HomeBuyer’s Reports reveal red ash effects

A HomeBuyer’s Report is really worth having before you purchase a new house. Along with well known and potentially very expensive problems such as dry rot and damp, the reports can reveal less well known but potentially even more devastating issues. One of these is the presence of red ash.

What is red ash?

After the second world war there was a great shortage of building materials and in some regions, particularly mining areas, colliery shale, also known as ‘red ash’ and blast furnace slag were commonly used as filler materials underneath concrete floors. The problem with this is that red ash contains sulphate and using this as a building material can cause what is known as sulphate attack.

What is sulphate attack?

Sulphate attack occurs when moisture gets through a concrete floor to the red ash below. Sulphate in the red ash reacts to the moisture and penetrates the concrete, which expands and makes the floor ‘heave’ and ‘crown’. In extreme cases walls can be damaged as well as a result of structural issues.

Unfortunately, red ash was not identified as a problem until the 1970s and no records were kept of how many houses it was used in.

Buying a property with red ash which is causing significant damage can typically cost a home owner between £10,000 – £20,000 to rectify. This is not usually covered by insurance. If a waterproof membrane has been used in the construction, this can significantly reduce the effects.

Tell tale signs of red ash

Tell tale signs of red ash can be floor doming, unexplained cracks and splits and skirting lifting.

A visual inspection of the property in a Level Two RICS HomeBuyer’s report means that the surveyor has the opportunity to look out for signs consistent with red ash. Further to this, comprehensive in-office investigations are carried out to identify the likelihood its presence. A surveyor can then advise the client whether a further red ash test is advisable.

If you are looking to buy a property, talk to the Forge team about how our RICS certified surveyors can help you with a Level 2 HomeBuyer’s report.