3 / JOBSITE INSPECTION & PREPARATION CONT’D SUBFLOOR PREPARATION AND RECOMMENDATIONS FOR ALL INSTALLATIONS • Subfloors must be clean and free of dirt, curing compounds, sealers, drywall mud, paint, wax, grease, urethane, or other materials that may affect the integrity of the flooring material or adhesives used to install the flooring. • All subfloors and subfloor systems must be structurally sound and must be installed following their manufacturer’s recommendations. Local building codes may only establish minimum requirements of the flooring system and may not provide adequate rigidity and support for proper installation and performance of a hardwood floor. Whenever possible install the planks perpendicular to the floor joists for maximum stability. • Our warranties DO NOT cover any problems caused by inadequate substructures or improper installation of said substructures. • The subfloor must be flat, meeting a minimum of 3/16” within 10’ or 1/8” in 6’. • Concrete subfloors - Grind high spots or use a Portland-cement based levelling material (minimum compressive strength 3000 psi) to fill all low spots. Follow the levelling compound manufacturer’s instruction. Levelling compounds must be allowed to thoroughly cure and dry prior to the installation of wood flooring. • Wood subfloors - Sand down high spots and fill the low spots with a levelling compound or other material approved for use under wood flooring. For glue and nail/staple down applications, staples must be able to penetrate for holding power. Make sure wood subfloor is screwed down solid and secure, and nothing loose. Ensure that there is proper expansion space (1/8”) between the wood subfloor panels. SUBFLOOR MOISTURE CHECK THE RECOMMENDED WOOD FLOORING ADHESIVE MAY BE USED FOR ABOVE, ON, AND BELOW LEVEL APPLICATIONS AND ON ALL COMMON SUBSTRATES. CONCRETE SUBFLOORS SHOULD BE TESTED FOR MOISTURE PRIOR TO INSTALLATION IN THREE LOCATIONS TESTS PER 1,000 SQUARE FEET OF SURFACE AREA AND ONE ADDITIONAL TEST FOR EACH 1000 SQUARE FEET THEREAFTER. FOR SLABS ON GRADE AND BELOW GRADE, INCLUDE A TEST LOCATION WITHIN THREE FEET OF EACH EXTERIOR WALL. WOOD SUBFLOORS SHOULD BE TESTED FOR MOISTURE AT SEVERAL LOCATIONS IN THE ROOM – A MINIMUM OF 20 PER 1,000 SQUARE FEET – AND AVERAGE THE RESULTS. DOCUMENT ALL RESULTS. A HIGH READING IN ONE AREA INDICATES A PROBLEM THAT MUST BE CORRECTED. PAY SPECIAL ATTENTION TO EXTERIOR AND PLUMBING WALLS. ACCEPTABLE CONDITIONS FOR ABOVE, ON, AND BELOW GRADE APPLICATIONS ARE: CONCRETE: • Less than 1.4kg (3lbs)/ 95m2 (1000’sqft) /24 hrs on a calcium chloride test. • No greater than a reading of 4.5% on a Tramex Concrete Moisture Encounter (moisture meter). • RH testing using In-Situ probes/sensors (ASTM F 2170-02): Results should not exceed 75% RH. WOOD: • Test wood sub floors and wood flooring for moisture content using a pin-type moisture meter. Take readings of the subfloor – minimum of 20 readings per 1000 sq. ft. and average the results. • Wood Substrates must have a moisture reading of less than 12% when using a suitable moisture meter and differential between boards and subfloor must be less than 4%. If it exceeds these limits, DO NOT install the flooring. New concrete slabs require a minimum of 60 days drying time before covering them with a wood floor. (They must be fully cured). To correct any subfloor problems concerning moisture, either wait until the subfloor dries to meet specifications or use an appropriate moisture barrier. NWP INSTALL GUIDE JOBSITE INSPECTION & PREPERATION 4
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