of ambering varies from product to product, but most color change takes place between six months to fifteen months following the initial application. Note that water-based finishes do not amber over time.

 

If you are concerned about the presence of "sticker stain" marks on your maple surface, contact your flooring installer.

 

SUSTAINABLE FORESTRY AND FSC CERTIFICATION

The MFMA was established in 1897 as the authoritative source for the milling of hard maple, birch and beech flooring. The association members are highly aware of how important sustainable yield forestry practices are to protect this valuable resource.

America’s forests are renewable: six trees are planted for every one harvested in the US; harvesting large, mature trees lets sunlight reach the forest floor to stimulate growth; hardwood trees regenerate naturally; forest products companies and private timberland owners plant almost 4.8 million trees a day, 1.7 billion trees a year.

America’s forests are abundant: the US still has more than 70 percent of the forestland it had in 1600 – 745 million acres; despite a 165% increase in population, the US has about the same amount of forestland as it did in 1920; today’s forest growth exceeds harvest by 47%; 36.7% of total forest lands are reserved from harvest by law for commercial timber production; each year hardwood volume increases by 5.27 billion cubic feet.

America’s forests are sustainable: sustainable forestry involves managing for multiple benefits including clean air, clean water, recreation, wildlife, habitat and timber; professional loggers adhere to Best Management Practices to minimize the environmental impact of harvesting operations; for the last 50 years North America’s forests have been managed sustainably; foresters are trained to determine when and how trees should be harvested, ensuring healthy and productive forests.

The Forest Stewardship Council (FSC) is a non-profit organization that encourages the responsible management of the world’s forests. FSC sets high standards that ensure forestry is practiced in an environmentally responsible, socially beneficial, and economically viable way.

Landowners and companies that sell timber or forest products seek certification as a way to verify to consumers that they have practiced forestry consistent with FSC standards. Independent, certification organizations are accredited by FSC to carry out assessments of forest management to determine if standards have been met. These certifiers also verify that companies claiming to sell FSC certified products have tracked their supply back to FSC certified sources. This chain of custody certification assures that consumers can trust the FSC label. All MFMA Mill Manufacturers can provide FSC certified flooring.

SWIRL MARKS

Swirl marks, in a very moderate form, are fairly common in new maple installations where disc sanders are used in the flooring surface sanding process.

 

MFMA has no written policy or specification regarding the appearance or frequency of swirl marks in MFMA flooring installations. Generally speaking, minor swirl marks are apparent in some locations on most flooring installations. They are considered excessive if close-up inspection yields noticeable uneven or gouged areas of the flooring.

 

There can be a number of causes of swirl marks. The most common occurrence in the maple itself results from the use of disc sanders. These are very different from swirl marks between layers of finish, which are typically seen when lighting is reduced and angled reflections are observed.

 

Between-coat buffing is desirable to ensure proper adhesion of successive coats of finish, and in fact is required under certain finish manufacturer warranties. Flooring appearance in these cases is akin to a fresh wax job on a black automobile -- when viewed at a specific angle under specific lighting conditions, the marks are visible.

 

Swirl marks of this type are not damaging to the surface, nor will the marks impair the playability or performance of the system. Typically, the marks will soon begin to disappear as the oil-modified finish on the floor ambers with age.

 

The pace of ambering varies from product to product, but most color changes will take place between six months to fifteen months following the initial application. However, water-based finishes do not amber over time and if you think swirl marks are present, check the severity and contact your flooring installer

 
 

TAPE ON A MAPLE FLOOR

MFMA does not recommend the use of masking, theatrical, construction, electrical, duct, adhesive or any other kind of tape to mark temporary court boundaries on the surface of a finished maple floor. It is likely that the tape, when removed, will peel away layers of the floor’s surface finish. Most tapes promoted for temporary markings have a different coefficient of friction than finishes applied to the maple playing surface, and can impact a person’s ability to start, stop and pivot. Removing the surface paint/finish and exposing the maple can result in additional chipping and peeling of the remaining paint/finish in adjacent areas.

 

In addition, most commonly available tapes contain adhesive resins that can etch or stain the floor finish or even the maple flooring below the temporary markings.

USE OF 33/32 MATERIAL

The Maple Flooring Manufacturers Association (MFMA) is dedicated to the sustainable use of America’s forest lands, while providing the forest products critical to the nation’s well-being.  Since 1897, MFMA has been recognized as the authoritative source of technical and general information on maple flooring.  MFMA and its members are committed to providing the highest quality maple flooring manufactured from America’s forests.  We need your help to continue to do so for years to come.

More than one million Americans are directly employed in the forest products industry. Many millions more, employed in the home construction, home furnishing, transportation and heavy equipment industries, owe their jobs to this one basic industry that converts harvested timber to finished products.  The stewardship of raw materials is the responsibility of every one of us in the industry, including you. 

For many years, maple flooring has been specified and manufactured in several standard widths and thicknesses.  Certain sizes are specified based on subfloor configurations, adjacent flooring profiles, anticipated end-uses and performance characteristics.  With recent advances in flooring system technology, many specification choices have been simplified.  “Over-engineering” of wood flooring systems is quickly becoming a thing of the past.

