Nail Down Method

Note: THE FOLLOWING IS A GUIDELINE ONLY. CAREFULLY READ THE MANUFACTURER’S INSTALLATION INSTRUCTIONS THAT COME WITH YOUR PRODUCT BEFORE BEGINNING THE INSTALLATION.

Installer/Owner Responsibility

Hardwood flooring is a stunning natural product with inherent variations in appearance. It is the owner’s and installer’s responsibility for all products installed.

Before the actual installation, the installer and/or owner have to assume responsibility for inspecting the flooring as to grade, manufacture, color and finish. Another responsibility applies during his/her absence from the installation site. Keep in mind that if a flooring board is not acceptable, you should not install it. The next step is contacting the seller. Once a board has been nailed or glued down, it is deemed accepted by the installer and/or owner. Usually, manufacturers deny any responsibility for judgment errors and/or for poor installation quality of their products.

Tools and Accessories Needed:

• Power Miter saw
• Tenon-saw, circular saw or handsaw
• Claw hammer and nail punch
• Straight Edge
• Measuring Tape
• Moisture meter (wood, concrete or both)
• Chalk line and chalk
• Level and leveling compound
• #20 grit sandpaper
• Rubber Mallet and Tapping Block
• Pry Bar
• Filler stick and touch-up marker
• Utility knife
• Broom and dust pan
• Vacuum cleaner
• Ear plugs, safety glasses and dust mask
• Power nailer or stapler
• Electric drill and bits
• Hardwood flooring nails (nails or cleats)
• Finishing nails
• Flooring screws

• 15 lb Asphalt Paper

Temperature, Humidity, Storage and Handling

We all know that hardwood is a living material that naturally reacts to changes of relative humidity. According to each season, hardwood absorbs or releases humidity. The heating/air-condition system must be operational for least 14 days prior to installation and thereafter at a temperature of 65°F – 75°F to reach desired humidity level. The relative humidity level at home should be controlled between 35% – 55% at all times prior, during and subsequent to installation.

When humidity is high, hardwood absorbs the humidity in the air and expands, this causing the strips/planks of wood to push against each other. The floor is cupped or “cupping”. Proper ventilation could minimize these variations.

In winter, the relative humidity level is lower due to the usage of heating system. The lower humidity level results the wood releases its humidity and the strips/planks contract or shrink. We recommend to use a humidifier to minimize extreme shrinkage effects.

Keep in mind that hardwood flooring has to be stored in a controlled environment. Furthermore, materials should be delivered 72 hours prior to installation for the hardwood flooring to acclimate. Acclimation within a closed carton may not be adequate due to lack of air movement. You have to store the flooring in a dry place and provide air space under cartons. Remember to never unload or transport flooring during wet conditions. We already explained how the wood absorbs moisture, which causes it to swell.

Job Site Requirements

The building must be completely closed in with all outside doors and windows in place while the wall and painting should be covered before starting the installation.

Furthermore, you need to make sure basements and under-floor crawl space are dry and well ventilated. In addition to that, plastering and concrete work must be completely dry with minimum of 90 days curing time.

Exterior grading should be complete with surface drainage offering a minimum drop of 3″ in 10′ to direct flow of water away from the structure and all gutters and downspouts should be in place.

Remember the overall rule which let’s us know that solid hardwood flooring can only be installed on or above ground level with a plywood subfloor while engineered flooring can be installed above grade, at grade and below grade level.

Never install hardwood flooring in bathrooms. Check with the manufacturer’s instructions to determine if your hardwood floor can be installed over an in-floor radiant heat system.

Another thing you should have in mind is that crawl spaces must have a minimum of 24″ from the ground to underside of joists. A ground cover of 6-8 mil polyethylene sheeting is essential as a vapor barrier with joints lapped six inches and taped. The crawl space should have perimeter venting equal to a minimum of 1.5% of the crawl space square footage. These vents must be properly located to foster cross ventilation. In some cases, local regulations must be met. Another important thing is that crawl spaces must be dry and well ventilated. Check the plywood (subfloor) moisture content by using a moisture meter. Delay the installation if the moisture content of the plywood (sub-floor) exceeds 12%.

Engineered flooring can be installed over a dry concrete subfloor. If you want to test the moisture level of the concrete subfloor, tape 18″ x 18″ clear plastic sheeting to the floor in two spots, sealing all sides with moisture resistant tape. Leave in place for 48 hours and then remove. If there is no condensation on the underside of the plastic sheeting, the concrete slab can be considered dry enough to install the engineered flooring. If there is moisture on the plastic sheeting, there is a problem and the flooring cannot be installed. A professionally installed moisture barrier would be required. Using the moisture meter, check the moisture content of the hardwood flooring to ensure that it is within the acceptable moisture range of 6% to 9%. The installer and/or owner has full responsibility for moisture testing the wood or concrete subfloor and the hardwood flooring prior to installation.

Job Site Requirements

• Preferred ¾” CDX grade plywood with minimum of 5/8″ CDX grade plywood over joists subfloor
• Existing wood boards over joists subfloor and
• Dry Concrete subfloor (only for Engineered Floors and some thin profile solid wood floors)

Note: particle board or other similar type products are not suitable sub-floors.

