In damp or wet conditions, the underside of the concrete floor is vulnerable to sulphate attack, with needle-shaped ettringite crystals growing and causing high internal stresses. Moisture can carry the sulphates through the concrete slab, causing them to evaporate at the surface, leaving behind salts.

If the floor contains a significant concentration of water-soluble sulphates and some kind of barrier, such as non-carbonated concrete or concrete containing calcium silicate hydrates, evaporation cannot take place and damage will inevitably occur. This may be an unevenness in the floor, followed by cracking and in the worst cases, walls may be pushed out.

We can arrange a site visit and test the floor to ascertain the extent of the sulphate attack and the level of remedial treatment that is required.