Laying solid and engineered wood flooring using the glue-down method – Tutorial

This is the most common method used when laying wooden floors. It is quick, easy to carry out, and equally suitable for both solid wood floors, of all thicknesses, and engineered wood floors. It achieves good levels of sound insulation, often increased by the addition of specially designed insulating materials and can be used with all types of subfloor: screed, concrete, tiles, even over existing wood flooring. In humid rooms and over underfloor heating, wood flooring must only be installed using the glue-down method with a full surface bond. When laying wood flooring in dry rooms, glue can be applied in lines.

Prerequisites

Your floor installation will be unsuccessful unless certain essential prerequisites are satisfied: storage conditions, site humidity, subfloor humidity, flatness and expansion space.

For more information: Laying wood flooring: understanding the essential prerequisites for a successful installation.

Preparing the subfloor

Before proceeding with the installation, ensure you have the following items available:

- polyurethane or MS polymer glue

- line reel with blue chalk

- wooden spacers, 8 mm

- a serrated spatula

- a saw

The subfloor must be completely clean. It is essential to remove all dust and dirt.

Trace two perpendicular lines across the room in order to begin laying from the center.

Place a meter rule along one of the lines and paste glue over a 1m2 area (use a line reel with blue chalk).

Laying the floor

There are two ways of applying the glue: as a full surface bond or in lines.

Full Glue-down installation

Using a serrated spatula, carefully paste the glue onto the subfloor in crisscrossing strokes. Paste no more than one square meter at a time to avoid the glue drying before the floor is laid. This technique is suitable for dry rooms, for humid rooms, and for laying flooring over underfloor heating and/or cooling systems.

Glue-down installation applying glue in lines

The lines of glue must be at least 6 mm thick, must run perpendicular to the flooring strips, and must be placed at intervals of 10 to 15 cm. This method allows you to work with a minimum of space available for floor thickness, whilst at the same time permitting flatness variations of several millimeters to be compensated for. When applying glue in lines, sound absorption can be improved through the addition of a suitable resilient underlay. This method is not recommended for humid rooms or for installation over underfloor heating and/or cooling systems.

1. Install the underlay. When laying a wood floor over an underfloor heating and/or cooling system, or in a humid room, the insulating layer must be glued down using a full surface bond.

2. Begin laying the flooring from the room’s central axis.

3. Place the strips in position BEFORE gluing.

4. Position a rule to mark the placement of the flooring strips as you glue them into place, repositioning it as you progress.

5. Use a glue suitable for the wood flooring type. You should apply the glue at a maximum rate of 1 kg to 1.3 kg/m2 for a full surface bond, and one tube/m2 when gluing in lines.

6. Using a length of wood, press each strip down firmly to ensure complete adhesion to the underfloor.

7. Use a cloth to remove any excess glue from the edges.

8. Work on one small area at a time, checking squareness and alignment as you progress, and aim to finish the whole room in one day.

9. Leave an expansion gap of the recommended size at the edges, along the bottom edges of walls and other obstacles.

Note: If you are gluing down an insulating layer separately (double glue-down), use 1000 g/m², then use a maximum of 1000 g/m² again for the flooring.

Finishing off the installation

Hide the expansion gaps at the peripheries by installing skirting or beading matching your flooring.

Fill in the places where the flooring has been cut to fit around door frames and pipes.

Adjacent rooms

When laying different varieties of flooring in adjacent rooms, use room thresholds as boundaries, or use junctions between different floor sections where present.

When using the same variety of flooring in adjacent rooms, a decorative effect can be achieved by laying a flooring strip in the opposing direction to the rest of the floor at the threshold between the rooms. It is entirely possible to lay the same flooring across several rooms as a single area, leaving thresholds unmarked, on condition that the flooring is fully parallel to the walls in each room. Where this is not the case, it is better to mark room thresholds to avoid creating an undesirable effect.

Finishing the floor:

Factory finished, ready to lay flooring: no specific treatment required unless otherwise indicated by the manufacturer. As a rule, flooring protected with natural oil requires one final and additional protective coat after laying.

Untreated wood flooring: oiled, varnished, stained. There is a wide range of finishes available designed to protect and enhance the appearance of this type of floor.  Before applying the protective finish, it is essential to very carefully sand the floor. This will need to be done at least twice, if not three times in some cases.

Important: it is advisable to apply any final finishes to the floor BEFORE fitting skirting or beading along the edges (wait until completely dry, about 48 h).

Time taken for the flooring to settle after laying: 8 days minimum.

This installation advice is based on French building code DTU 51.2. It is provided for information purposes only and does not entail the liability of Decoplus in any way. The advice given here will, nonetheless, enable you to efficiently carry out the installation of your new flooring yourself. However, if problems are encountered, it is advisable to engage the services of a professional rather than risk irreversibly modifying your newly purchased flooring.