Go to content Go to search
Free tickets to Grand Designs Live London Excel, 4 to 12 May 2024 London Excel, 4 to 12 May 2024

How to prepare the subfloor for wood flooring?

To prepare your subfloor, you’ll need these tools: a moisture measurement tool, a vacuum cleaner, leveling compound, a trowel, a hammer, a chisel and a regular or automatic screwdriver.

The condition of your existing subfloor

The first thing to do before you install a wooden floor is to inspect the existing subfloor. Any bumps or irregularities on the subfloor will cause problems later on in the installation, so we recommend taking enough time for a thorough preparation.

Remove floor covering and skirtings

Remove any existing floor covering. For glued subfloors, the existing floor covering must be completely removed. For floating floors, remove any carpet, needle felt or other non-waterproof coverings first. If the existing floor covering is waterproof, such as PVC or linoleum, it doesn’t have to be removed. However, always use a suitable, high-quality underlay.

We recommend removing old skirting boards too. You can install new ones once the new wooden floor is in place. Use a hammer and chisel to do this.

Check for damage

Check your subfloor for damage and any loose parts. Don’t worry about minor damage. As long as big chunks aren’t missing from your subfloor, you can install your floor safely over the damaged part. Screw – don’t nail - down any loose parts. Nailing down loose areas increases the risk of the floor becoming loose again in the future.

If there is a crawlspace underneath the wooden subfloor, contact your dealer for more information.

A clean and dry subfloor is key

After this is done, make sure the subfloor is perfectly dry and clean. Remove all traces of grease, residue or glue. Check for stray nails and carefully vacuum the floor.

Check the moisture content of your subfloor with your moisture measurement tool. The moisture content needs to be less than CM < 2,5% (75% RH) for cement-bound screed and 70% RH CM < 0,5% (50% RH) for anhydrite-bound screed.

If the moisture content is higher or may become higher other types of damp proofing must be used. If floor heating is used, cement subfloor requires a CM < 1,5% (60% RH) and anhydrite subfloor requires a CM < 0,3% (40% RH). Make sure that the moisture content of a wooden subfloor is less than 10%. Not sure about the tools? Ask your local dealer for advice.

Is the subfloor level?

Pro-tip: Use one of your planks to check if the subfloor is level. The subfloor shouldn’t have any irregularities greater than 2mm per 1 meter, AND 1 mm per 20cm.

If your subfloor is uneven, take your trowel and some leveling compound to smooth out all irregularities. Remember that using the right underlay will also prevent problems with small height differences.

Learn more:

Watch the video

Was this article helpful?
How can we improve this article?

Thank you for your feedback!

Oops. Something went wrong.

An unknown error has occurred. Please try again. If the issue continues, please get in touch.