Either solid wood flooring or engineered wood flooring can be laid directly onto joists if the planks are at least 18mm thick. It is also advised that long length boards (6ft or 1.83m) are used. This is to provide the strength and stability needed when installing hardwood flooring directly onto joists.
Before laying the floor
Before installing a hardwood floor onto joists, it is essential that the joists are secure, level and dry. To ensure that the joists are secure, check that they are structurally sound. The level of the joists can be checked with a straight edge or spirit level. To ensure the joists are dry, a moisture meter should be used to test the moisture content. A reading of 16% MC (Moisture Content) or below should be given before any hardwood flooring is installed. If the moisture content is higher than 16%MC, the joists should be allowed to dry naturally, and then retested before laying the hardwood floor.
Ways of securing the floor down
Whether using solid wood flooring or engineered wood flooring, the planks must be laid perpendicular to the joists. There are two ways of fixing the floor to the joists: secret nailing and secret screwing.
Secret nailing
Each plank of hardwood flooring (either solid wood or engineered wood) can be secret nailed directly into the joists. A toothed nail, approximately 50mm long, should be used to secure the flooring plank to ensure it does not pull back out of the joist. Do not use a brad nailer or a finish nailer, as they have smooth nails which could easily draw out from the joist.
Secret screwing
Each plank of either solid wood flooring or engineered wood flooring can be secret screwed directly into the joists. Special screws called Tongue Tites should be used as they are designed especially for securing flooring down. [caption id="attachment_200" align="aligncenter" width="215"]
Under floor heating
Under floor heating can be used if engineered wood flooring is being laid. The under floor heating system should be installed in between the joists, and the engineered flooring planks should still be either secret nailed or secret screwed directly onto the joists.
