Installation - Engineered Floors

Modified on 2007/12/27 13:17 by Administrator — Categorized as: Somerset Hardwood

Installer / Owner Responsibility

Somerset products should be installed by a qualified hardwood flooring mechanic. Many important decisions affecting the performance and appearance of the installed floor must be made on the installation site, and therefore are the responsibility of the installer and/or owner. These include, but are not limited to, complete evaluation of site conditions including moisture testing of the entire site and flooring, acclimation of flooring to proper site conditions, site preparation, flooring layout, milling, grade and color, proper installation methods, and clean up. DO NOT INSTALL any flooring if there is any question as to acceptability — INSTALLATION CONSTITUTES ACCEPTANCE. Additional technical information can be obtained from the National Wood Flooring Association at

Site Conditions, Handling, and Storage

Somerset engineered hardwood flooring may be installed above, on, or below grade (outside soil level).

Somerset floors must be installed after all other construction that may affect them is completed. Concrete, drywall, plumbing and any other “wet work” should be thoroughly cured.

Keep flooring dry at all times. Provide good air circulation around pallets, bundles, or cartons. Do not stack flooring bundles or cartons more than three layers high, and maintain a flat stack. Record flooring moisture content upon delivery and at time of installation for future reference. Acclimate Somerset Flooring to proper site conditions; refer to NWFA guidelines for further information.

Factory finished flooring is finished wood work, and should be handled carefully to avoid damage to the finished face, edges, corners, etc.

Permanent HVAC must be in operation before, during, and after installation. A temperature of 70 degrees F +/- 10 degrees and a relative humidity between 35-55% is recommended. Heating units or un-insulated ductwork close to the flooring or sub-floor may cause “hot spots” which must be eliminated prior to installation.

Radiant Heat: Somerset engineered hardwood flooring may be installed over modern radiant heat systems (excluding exotic species). As installation and system conditions are very detailed, please consult NWFA and the manufacturer of the heating system for further details.

Site Moisture is the most important factor.

Confirm proper drainage exists around the structure. In crawl spaces, exposed earth must be fully covered with minimum 6-mil polyethylene sheeting. Crawl space vents must be open at all times, and must equal at least 1.5% of the total square footage of the crawl space. Basements must be dry and remain dry.

Sub-Floor Types And Conditions


The sub-floor must be clean, dry, flat (within 3/16” in 10’), and structurally sound. Correct any joints or areas that are not flat. Securely fasten any loose boards or panels. Wood:

CDX plywood or OSB subfloor/underlayment grade is recommended. The subfloor must be dry (within 4% of hardwood flooring moisture content) and not exceeding 12%. Minimum single layer sub-floor thickness is 5/8” plywood on 16” o.c. joists or 23/32” OSB on 19.2” o.c. joists. The flooring must run perpendicular to the floor joists, or additional sub-floor thickness is required (refer to NWFA for more details).

Concrete: Lightweight concrete is not an acceptable subfloor; use a floating panel subfloor over lightweight concrete (refer to NWFA for details).

Concrete must be tested for moisture. If a concrete moisture meter or phenolphthalein test indicate moisture presence, perform a calcium chloride test. Moisture content must not exceed 3 lbs./1000 sqft./ per 24 hours. Moisture barrier systems must be used correctly and must be compatible with the adhesive used. Check with the moisture barrier manufacturer for details.

Installation Preparation

Allow 1/2” expansion space between the wood flooring and any walls or other obstructions. Undercut door jambs, casings, drywall, etc. A clearance of 1/16” above the floor is recommended so the floor fits underneath and allows proper expansion space. Layout

The best appearance is usually achieved by installing parallel to the length of the room, but always install perpendicular to the floor joists unless special sub-floor conditions are met. Always rack out the flooring before installing to avoid clustered end joints and repeating patterns. Work simultaneously from several cartons to achieve good color distribution.

Installation with Mechanical Cleats/Staples:

Use caution to avoid edge and face damage during installation. Special footer plates are available for flooring tools to protect factory finished flooring faces and edges. Use backer boards of ½” plywood ripped to an appropriate width to establish straight lines. Backer boards should be secured to the sub floor and carefully aligned with starter lines. Use flooring fasteners (appropriate type for engineered flooring – check with gun mfgr.) minimum 1” long, but avoid conflict with concrete under subfloors and radiant heat systems. Air pressure should be regulated so the fastener does not interfere with full tongue/groove engagement, does not split the wood, or distort the face veneer. Fastening schedule should be every 4-6”, with a fastener within 2” of each end, and at least two fasteners per piece. Face nail only as required with 1” (4d) finish nails or cleats, ½” from the groove, pre-drilling the nail holes to prevent splitting. Face nails need to be counter sunk and covered by molding or properly filled. Direct Glue Installation:

Use a quality hardwood flooring adhesive. Follow all practices recommended by the adhesive manufacturer including but not limited to adhesive storage, room temperature and humidity, proper ventilation, spread rate, open time, rolling, safety procedures and equipment, clean up and cure time. Avoid allowing adhesive residue to dry on the face of the flooring. Special cleaners are available (from the adhesive mfgr.) to clean off any residue. Aggressive solvents may attack the finish, so test any cleaner for finish compatibility before using on installed flooring.

Floating installation:

Somerset engineered flooring may be floated over a structurally sound subfloor, using a quality floating floor adhesive (PVA type) applied in a continuous bead along the bottom of the grooves (both long edges and ends). A quality floating floor underlayment product should be installed between the sub floor and the flooring installation. Other installation instructions remain unchanged.

Finishing Touches

Somerset offers five standard molding profiles factory finished to blend with your Somerset wood floor. These moldings will address most trim and transition situations quickly and cost effectively, and should be ordered with the flooring to avoid needless delays in closing.Fill any nail holes or small cracks with the proper filler (Somerset Touch-Up Kits are available). Leave the Touch-Up kit with your customer for their use as needed.Clean the floor thoroughly and remove all scraps and debris. Leave care and maintenance information for the consumer. A Somerset floor care kit makes a good closing gift, and starts them on the right maintenance program.Note: Applying additional finish over the factory finish may cause problems and does not improve durability or seal the joints. Any finish materials used that are not recommended by Somerset Hardwood Flooring will void your warranty.If you have questions about proper installation, contact Somerset, your Somerset distributor, or the National Wood Flooring Association (