What is Red Ash?

Red ash is a type of burnt colliery shale that was often used in the United Kingdom. It is a byproduct of the coal mining industry and is typically red or brown in colour. Red ash was commonly used as a filler material in concrete floors during the post-war period, as it was a cheap and readily available material.

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However, red ash, along with other industrial type materials, contain sulphate, which can react with moisture and cause the concrete to expand and crack.

 

This is known as sulphate attack. The signs of sulphate attack include:

• Bulging or uneven concrete floors

• Cracks in the concrete

• White residue on the surface of the concrete

• Efflorescence (a white powdery substance) on the surface of the concrete

 

If you suspect that your property has red ash, it is important to have it tested by a qualified professional, which we can recommend if needed. Sulphate attack can cause significant damage to concrete floors, and it can be a costly repair.

 

Here are some additional information about red ash:

• It is typically found in areas where coal mining was once active, such as the North East of England, South Wales, and the Midlands.

• It is an industrial material that was used as an oversight prior to laying the concrete floors.

• It can cause sulphate attack in concrete, which can lead to cracking and doming.

• 'Red ash, sulphate affected floors, would need to be replaced and fully inspected by a Building Contracted governing body who will then issue a satisfactory certificate on completion.

 

If you are concerned about red ash in your property, it is important to speak to a qualified professional like Charles Developments. We would be able to assess the situation and recommend the best course of action.