A sulphate attack on a ground floor slab is a very serious problem which can cause structural problems to a building in the future.
This occurs when the material beneath the slab contains sulphates which migrate into the concrete and react with it. This causes the concrete to expand, resulting in heaving of the slab which can lead to potential structural damage to the external walls. Consequently, eventually the concrete will weaken and disintegrate.
When this happens, any internal walls built upon the slabs will be lifted and may cause damage to the structure above.
A sulphate report with Allcott Associates also includes observations on any movement, cracking or distortion to the external walls around the damp-proof course level, the internal ground floor walls and the slab itself. We examine the condition of the concrete and any presence of dampness is also recorded.
These factors could either indicate a sulphate problem or could increase the risk of a future sulphate attack.