Damp Proofing

Should we lay flooring on an unsealed/damp solum?

Anonymous user 09/03/2024 - 2.58 PM

We've just bought a 300 year old terraced cottage which we're now renovating. When we lifted the existing laminate flooring on the ground floor, we found a subfloor comprising only of chipboard which was nailed onto joists. Beneath the joists there are a series of empty cavities of about two foot in depth separated by the original dwarf walls. The base of the cavities is exposed soil which is damp and unsealed and is carpeted in fungal growth. Patches of the existing chipboard were damp and rotting away. There is some, but limited ventilation coming into the subfloor from the neighbouring properties but no airbricks to the front or rear. We have been advised that laying moisture resistant chipboard on the joists and attaching some form of damp proof coating to the bottom edges of the joists will be enough to to prevent the moisture rising from the ground to the joists. Given the extent of the fungal growth on the soil, this doesn't feel like enough protection to prevent either moisture or dampness spreading. Should we treat the fungus and/or seal the solum before laying any flooring at all? Any advice would be much appreciated.