New construction or remodeling
BUILDER AND INSTALLER CHECKLIST
The National Wood Flooring Association states, in their technical publication, A-100 Water and Wood, page 14, and Wego states that laying the floor should be the LAST STEP in your project.
Even BEFORE the wood flooring is delivered, make sure that:
A) The house is closed or sealed in with all doors and windows installed.
B) Plaster, paint, and plywood sub floors and/or concrete substrates are thoroughly dry.
C) All plumbing or wet trades must be completely finished.
D) The foundation is dry and the basement is well ventilated.
E) The floor in the crawl space (if it has one) is completely covered, overlapped, and lapped up the wall six inches by a 6-8 mil black polyurethane plastic film.
F) The heating or ventilation system is working properly and that the conditions inside your room(s) where the wood flooring installation is to take place have been kept at an approximate temperature of 68º F (20º C), and a relative humidity of between 40% and 50% for at least one week prior to the acclimation of the wood flooring to its normal climatic environment that it is to perform in.
G) Solid wood flooring is acclimated for minimum of at least one week prior to its installation (the wood manufacturer's installation guidelines do supersede). Furthermore, the room's temperature and relative humidity must be kept at the recomm ended levels shown above, with a constant flow of air across the floor, during and after the installation until the end user moves into the rooms and/or house and controls the climatic conditions to their preference.
A failure to make sure that EVERY ONE of these industry proven steps are meticulously followed can result in splits, cracks, cupping, buckling, board delamination, finish flaking, blisters, bubbles, face checks, and peeling, or other major problems with the wood flooring.
DO NOT INSTALL TOO EARLY
Wego International Floors and the National Wood Flooring Association agree that "pre-finished" wood floors are defined as a factory-finished product requiring installation only. When wood floors are installed, all other trades should have finished their work on the job site. By being installed the week before the closing date, the newly installed wood floors will be subject to less potential for damage. The floor will remain in top condition for the consumer's final walk-through.
Pre-finished wood floors should be climatized, as it is installed during the same time frame as carpet. By coordinating the timing of the two installations, there should be less construction traffic, and the heating and air conditioning units can be activated a week before the installation. If this industry proven practice is not followed, the installation will look great at move in, but shortly thereafter the floor will begin to separate. What caused the problem? Acclimation to the job site conditions. Where was the flooring stored on the job site for acclimation? The likely answer to the problem is that the pre-finished floor was installed too early. The product should not have been installed on the job site before the new home was under climate control for at least one week. The floor was stabilized to an elevated moisture content, not to conditions after move- in. Also, after move-in, the heat or air conditioning (air movement) systems removed a portion of the job site moisture from the wood, allowing a reduction in the face width which resulted in visual conditions such as: separation between boards (cracks or gaps), face checks, splits, cupping, delamination, raised grain, finish problems, etc.
DO NOT USE PROTECTIVE COVER
The use of protective coverings that are not "breathable" such as plastic, paper, cardboard, Masonite, carpet or carpet padding, etc., over new wood floors may cause future moisture related problems. Like a lid on a Tupperware jar, these kind of protective coverings will trap moisture normally being released by the boards and drive it back down into the wood flooring and subsurface. The overall effect is that of a "hot house" as the boards overheat and go into stress shock. This can result in elevated moisture levels, cupping, crowning, buckling, board delamination, peeling, or flaking of the finish, side and end joint gaps, stress fracture face checks, or split ends. This is NOT the result of any manufacturing deficiencies in the wood flooring product. The burden to resolve this issue is that of the person who chose to cover the floor.
PREVENTING GAPS BETWEEN BOARDS
If the wood flooring was delivered to a new home and was installed prior to the conditioning of the home through its air conditioning and heating system, gaps between planks may occur at a later date. In addition, there would have been no consistent movement of air across the new wood floor. When it was turned on, it would have caused the home to start drying out due to the dehumidifying action of the air conditioning and/or heat. During this time it extracts most of the moisture out of the wood floor, making the wood contract or shrink and allow objectionable gaps to occur. Wood flooring is a part of the interior finish. Just like a grand piano, wood flooring should not be delivered or installed until after all of the construction dampness is gone, the building closed in, and under complete, stable temperature and humidity control.
A) Letting a humidifier run in the home until the relative humidity comes within the recommended 40% to 50% level (preferably 45% - 50%) with the temperature between 60º and 80º F, preferably between 68º to 72º F. This level should be maintained for another two weeks until stable. Then closely examine these gapped planks.
B) As needed, rework the planks or replace the gapped planks. Once the floor has gone through a complete year of seasons and gaps have not filled up, they will remain gapped. Sanding and refinishing the floor will do nothing to improve the appearance. Filling in the cracks with putty would be a "band-aid" approach, as the putty will become loose and fall out as the boards expand and contract.
