It is important to establish the moisture level in the subfloor before fitting your new wood floor.
If the subfloor is timber, you should take moisture readings across the entire area, looking for a consistent average across the readings of no more than 2-3%. If you have an isolated high reading, that isn’t normally anything to be concerned about. However, if humidity and moisture fluctuate significantly across readings, you shouldn’t ignore this.
If your subfloor is concrete and recently laid, you’re likely to face more of a potential problem when it comes to moisture. Ideally you should aim for a reading of 35-40% air humidity and/or 2-3% moisture content in the concrete.
On average, a concrete slab takes a month per inch to dry out, and in many cases the ideal moisture and humidity percentages are very difficult to obtain.
In this instance a surface damp proof membrane can be applied to help address the issue. We recommend either Sika Primer MB, a two-component solvent free, low viscosity epoxy primer; or Sikabond Rapid DPM, a one-component, low viscosity epoxy primer which dries in approximately 45mins.
You should never lay a new floor over a subfloor that has issues that have not been resolved.