One example of “over-engineering” is the use of 33/32” thick maple flooring in athletic facility applications.  Years ago, architects and specifiers required this product to be used on many installations to ensure structural stability and (assuming regular periodic resurfacing) to add years to the floor’s life span.  Over the past twenty years, MFMA manufacturers have invested heavily in the research of structural stability and performance issues for athletic flooring applications.  As a result, most of the integrated flooring systems produced today do not rely in large part on the surface maple for structural stability and system performance.  Subfloor design is the key.

There are numerous factors which impact the lifespan of a maple flooring system.  Our research has shown that a properly maintained standard 25/32” thick MFMA maple floor will provide four to six additional sandings after installation.  Following MFMA’s recommended maintenance schedule, this projects to a life span of at least 30-40 years or more.  Our research also shows that a properly maintained 33/32” thick MFMA maple floor will provide eight to ten normal sandings and has a life span of 60 years or more.  It is not uncommon for a 33/32” floor to last more than 100 years.


In 1997,  MFMA statistics showed that less than one percent of replacement floors were necessitated by depleted wear surface on the existing floor.  Floors are far more commonly replaced due to flooding, improper facility maintenance and even building demolition/replacement than are replaced due to the “wearing out” of the surface.  Simply stated, the specification and use of 33/32” thick maple flooring is in many cases a waste of a natural resource.

We’re asking for your cooperation in limiting the specifying of 33/32” thick MFMA maple flooring to projects for which it is truly necessary.  By reducing the number of installations for which this type of “over-engineering” is currently being done, we can reduce the waste of a natural resource and to allow the supply of maple hardwood to exist in perpetuity.

There are 730 million acres of forests in the U.S. -- one-third of the country’s land.
Each day, the forest industry, together with federal and state forest agencies, plants over 6 million more trees.  Together we are making significant progress in perpetuating this resource.  The next time you are considering premium flooring choices for a project, please take a moment to think about these issues, and specify your MFMA maple systems with care. 

 
 
 
 

WHY MFMA?

Since 1897 the Maple Flooring Manufacturers Association (MFMA) has been recognized as the authoritative source of technical and general information on maple flooring. MFMA has attracted a membership of manufacturing mills, installation contractors, distributors and allied product manufacturers who subscribe to the highest standard of quality for which the association stands.

The quality of this exquisite hardwood begins in the northern forests above the 35 th parallel where shorter growing seasons and longer winters produce a densely grained maple with rich, consistent color and fewer imperfections. MFMA maple comes with peace of mind and quality assurance. An MFMA mill number is embossed into the back of every strip of MFMA maple. It is our guarantee that strictly enforced MFMA grading rules and quality standards have been painstakingly followed in the production of each strip of flooring. It assures that the wood has been kiln dried to between 6% to 9% moisture content making each strip more dimensionally stable. It assures that the finished maple strip has been milled to consistently exact tolerances as mandated by the MFMA. Each MFMA mill is subject to periodic, unannounced third party inspections to assure strict adherence to MFMA rules governing continuity of specie, millage and grading of MFMA maple flooring. The Milling Company Manufacturer members of the MFMA have dedicated their production of solid strip maple flooring to the highest levels of quality.

 

Year after year, installation after installation, MFMA grading rules have assured consistent quality. Due to their prominent position in the athletic flooring market, the MFMA mills collectively continue to lead by establishing performance standards for sports floors. In the unlikely event that an on-site inspection of an MFMA floor is required, inspection and evaluation by qualified MFMA staff is available.

 
 

WOOD FILLER

As a rule, the MFMA does not recommend the use of fill material along the side joints of maple floors, due to the physical properties of maple strip flooring and commonly available maple fillers.

 

Wood fillers do not generally expand and contract with the surrounding wood. When wood flooring expands, fill can impede the natural movement of adjacent strips and cause permanent damage to the edges of those strips. When wood flooring contracts, fill can dislodge and cause aesthetic and safety concerns. Minor filling of pinhole knots and end-checks is generally acceptable, as fill in those areas is much less likely to dislodge due to the direction of movement in a gymnasium flooring system.

 

WOOD TREATMENTS

Wood preservatives and fungicides applied to wood products is a common practice for wood products exposed to the elements. It is essential for keeping exterior wood from rotting. However, wood products used indoors, like maple floors and subfloors components, do not need these treatments as they are not intended to be exposed to harsh conditions.

The MFMA no longer recommends Woodlife Products for use on maple floors or wood preservatives or fire retardants on subfloors associated with maple floors.

 

MFMA does not recommend pressure treating maple flooring or any wood subfloor components with water responded compounds (fire retardant compounds, wolman salts) for two reasons. First, the application of such compounds in maple flooring or wood subfloor components forces the treating compounds and excess moisture into the cells of the material causing them to swell beyond recommended limits. Second, the application of such compounds in maple flooring or wood subfloor components increases the susceptibility to wide moisture content variations due to the inherit nature of the compounds.

Using wood preservative and fungicides on interior wood products can hurt the environment due to gases released during the application, drying and eventual disposal of maple flooring and subfloor wood products.