PRE-INSTALLATION WARNING: Wego International Floors is designed and manufactured to strict manufacturing tolerances for use in typical residential environments. Once our quality product "leaves our hands", we no longer have any control. Only you, the installation contractor, can conduct the mandatory moisture testing of the sub floor and boards to make sure they are within 2% or less of each other. If the interior relative humidity is too high or too low, you are responsible to alert all parties of the issues you're having. If the relative humidity is less than 40%, installed boards may cup, split, check, crack, shrink (or delaminate, if engineered). In such dry conditions, we recommend the use of humidifier to introduce moisture to the home. Floor boards installed onto a wet sub floor may experience checks, splits, crowning, cupping, buckling, shrinking, swelling, coreboard telegraphing (if engineered), delamination or edge or corning edge raise. It's possible the installed boards can be soaked from above by clean-up crews or other contractors in the home.
Again, conduct the MANDATORY moisture testing on the sub floor and new floor boards.
DO NOT INSTALL THIS FLOORING ON A WET SUB FLOOR OR WHEN THE HOME'S ENVIRONMENT IS EXPERIENCING DRY CONDITIONS.
RELATIVE HUMIDITY REALLY MATTERS
When the indoor relative humidity is maintained at a consistent level throughout the year, natural expansion and contraction of the boards will be minimized.
- During the heating season, forced air heating, wood stoves and electric heat tend to create very dry conditions. A whole house humidifier is recommended if the home has a forced air heating system. Otherwise, the use of a portable humidifier is a good choice. An average size portable humidifier is suggested for every 400 square feet of installed flooring. Be sure to read the humidifier's operating instructions for best results.
- Non-Heating Season: The reverse is usually the issue. The home's air conditioner or a dehumidifier should be used to lower the interior relative humidity if it exceeds 50%. Turning on the heating system periodically can also control the interior environment.
WOOD FLOORING HAS A COMFORT LEVEL, TOO
- Wood flooring will perform best when the interior environment is controlled to stay within a relative humidity range of 30% to 50%, and a temperature range of 60°F to 80°F. Fortunately, that's the same comfort range most humans enjoy. The chart below indicates the moisture content the wood will likely have at any given combination of temperature and humidity. Note that equilibrium moisture contents in the recommended temperature/humidity range coincide with the 6% to 9% range within which most hardwood flooring is manufactured. Although some movement can be expected even between 6% and 9%, wood can expand and shrink dramatically outside that range.
- Wood floors perform best when the interior environment’s relative humidity range is kept between 35-50% (preferably 45-50%). The temperature range from 60-80 degrees Fahrenheit is acceptable, but the ideal temperature is 68 degrees Fahrenheit.
- Relative humidity is 45%.
- Temperature is 68 degrees Fahrenheit.
When these guidelines are not maintained, damage to your wood floor will be most likely to occur. Some of these objectionable appearances can be, but are not limited to, dry cupping, cracking, splits, cracks, gaps at joints, delamination of plys, finish is issues such as peeling, flaking, chipping, rupturing, wet cupping, tenting, buckling or noises emitting from the floor when walked on.
It is extremely important to keep the environment surrounding your wood floor at the "normal" living conditions as described above. If necessary, heating systems, air exchanges, air conditioners, dehumidifiers, whole house or portable humidifiers should be used to control these environmental conditions.
Because wood is a natural material that is hygroscopic, it constantly reacts to the moisture (relative humidity), high or lack of in the home’s environment.
While the temperature of the interior environment is an important factor, it is absolutely critical to maintain a relative humidity of no lower than 35 percent and no higher than 50 percent.
Stagnant air is not good for wood flooring; therefore, we recommend that you leave the HVAC system’s fan switch in the "On" position to provide a flow of air across the floor.
If away from home, the climate controls should be left within the parameters suggested above.
The key to preventing future problems with your hardwood flooring is to keep the job site environment within its comfort zone at "normal living conditions". See the peach colored box in the chart below.
|MOISTURE CONTENT OF WOOD AT VARIOUS TEMPERATURE AND RELATIVE HUMIDITY REDINGS|
Table Key:The far left column represents interior temperature of the job site. The lower column represents the relative humidity level of the job site. The corresponding value represents the likely moisture content of the hardwood flooring, given the job site temperature and relative humidity values.
The values highlighted this color represent the ideal moisture content levels of the hardwood flooring (and the corresponding ideal job site temperature and relative humidity levels).
|Chart taken from Wood Handbook: Wood as an engineering material, (Agricultural Handbook 72), Forest Products Laboratory, U.S. Department of Agriculture.|
Moisture meter manufacturers state that moisture meters accurately measure the moisture content of wood products when the moisture content is in the range of 6% to 30%. Any moisture meter readings outside of the range of 6% to 30% will not be scientifically accurate. Through deductive reasoning and the data obtained from the Forest Products Laboratory, US Department of Agriculture, an accurate estimation of the wood's moisture reading can be determined.