GF Engineered Wood installation guide

1. Where GF Engineered Wood can go

GF Engineered Wood is water-resistant, not waterproof. It suits living rooms, bedrooms, dining rooms, hallways and kitchens with sensible care. It is not suitable for bathrooms, wet rooms, basements, outdoor areas or poorly ventilated rooms.

2. Choosing a fitting method

Glue down	The main method for GF Engineered Wood, over concrete, screed or plywood, and the recommended method over underfloor heating. The adhesive supports the wood across its whole surface. Click-jointed boards should only be glued down over underfloor heating; otherwise float them.
Secret nailing	For tongue and groove designs over a timber subfloor. Nails or flooring screws go through the tongue so they are hidden. Not for concrete unless a timber layer is fixed over it first.
Floating	Only for GF Plank designs listed as “glue down or float” on the GF Plank spec sheet, laid over a suitable wood-flooring underlay. Herringbone and Versailles must not be floated.

3. Tools and materials

• Tape measure, pencil, combination square, spirit level and chalk line
• Saw (hand, chop or electric), chisel, drill
• Spacers, a tapping block, a pull bar and a rubber mallet
• Moisture-testing equipment suited to your subfloor
• For gluing: a flexible wood flooring adhesive and the trowel its manufacturer specifies
• For nailing: a flooring nailer, or flooring screws and a screwdriver bit
• For floating: a wood-flooring underlay, damp-proof membrane and tape
• Knee pads, safety glasses, ear defenders and a dust mask

4. Delivery and acclimatisation

• Check the design, quantity and batch, and that nothing is damaged. Do not fit boards with visible faults: set them aside. Up to 5% of boards in a pack may be unsuitable, and short or offcut boards can be used around the edges.
• Lay the packs flat, with even weight, in the room where the floor will be fitted for at least 72 hours, at 18–27°C.
• Wet trades such as plastering and screeding must be finished and fully dry, and the room should be at normal living conditions, before the wood is delivered.
• Oak varies naturally in colour, grain and knots. Open three or four packs at a time and mix boards as you go. Colour and grade variation is part of real wood and is not a fault.

5. Subfloor preparation

Condition	Clean, dry, sound and level. Remove the old floor covering, adhesive residue and debris.
Flatness	Within 3mm over 2m. Grind down high spots and fill hollows with a levelling compound.
Moisture	Test concrete and screed with a suitable meter. Fit a damp-proof membrane: a liquid DPM under glued floors, or a polythene DPM under a floating floor. Never fit over a damp subfloor.
Joists	Fix tongue and groove plywood or OSB over the joists: 19mm for joist spacings of 406–486mm, 19–22mm for 487–608mm and 22–28mm for 609mm and over. Check it is level again afterwards.

• Fit kitchen units and islands before the floor.
• Suspended timber floors must be well ventilated underneath.

6. Underfloor heating

• GF Engineered Wood can be used over underfloor heating, preferably glued down. The floor surface must never exceed 27°C.
• Raise the heating gradually during acclimatisation and after fitting, following your heating supplier’s guidance. Avoid sudden changes.

7. Expansion gaps

• Leave a 10–12mm gap at every wall, and around pipes, door frames, thresholds and fixed objects, whichever fitting method you use. Wood moves with the seasons.
• Cover the gaps with skirting, beading or thresholds fixed to the wall, not to the floor.

8. Fitting planks

1. Work out the width of the last row and trim the first row if needed so the last row is at least 60mm wide.
2. Start along the longest wall with spacers in place and make the first row perfectly straight. It sets the line for the whole floor.
3. Glue down: spread adhesive about a metre ahead of the row you are laying, following the adhesive manufacturer’s instructions. Lay the boards into it, closing the joints with a tapping block.
4. Secret nailing: lay the first row groove to the wall and surface-fix it. Then nail or screw through the tongue of each board at an angle. Surface-fix the last row too.
5. Floating (listed plank designs only): lay the underlay first, then click the boards together, or glue the tongue and groove joints if the design is tongue and groove.
6. Stagger end joints from row to row for a natural look, using the offcut from one row to start the next where it is long enough.
7. Fit the last row with a pull bar and mallet, keeping the expansion gap.

9. Fitting herringbone and Versailles

1. Glue down or nail these patterns. Do not float them.
2. Herringbone uses ‘A’ and ‘B’ boards that are mirror images of each other. Sort them into two piles before you start.
3. Snap a chalk centre line down the length of the room, with a line at 90° to it and parallel guide lines for the outer edges of each strip.
4. Dry lay the first strip and check the pattern before fixing anything. For herringbone, the point of each strip sits on the centre line. For Versailles, the centre of each panel sits on the line, and you fill in the centre square first and then work outwards.
5. Work in small areas, fixing each strip and checking it against your guide lines as you go.
6. Cut and fit the perimeter pieces last, keeping the expansion gap.

10. After fitting

• With glued floors, keep foot traffic and furniture off the floor for 24 hours while the adhesive sets.
• Unfinished designs must be sanded lightly and finished with a suitable wood floor oil or lacquer, following the product’s instructions, before the floor is used.
• Look after the floor as described in the GF Engineered Wood care guide.