Gluing an Engineered Floor

Step 1

Measure out in two places from the installation wall a distance equal to the width of several planks (include the tongue in the measurement) plus the expansion gap recommended by the manufacturer. Snap a chalkline. If you're concerned about not being able to see the entire chalkline beneath the glue, secure a straight board to the floor and align it between the guideline and the wall.

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Ensuring a glue-down success

Some special concerns to keep in mind when gluing down engineered wood planks include the importance of properly preparing the subfloor before applying adhesive. For example adhesive will not stick well to concrete floors that have been previously sealed or painted and have not been properly prepared. Or if you suspect that the moisture content of your concrete floor may be somewhat high, select a glue that's formulated to double as a vapor barrier.

It's crucial that the concrete floor is flat, with high spots ground down and low spots filled with an approved leveling compound. Poor preparation such as using glue not recommended by the manufacturer or not using enough adhesive can result in popping noises or loose planks in the future. Following the manufacturer's guidelines (for the flooring as well as for the adhesive) results in a long-lasting installation.

Check the instructions that come with your flooring to determine what type of trowel to use when applying adhesive to the subfloor. The spacing of the notches determines how much adhesive is laid down. One way to check if you are putting down the correct amount of adhesive is to immediately lift up a plank that you have just installed. If at least 80 percent of the back of the board is coated with adhesive, the plank should adhere nicely.

Read the adhesive manufacturer's directions and follow them closely. Some adhesives must cure for a brief time (called "flash time") before laying the planks. Others require that you lay the planks immediately after spreading the adhesive onto the subfloor.

During installation try to avoid sliding the backs of planks through the adhesive so that boards aren't inadvertently pulled out of position as the glue dries. Plan to wait 24 hours before walking on the surface or returning furniture to a glue-down engineered wood floor.

For best appearance install the flooring parallel to the longest, straightest wall (generally an outside wall). However the flooring should be laid perpendicular to floor joists to prevent sagging.

Step 2

Using a trowel and adhesive recommended by the manufacturer, spread adhesive on the floor. Apply only enough to an area that you can surface with flooring in about 15 to 20 minutes.

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Using a Trowel: Holding a trowel at 45 degrees

When applying adhesive hold the trowel at a 45-degree angle to the floor as shown. This will allow you to cover 40 to 60 square feet of subfloor per gallon.

Keep in mind that the notches will leave very little adhesive between the ridges, allowing chalklines to remain visible so you can lay boards straight.

Otherwise plan to install a temporary guide board as a dimensional marker indicating the location of the chalkline.

Step 3

Facing the tongue of the plank toward the guide board, slip the first plank into position. Snug the end of the next plank into the end of the first plank and lay it down into the adhesive, making sure the groove is against the guide board. Continue working your way down the row in this manner. Cut the last plank to length, leaving the recommended expansion gap.

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Clean adhesive from surface

Whether you are gluing planks to the subfloor or edge to edge, wipe the surface frequently to remove excess glue. Use a cleaner recommended by the flooring and adhesive manufacturers. To prevent a difficult-to-remove residue haze from forming on your new flooring, switch to a clean towel as needed. Never apply blue painter's tape to the plank surface before wiping away the adhesive residue as the tape may be difficult to remove later.

Step 4

For the second and subsequent rows, stagger end joints as suggested by the manufacturer. In some cases you may be able to use the leftover length from a preceding row as the first piece in the new row.

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Step 5

Snug boards end to end first, then slip the tongue into the groove of the preceding row. Once you cut the last board in the row to fit (allowing for the recommended expansion gap), snug it into place using a pry bar. Place a scrap of wood between the end of the bar and the wall to avoid damage.

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Step 6

Continue laying rows of engineered wood planks across the room, kneeling only on portions of the unsurfaced subfloor. (Or use a kneeler board to distribute your weight.) Stagger end seams as suggested by the manufacturer.

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Step 7

As you reach the last row on the opposite wall, if you must be on the flooring you just laid, distribute your weight on a kneeler board. Rip-cut the planks for the last row if needed, allowing for the recommended expansion gap.

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Step 8

After 24 hours (or using a kneeler board), return to the wall where you started the installation and remove the guide board. Rip-cut the planks for the last row as needed.

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Step 9

Use a piece of scrap wood to protect the wall as you use the pry bar to snug the last row into place.

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Rolling the floor

Never strike the flooring with a rubber mallet because it may damage the plank surface. Instead use a foam-covered roller (if recommended by the manufacturer) to bond the planks to the subfloor and ensure more uniform adhesion. Check with the adhesive manufacturer to see what weight roller to use -- 100 pounds is common. Wait the recommended amount of time before rolling the floor but don't wait too long. If the glue is too dry, the rolling process will be ineffective.