The subfloor is the existing floor in your property. There are various types of subfloors, including wooden floorboards, concrete, screed, plywood, chipboard, bitumen and asphalt. Before you start to install your hardwood floor, you must ensure that your subfloor has been properly prepared and is ready for the installation process to begin. If your subfloor is not of a good quality it can cause irreparable damage to your hardwood floor, such as warping, cracking, raising up and discolouration.
Here are some simple steps to follow
Ensure you subfloor is flat, level, dry, clean and ready for installation:
1. Ensure your existing subfloor is flat and level by using a straight edge or spirit level.
If it is not level then one of the following can be done:
• A wooden subfloor can be lined with plywood with a thickness of at least 8mm.
• A concrete/screed subfloor can be covered with a self levelling compound to smooth out the unevenness.
2. Ensure your existing subfloor is dry by checking the Moisture Content (MC) with a wooden floor moisture meter.
• A wooden subfloor should be 16%MC or below.
• A concrete subfloor should be below 6%MC. If your subfloor is not dry, allow it to dry naturally before being tested again. 
3. Ensure your existing subfloor is clean by sweeping and removing any chemicals or adhesives that may react with products you will be using during the installation process.
