Solid flooring installation

These conditions should be achieved prior to delivery of the flooring, maintained during installation and in perpetuity thereafter. NOTE: Temporary propane heaters - torpedo heaters - produce large amounts of moisture and should be avoided.

Test and document photograph temperature and relative humidity in each room receiving Somerset flooring. A temperature range of f and r. Always test for moisture regardless of conditions to identify any hidden issues that may arise. Prior to delivery of the wood flooring, test and record the jobsite conditions and the subfloor moisture to ensure they are suitable for wood flooring delivery.

Elevated readings must be resolved prior to delivery of any wood flooring. Again check and record photograph the MC of the wood subfloor. Check a minimum of 20 locations for the first 1, square feet, and an additional 4 readings per square feet thereafter, and average the results.

Write test results directly on the subfloor at each location, including date, and photograph this notation. Test locations should be representative of the entire project and include a minimum of three tests per room receiving wood, with special attention to exterior walls and plumbing.

In general, more readings will result in a more-accurate average. Take readings of a minimum of 40 boards for the first 1, square feet, and an additional 4 readings per square feet thereafter, and average the results. More readings will result in a more-accurate average. Any flooring with unusually high or low moisture readings should be isolated and not installed in the floor. The average of the wood subfloor readings should coincide with the manufacturer requirements.

Any unusually high or low readings must be addressed prior to wood flooring installation. If moisture testing indicates flooring and subflooring are not sufficiently acclimated, more acclimation is required.

Also, note solid wood does not change moisture content and thus dimension uniformly. This may adversely affect the installation. Concrete subfloors must be moisture tested, and adequate moisture control systems in place prior to installation of any solid wood floor. When the wood flooring is delivered at a MC that coincides with the expected in-use conditions, and coincides with the subfloor moisture conditions as tested, and these conditions will be maintained indefinitely, the flooring may be installed immediately.

Record, date, photograph, and document all results — protect your business. Moisture Testing Methods [NWFA page ]: Understanding how to evaluate jobsite moisture and avoid or resolve any moisture related problems is critical to the success of every hardwood flooring installation. Test methods and equipment vary widely. Selection of both varies depending on the type of flooring and subflooring involved in a given job.

Regardless, the installer must understand the equipment and test methods required to properly evaluate moisture on every hardwood-flooring job. The single biggest variable — operator error. The installer is responsible to test and record photos moisture conditions on every job. Basements and Crawlspaces: Basement conditions will change from season to season and may affect the flooring above. Finished basements are normally maintained similarly with the above living space, but be sure the end user understands how any changes will affect flooring above the basement.

Treat any unfinished basement as unconditioned space. Crawl space ventilation is critical to avoiding crawl space related moisture issues. The minimum net area of ventilation openings is 1 square foot for each square feet of under-floor space area; unless the ground surface is covered by a Class I vapor retarder material.

Where a Class I vapor retarder material is used, the minimum net area of ventilation openings is 1 square foot for each 1, square feet of under-floor space area. One such ventilating opening shall be within 3 feet of each corner of the building.

These crawl spaces may result in a balanced condition below and above the flooring system. Substrates - Wood [NWFA ]: Wood Subfloors: Wood flooring is not intended to add structural strength or stiffness to a subfloor; the wood flooring installation is only as good as the subfloor beneath it.

Plywood subfloor panels should conform to the most-current U. Voluntary Product Standard PS 1 performance standard on the date it was manufactured. Oriented strand board OSB subfloor panels should conform to the governing version U.

Voluntary PS 2 on the date it was manufactured. Single layer subfloor panels should be installed continuous over two or more spans, with the long panel dimension strength axis perpendicular to floor trusses or joists.

All panel edges not supported continuously with framing shall be tongue and groove. To minimize the potential for floor squeaks, all subfloor panels should be glued and nailed or screwed to the floor framing using recommended fasteners and subfloor adhesives conforming to ASTM D or APA Specification AFG Both layers must be fully acclimated see acclimation section , and gapping and fastening requirements remain as for single layer subfloors.

This top layer may alternately be installed diagonal to the base layer. No base vs. Fastening schedule should be the same as for single layer subfloors.

