Engineered wood, tongue and groove

Before you start

This guide covers engineered wood flooring with tongue and groove edges. It follows the installation guidelines of the National Wood Flooring Association (NWFA). If anything here differs from the instructions in your carton or your warranty, follow the carton and warranty.

What you need

• Tape measure, chalk line, and a straightedge at least 6 ft long
• Moisture meter for wood, and a moisture test for concrete if you have a slab
• Spacers for the expansion gap
• Saw, tapping block, pull bar, and a rubber mallet
• The adhesive, underlayment, or fasteners rated for your method

1. Prepare the job site

1. Finish all wet work first: paint, tile, plaster, and concrete. The building must be closed in, with windows and doors in.
2. Run heating and cooling so the home sits at normal living conditions, 60 to 80°F and 30 to 50 percent humidity, before the flooring arrives and throughout the job.
3. Bring the cartons in and let them acclimate for 3 to 5 days. Keep the cartons closed, flat, and off the slab and outside walls.
4. Read the moisture of the flooring and the subfloor with the same meter, and write the numbers down.

2. Check the subfloor

The subfloor must be clean, dry, flat, and solid.

• Clean: scrape off paint, glue, and plaster. Sweep and vacuum.
• Dry: test concrete before you install. Use a calcium chloride test (3 lb or less per 1,000 sq ft per 24 hours) or an in-situ humidity probe (75 percent or less). Over a crawl space, make sure the ground is covered with a vapor barrier and the space is vented and dry.
• Flat: no more than 3/16 in of gap under a 10 ft straightedge, or 1/8 in under a 6 ft straightedge. Sand high spots. Fill low spots with a patch made for the subfloor.
• Solid: screw down any loose or squeaking wood panels.

3. Choose your method

Pick the method that fits your subfloor.

• Glue down: full spread of the approved adhesive. Works over concrete and wood.
• Nail or staple down: over wood subfloors only. Fasten within 2 to 3 in of each board end and every 6 to 8 in along the board.
• Floating: boards are glued together at the tongue and groove and rest on an underlayment. They are not fastened to the subfloor.

4. Plan the layout

1. Measure the room and find the longest, straightest wall. Boards usually run the long way of the room, or across the floor joists on a wood subfloor.
2. Do a dry layout of the first rows. Measure so the last row is not a thin sliver. If it would be, trim the first row so both sides end up close in width.
3. Open several cartons and blend the boards as you go. This mixes color and grain.
4. Stagger the end joints. Keep the ends of boards in neighboring rows at least 6 in apart.

Leave an expansion gap

Wood moves with the seasons. Leave a gap of 1/2 to 3/4 in at every wall, and use 3/4 in in large rooms. Leave the same gap around pipes, door frames, and fixed cabinets. Spacers hold it while you work. The floor ends under the baseboard, which covers the gap.

5. Install the floor

1. Snap a straight chalk line for the first row. Put spacers against the wall.
2. Set the first row with the groove side facing the wall (or as the carton directs). Make sure it is straight. Every row after it follows this one.
3. Lock each board in by tapping the tongue into the groove with a tapping block. Never hit the board edge directly.
4. Follow your method: for glue down, spread adhesive with the trowel size printed on the adhesive label. For nail down, fasten within 2 to 3 in of each end and every 6 to 8 in along the board. For floating, run a continuous bead of wood glue in the groove of every board.
5. Wipe any adhesive off the surface right away with a clean cloth and the cleaner the adhesive maker recommends.
6. Check the lines every few rows. If a row drifts, correct it before it spreads.
7. For the last rows, use a pull bar and tap the boards snug. Trim to leave the expansion gap.

6. Finish the job

1. Pull out all spacers.
2. Install baseboards and shoe molding. Fasten them to the wall, never down through the floor.
3. Fit transitions at doorways and where the floor meets other floors. Allow the floor room to move.
4. Sweep up and check the surface for glue, dust, and debris.
5. Stay off a glued floor for the time the adhesive maker states. Wait before you move heavy furniture.

Care and maintenance

Recommended cleaner

We recommend Woodwise Hardwood Floor Cleaner. It is a no-wax cleaner for prefinished wood floors. Mix and use it as the label directs, spray lightly, and wipe. Try it on a hidden spot first.