Bridging Underground Soil Pipe with Trench-Filled Foundation

30 May 2013
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United Kingdom
I have an existing soil pipe passing through the intended location of the foundation for my extension. We are going to use a trench-filled concrete foundation, and I am unsure of the usual method of providing the necessary protection and clearance for the pipe. I have seen diagrams showing blockwork and small lintels used where the pipe passes above the level of the concrete, but not where it doesn't. Are there any proprietary systems available?

The trench will be 1m x 600mm and the pipe is about 600mm down.
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Just in the process of doing similar - building inspector has said to just lintel over where the pipe is. Also said he was happy for us to place footing as close as we liked to either side of the pipe but we will leave a reasonable gap just to be safe. You'll have to check with your local water authority for their build over criteria - we are with Anglian water and their criteria are on their website.
Just in the process of doing similar - building inspector has said to just lintel over where the pipe is.

I can't see how that can work: when we pour the concrete it will cover the lintel and the space beneath it, and encase the pipe completely. Surely we need to shutter out or box out a space all around the pipe using a material that wont collapse under the weight of the poured concrete before it goes off, extending completely to the sides of the trench, so that the concrete doesn't run around it and defeat its purpose?
yep as I understand it you shutter off the footings either side of the pipe and pour your concrete so that it doesn't go near the pipe and the lintel then bridges the gap. Thats how I've understood it - I could be wrong but thats why I'm paying someone else to make sure its done correctly!!
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We will shutter stop each side of the pipe and lintel over if we need access to the pipe later on.

Otherwise B.C. will usually accept the pipe being wrapped in compressible material i.e. glass-wool insulation.

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