Sub-flooring has to be clean, smooth and free of wax, paint, oil, sealers, adhesives, curing agents and other debris. Another rule is that sub-flooring has to be straight, flat and leveled. Sand high areas or joints. Flatten low spots with layers of builders felt, plywood or shims. Furthermore, sub-flooring must be structurally sound. Nail or screw any loose areas that squeak. Keep in mind to replace any damaged, swollen or delaminated sub-flooring.

Another rule is that the sub-flooring must be completely dry and respect the moisture content requirements. Sub-floor preparation is one of the most important steps before the installation of your new floor. Remember that the hardwood floor is only as good as what is underneath it. Laminated rosin paper or construction paper acts as a moisture retarder. This could be used to reduce the movement caused by changes in subfloor moisture. It could also reduce sound transfer and prevent noise.

General Instructions Before the Installation

• It is recommended that the flooring should be installed at a 90 degree angle to the joists for wood subfloors.
• An additional 5% flooring must be added to the actual square footage. This is needed for cutting and grading allowance.
• The flooring should be installed from several cartons at the same time. This ensures good color and shade mixture.
• Remove any existing base molding, other moldings, door sills and old floor covering where applicable. By using a hand saw, undercut the bottom of door frames 3/4″ to slide hardwood board beneath.
• It is the installer’s/owner’s responsibility to ensure that the conditions of the flooring are acceptable prior to installation. So do not use flooring pieces with obvious defects. Manufacturers generally decline any responsibility for flooring which is installed with obvious defects.

Nail or Staple Down Installation Guidelines

• Before continuing ensure that all the conditions from above have been respected. Now you have to mark the locations of joists on perimeter walls so that the starting runs and finishing runs, which require face nailing, can be nailed into joists. Staple down 15 lb. asphalt paper over the sub-floor, lapped 2″-4″ at seams. This prevents moisture from below also helps preventing squeaks in dry seasons.

  Note : some squeaking and crackling of the floor is normal when using the nail or staple down method. This is not considered a defect.

• Direction of the flooring should be installed at a 90 degree (right) angle to the floor joists. Expansion gaps of 3/4″ are required between flooring and all walls.
• Determine a starting wall and try to begin the layout from the straightest wall (which generally is an outside wall). Measure out from this wall at each end the width of one board (including the tongue) and then add an additional 3/4″ for expansion. At these measured locations, mark a chalk line parallel to the starting wall.
• Face Nail 1st Row: Keep in mind to install the first board along the chalk line while making sure that the tongue side of the board is facing away from the starting wall. Drill holes through the face of the board at 6″ intervals, with the drill holes located approximately 1″ from the back edge. Now you have to secure the starter board to the subfloor with 1″ long finishing nails. This method is done by driving the nails until the heads are just above the board, then sink the nails with a nail set.
• Blind Nail: The next step is drilling the pilot holes along the tongue side of the board by using an appropriately sized drill bit for the nails. Now you have to set the bit in the corner formed by the tongue and edge of the board, angled at 45 degrees. Drill pilot holes approximately every 6″ through the board, and up to 2″ from each end. Do not drill within 2″ from each end.
• Install the remaining boards of the first row following all the instructions outlined in Steps 4 (Face Nail) and 5 (Blind Nail).
• Subsequent Rows: You now have to be sure that the first board of the each subsequent row is at least 6″ longer or shorter than that of the prior row to maintain a staggered appearance. Next, securely fit the groove of the new board into the tongue of the previous row. Use a rubber mallet if necessary and tap block to achieve a snug fit. Now, as described in Step 5 blind nail the boards. The first few rows should be nailed by hand rather than with a power nailer or stapler because of the vertical wall obstruction. Subsequent rows may be installed using a power nailer or staples. This process eliminates the need for pilot holes. Respect the manufacturer’s instructions when using the power nailer or stapler and continue to nail/staple the tongue side of each board at a 45 degree angle and at 8″ intervals, but do not nail/staple within 2″ from the end of each board. Ensure that a long board is selected as the last board of the row, so that the cut portion of the last board can be used as the starting board of the next row. This method minimizes waste.
• Last rows: Because of to the end wall proximity, installation of the last 4 to 5 rows should be done manually. You just need to follow the instructions outlined in Step 5. The end row may have to be rip-sawed to leave the required 3/4″ expansion gap along the end wall. The end row must be faced nailed in place, by drilling holes through the face of the board at 6″ intervals, with the drill holes located approximately 1″ from the back edge (i.e. 1″ from tongue side). Secure the end board with 1″ long finishing nails, by driving the nails until the heads are just above the board, then sink the nails with a nail set.

Complete the Installation

• On of the final steps of the installation is vacuuming and cleaning the floor with proper wood flooring cleaner on a soft, cloth mop.
• Now wipe the area clean in order to remove loose dirt or soil.
• Reinstall all base and/or quarter round moldings. Nail the moldings into the wall, not the floor.
• Don’t forget to install any transition pieces that may be required (such as reducers, T-moldings and stair nosing).
• In the end remember to keep a few spare boards in the event of future repairs.