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Extensions

Building on top of a retaining wall

Anonymous user 09/03/2024 - 3.12 PM

Hello Everyone, The house we’re in has a retaining wall running down the side of the entire length of the front and rear sides of the house. It was clearly put there to retain soil at the side where it’s a public woodland footpath. The retaining wall is 2.5m tall from the ground up. We’re now wanting to build out from the side of the house and were wondering if the retaining wall (which is double bricked width) could be bricked onto, to form the base of the extension. Some questions ....... could a breeze block wall be placed in front then of the whole new side wall extension to give insulation and then skim over? I’m wondering about moisture entering through the current retaining wall part as it’s purely clay and soil sitting behind it? Any thoughts would be appreciated. Thanks again

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4 Answers

Seamless Construction Limited

Rating: 5 out of 5
Market Drayton
The retaining wall would have been put there to retain the ground against it. So I would have thought it would have been designed for lateral force. By increasing the height of the wall above the retained soil, could add more lateral force with wind etc. You will also have the issue of damp penetrating's the wall. You will need a structural engineer to check and calculate what you have there and advise. Thanks Mick
Answered18 July 2020
17

Anonymous user

A test hole will have to be dug along side retaining wall to find out if foundation is strong enough to take extra weight
Answered21 July 2020
1

Anonymous user

Hi the wall was only built to hold back the soil, not as a load bearing wall. And will only have a shallow footing and foundation if any. And if your building a side extension, even though it's not load bearing, a 1 meter by 600 foundation is needed, and I'm sure building control will want to check and see the footing before any building work is carried out, and I'm sure the architect will have in his notes on the drawing plans, that the footings and foundations will need to be exposed before work moves forward. Get this wall checked, but to build on it or off it would not be a good idea, and depending on how log ago it was built, before building Regs come along I've seen side walls built on belly down bricks. I hope this helps
Answered16 August 2020
1

Anonymous user

You will also need to check depth of existing footing to make sure it will take more weight dig an inspection hole so you can see that you have enough depth of concrete under existing wall and ground is good also might need to dig trench on out side of wall to make sure you have a waterproof membrane on what will be outside of wall so you do not get ingress of dampness into new building
Answered13 August 2020
0