5 Stages to Fix Red Ash Properties

In ‘The Potteries’ Red Ash is rife but what is it? Why is it a problem? And what can you do to resolve this hidden issue? In this guide we will show you how to identify, remove and sell your property with red ash.



Firstly, red ash is an issue which will be found under your floors. As a byproduct of the pottery manufacturing process, ash (red & black) was used as a cheap and plentiful alternative hardcore when building houses post war. That is why if your property is located within certain areas of Staffordshire and was built in the 1940’s up until the 70’s, it could contain traces of “ash” within it’s perimeters. Even if you do not plan to sell your property with red ash, it is important to resolve the matter before further structural damage is caused.

How can you tell?

Well it is possible that your floors have ash without any telltale signs, however, those less fortunate will display signs of the floor bulging and becoming uneven. This is due to moisture reacting with the sulphates present in the red ash and causing it to expand. Often a white residue is also visible between floor tiles. Fear not, there is a cure and ash will not be present in suspended timber floors or those above the ground floor. Be sure to instruct a floor survey to be carried out before going any further.


The removal of red ash is no easy task and it could result in your property becoming temporarily inhabitable. The process will require whatever flooring you have to be removed, then you will need to break the concrete sub floor, this will allow access to the contaminated ground below where the ash is contained. All of the contained ground will need removing, this can become a very physical task.

We would recommend to all readers that you explore the option of having a professional to carry out this process. How deep you dig is at the discretion of your building control, usually it will be to dig until you hit clay or a similar stable material, this can be from as little as 1 foot to as much as 4 feet deep. During this stage, labour and waste removal costs are high.


Now that the contaminated ground has been removed and your building control officer is satisfied (it is important for them to visit at every stage of the process) it is now time to infill the hole you have created.

For the approval of building control and to prevent any issues with mortgages in the future, your new floor should now be reinstated to modern standards. Check with building control officer what their requirements are, usually the new flooring will consist of, a hardcore base typically around six inches deep, then a sand “blinding” layer, this will prevent the hardcore puncturing the next layer which will be a damp proof membrane (DPM). DPM is a durable plastic sheet, similar to a tarpaulin, this will act as a damp proof course to prevent moisture creeping into your new floor. Next is the insulation (typically 100mm of rigid insulation board, the foil backed type), then ANOTHER layer of DPM, this keeps the insulation protected from the concrete layer. Finally around 6 inches of concrete will need to be poured level throughout and smoothed, this will be your final floor level.


Your new concrete floor needs to be left to cure. After 24 hours you will be able to walk on the floor. It is then advised that you wait a minimum of 28 days before tiling or installing any other form of flooring.

The finished texture of your floor will be due to the quality of craftsmanship when smoothing the concrete with a float, water content and aggregate size can also play a factor. You may find that before installing your finished flooring, a silicone based self levelling is required to smooth out the surface.


Now you have restored order to your home it is important to have it signed off by your building control officer. The certificate will need to be supplied to conveyancing solicitors should you come to sell, mortgage companies will also look more favourably on the property when it comes to lending.



Resolving the issue of Red Ash is a very expensive and invasive process. You can instruct a professional to carry out these works, a typical quote for a two/ three bedroom terraced property will be between £6,000 – £10,000.

You could also decide not to go through the hassle and expense by selling your property at an auction or to cash buyer like Money Your House House Ltd.

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