How to lay hardwood flooring

Solid wood flooring must be attached to the sub floor meaning you have the choice to either glue it down or nail it in place. It is not possible to have a floating solid wood floor. This means that the process of installing a hardwood floor is more technical and takes a bit more time.

A glue down floor is the most expensive and labour intensive of all the options but it will provide the most durable results. However, a number of rules must be followed if you want your solid wood floor to last.

Steps

1. Prepare to install your hardwood floor

2. Repair and prepare your surface

3. Check humidity levels and acclimatise the wood

4. Dry fit your first row

5. Glue down the hardwood flooring

6. Optional: laying your solid wood flooring over underlay

It is possible to lay a hardwood floor over a range of different surfaces including concrete, old wood flooring, tiles, etc. However, your surface needs to be prepared in advance. Beware that 80% of problems arise from a poorly prepared surface so do not skip this step.

Similarly, be sure to follow each step carefully. Some steps are extremely important, even if they don't necessarily appear to be! Wood is a natural material that will move over its lifetime. If you fail to install it correctly, it will warp which won't make for an attractive finish.

For better acoustic or thermal insulation, you might want to install an underlay underneath the hardwood floor.

Underlays must be glued down to the sub floor before the solid wood floor is glued over the overlay.

Some underlays are perforated meaning the glue will seep through every layer at once preventing you from having to glue twice, which uses up a lot of time and a lot of glue. Simply fill all the gaps of the underlay with a special adhesive and that's it!

Please note: this guide deals with glue down hardwood floors. This is the most common method these days. However, it is possible to nail down timber floors and this method is often used to renovate old wood floors.

In short, your surface must be clean, flat, dry, in good condition and reasonably porous.

Proceed as follows:

• Clean your surface using a broom or vacuum cleaner. Dust may prevent the adhesive doing its job properly.

• The surface must be perfectly level: a tolerance of 5mm every 2 metres is acceptable. Beyond that, you will need to level the floor.

• All cracks or holes must filled or repaired before installation.

It is essential to test the moisture level of your surface before installation using the appropriate tools (for example, a carbide bomb test or humidity sensor). Water is the number one enemy of wood! Any moisture in the surface will cause problems for glue down wood floors as water will quickly infiltrate through the flooring and eventually cause it to misshape or 'warp'. The humidity level of any traditional surface must be under 3%. If you have underfloor heating, it must be under 2% and if you are laying over anhydrite screed, it must be limited to 0.5%. The surface must not be too porous. To check this, pour a drop of water on the surface; if the water takes 1 to 5 minutes to penetrate the surface, you can go ahead and install your wood floor. Once the surface has been prepared and you are satisfied with the humidity level, you can place all of your wood flooring in the room in which it will be installed. This should be done at least 48 hours before installation to give the wood time to acclimatise.

Start by deciding the direction in which you want your wood floor to be installed. This decision will largely be driven by aesthetics but there are also some practical considerations. If you want to avoid making too many cuts, think carefully! You might want to mark out on the floor where you want your first row of boards to go, but this isn't strictly necessary. However, it is essential to leave an expansion gap of at least 8mm around the room. PVC spacers will be the most effective way to maintain the perfect gap. It is highly recommended to do a dry run of your first row, meaning laying your boards out without gluing them down. The length of timber boards will usually vary. Be sure to open at least three different packets to compare lengths and mix the boards together. Do not group together all the short boards on one side and the long ones on another. This will not give you good results. Start by putting one board in place and slotting together a few more on the shortest side of the board until one row is complete. Finish by cutting the last board to the right size to enable you to slot it into place. A pull bar can be really useful to get the last board in a row into position. Once you've checked everything, you can move on to gluing down the boards.

Be careful: the glue you choose must be suitable for the type of hardwood floor you are laying. Some adhesives are limited to a certain board width. You must also use the right type of adhesive spreader since this tool determines how much adhesive you should apply.

The adhesive must only be applied to the surface, not the wood flooring itself. Work in small areas at a time meaning a maximum of one or two rows. Once you have applied adhesive to the surface, slot your second row into place taking care to space out the joints of the boards. The joints between each board in one row should be placed at least 25cm away from the joints in the next row for a more attractive finish. However, be sure to read the manufacturer's instructions since this may be different depending on the boards and room type (for example, if there is moisture present).

Follow the same process until the entire surface is covered. You might want to tap gently on a tapping block with a mallet to ensure the boards slot together more easily. Any kind of obstacle will require you to make cuts and some objects are trickier to cut around than others. Do not forget to leave an expansion gap of 8mm around any obstacles. It is essential that the hardwood floor is not in contact with anything.

Pay special attention to door frames. If the wood floor is left touching the door frame, it will misshape the whole floor within a couple of weeks of it being installed.

You can then move on to fitting skirting boards or scotia beading to cover up the expansion gap and leave a perfect finish. Glue your skirting boards into place using a special adhesive and make your cuts using a mitre saw.

Required skills

Laying a solid wood floor is a fairly technical process that should only be tackled by confident DIYers. You will need to know how to use a jigsaw or circular saw, take accurate measurements and be able to work on your knees and follow all installation instructions to the letter. Solid wood floors are expensive and the look and durability of the material depends largely on how well it is installed.

Time required

A full day for a room measuring 20 m² (not including varnishing or oiling the floor).

Number of people required

One person.

Tools and equipment

• Broom or vaccum cleaner

• Circular saw (best option) or jigsaw

• Tape measure

• A utility knife

• A mallet

• A tapping block

• Spacers

• Measuring square

• Flooring pull bar

• Adhesive and adhesive spreader