Maintaining a consistent, normal heat and relative humidity
(average living conditions) before, during and after installation will ensure minimal shrinkage, expansion and stress of the hardwood floor.
Only deliver the wood flooring to site after the site has been confirmed dry and the temperature is at approximately 20c.
Concrete subfloors: Residual moisture in the concrete substrate exceeding a 3 lb MVER (Moisture Vapor Emission Rate) has the potential to cause swelling, buckling and shrinkage of the flooring product. Use the wood flooring manufacturers recommended moisture test or the NFCA approved Anhydrous Calcium Chloride test method and perform this test in accordance with ASTM F -1869.
Plywood subfloors: For plywood substrates confirm that the plywood is dry all the way through its thickness at 12%. There should be no more than a 4% spread in moisture content between the subfloor and the hardwood flooring. Think about what is below. If there is excess moisture present it will migrate through the plywood reaching the hardwood in a matter of days causing expansion problems.
There are no guarantees against gaps between the hardwood pieces, so avoid choosing light woods such as natural maple because any gaps will show up black and in strong contrast to the lighter wood surface.
Note that most flooring issues are caused by improper site conditions, excess moisture levels in the subfloor, acclimation of the hardwood flooring to wrong site conditions and inadequate subfloor preparation.
The following ‘Acceptable Conditions’ must be confirmed prior to shipping wood flooring to site.
• The home must be at lock up stage and the interior protected from outside conditions – all outside windows and doors must be installed.
• All wet trades such as tile and dry wall mudding should be finished.
• Wall paint: If water based paint is to be used, apply undercoats prior to flooring delivery. Final coat and touch ups can be applied after installation.
• If a cementitious underlayment is used to level the subfloor it should NOT be poured while the flooring is on site. Once poured, confirm the cement underlayment is dry before delivering wood flooring to site.
Special note: The subfloor must be flattened to NFCA standards which are:
Straight Edge Method: 1/8” + or – over 10’ in 360 degrees.
• The heating systems thermostat dial must be installed and operating so that gradual (5 degrees per day) temperature adjustments can be made as necessary.
• The indoor ambient temperature should be set at approximately 18 - 20c.
• Floor temperature should not be allowed to exceed 26c or dip below 15c.
• Ambient relative humidity should be maintained between 35% and 55%
• With these conditions established, the flooring should be delivered and left in the installation area for a minimum of 4 days with any plastic wrapping around the packs cut open. For solid wood flooring an acclimation period of 7 days is recommended. Always check individual manufacturers instructions and do as they instruct.
• Flooring should be stacked in a log cabin fashion on the heated floor to facilitate air circulation.