More and more people ask us if they can lay an oak floor over a concrete sub-floor. As far as concrete is concerned, there are several issues that you will need to pay attention to:
1. We must consider for how long the concrete has been there. It is extremely important that concrete should have a moisture content of below 4%, no matter what wood flooring you will choose. If you do not adequately dry out the concrete sub-floor before laying the floor, the concrete will keep drying out as the flooring has been laid. The moisture level will go up, which will bring about problems with your new oak floor.
The concrete sub-floor which has been sufficiently dried will help you avoid that.
2. Decide how you are going to fit your oak flooring. The choice of the fitting method can influence the type of oak flooring that will be most appropriate for your household.
The method that is most popular when laying floors over a concrete sub-floor is gluing. This procedure consists in using an adhesive for firm adhesion of the floor to the concrete. If you’ve chosen this method, you can go for solid oak flooring, but it’s generally not advisable to glue boards whose width exceeds 120 mm.
The type of flooring that, in our opinion, would be most suitable for this method is engineered oak flooring. In this case boards guarantee higher stability, making the floor much more appropriate for gluing. You also need to remember that a proper adhesive must be used to guarantee adequate installation. For this purpose, we would recommend MS Polymer Wood Flooring Adhesive. This product guarantees full adhesion and, at the same time, has sufficient flexibility to allow for natural contraction and expansion of the wood.
A different fitting method that can be used for fitting a floor over a concrete sub-floor is floating. This method consists in gluing tongue and grooves of each board together, without directly fixing them to the sub-floor. This floor installation method is recommended only in the case of engineered oak flooring. Remember that a solid oak floor is not suitable for floating.
In the case of a concrete sub-floor, there is also an option of laying sufficient battens and fitting the oak flooring over the top. Then, you can fit the boards with the use of the screwing/nailing method.