All end joints require full bearing on a joist, fastened with a minimum 8d rosin-coated or ring shank nails or equivalent. Wood subfloors - conditions required: Subfloors must be structurally sound. Document any such conditions with notes in the job file including photographs. Subfloors must be flat. Level is typically not necessary, but reasonably flat is very important. There are various means of correcting subfloor flatness; for more information see NWFA Installation Guidelines, page Subfloors must be dry.

The builder is responsible to control moisture during the building process. The installer must confirm subfloor moisture conditions are suitable before installing any hardwood floor. Any damage due to moisture exposure swelling, distortion, etc. Subfloors must be clean. Remove any debris present, and address any contamination that may compromise the installation.

Lightweight concrete is not suitable for direct glue-down of Somerset solid hardwood flooring. Subfloor Toppings may be used to flatten or smooth concrete, but must be compatible with the adhesive chosen and meet psi, same as the base slab itself. Topping must also be completely dry before Somerset hardwood flooring installation.

Document slab conditions including photos and notes in the job file. The concrete surface over which Somerset hardwood flooring is being installed direct glue-down must be compatible with the adhesive chosen. That includes: Free of any contaminants that may compromise adhesive bond.

This includes old adhesive residue, curing compounds, waxes, oils, paint, dust, drywall compound, etc. Surface porosity is critical to the performance of any adhesive; follow adhesive manufacturer recommendations for appropriate CSP ratings.

Wood subflooring may be mechanically fastened, full spread glue-down, or floated. All concrete conditions as previously defined above must be met. Wood panels must be properly acclimated and meet the same standards as previously defined under Substrates — Wood. If using pressure treated panels, they must be kiln dried after treatment and fully acclimated to site conditions.

A Class-I impermeable vapor barrier is strongly recommended. Any new subflooring and the old flooring under it must be fully acclimated see acclimation section. New flooring may be installed nail or glue down directly over existing wood flooring if installed perpendicular or at least a degree angle to the existing floor. Any glue down installation requires checking compatibility of the adhesive with the existing flooring.

Existing Ceramic, Terrazzo, Slate, and Marble may be installed over using glue down methods only. Refer to the concrete subfloors section for more information. Many such substrates will require abrasion to create a good bond for the adhesive. Carpet: Never install hardwood flooring over carpet or carpet pad.

No vapor retarder is necessary under the new wood floor when installed over a conditioned space maintained at the same temperature and humidity as the living space directly above. No vapor retarder should be installed under the wood floor if a Class I or Class II vapor retarder exists on the underside of the joists. Do not deliver wood flooring to the jobsite or install wood flooring until appropriate temperature and humidity conditions have been achieved.

Appropriate temperature and humidity conditions are defined as those conditions to be experienced in the building after occupancy. Do not deliver wood flooring to the jobsite or install wood flooring until all concrete, masonry, plastering, drywall, texturing and painting primer coats are completed.

Basements and crawl spaces must be dry. If power washing is required in the basement, do so before wood flooring is installed and allow subfloor and basement to dry before installing wood flooring. Crawl space earth or thin concrete slab should be covered percent by a vapor retarder of black polyethylene minimum 6 mil or any recommended puncture-resistant membrane, such as Class C, meeting ASTM D See Figure Crawl Space Conditions a.

Where a proper ground covering is in place and when venting is required by local building codes, the crawl space should have perimeter venting equal to a minimum of 1. Note: Local-building codes may differ. Follow local building codes. For crawl spaces without ventilation openings, vapor retarder joints must overlap a minimum of 6 inches and be sealed or taped.

The vapor retarder should also extend at least 6 inches up the stem wall and be attached and sealed to the stem wall. Continuously operated mechanical exhaust and perimeter wall insulation or conditioned air supply and insulation must be provided. Note the grade level so that the correct type of flooring and system can be specified for the job.

Engineered and floating floors can be appropriate for above-grade, on-grade and below-grade installations. Solid wood flooring can be appropriate for above-grade and on- grade installations, but not for below- grade installations. If the soil surrounding a structure is 3 inches or more above the floor of any level, consider that level below grade.

This includes walk-out basements. In addition, the surrounding soil should be sloped away from the structure.