Bridging over private drain in corner of foundations

[jhfw2023]

Hello. So currently I am excavating the foundations for a cavity wall garden office. Unfortunately my drain pipe runs at an awkward angle at the corner of where my foundations would be.

My initial thought was to excavate the foundations deeper and pour the concrete below the pipe, and then bridge over with lintels in the brickwork. But due to being a corner, I thought to get some outside advice also.

Any suggestions would be appreciated.

 

[noseall]

My initial thought was to excavate the foundations deeper and pour the concrete below the pipe, and then bridge over with lintels in the brickwork.

Correct.

It's just unfortunate but it does happen...

Big Trench

• noseall
• 12 Jun 2020

 

[jhfw2023]

Thanks Noseall. Also, as the pipe would be in the sub base for my floor slab, would I fill around the pipe with pea shingle, and then be fine to put MOT type 1 compacted over the top of that?

 

[noseall]

Thanks Noseall. Also, as the pipe would be in the sub base for my floor slab, would I fill around the pipe with pea shingle, and then be fine to put MOT type 1 compacted over the top of that?

We tend to pack glass-wool insulation around the pipe if it passes through either the foundation concrete or the masonry. Retro-pack the insulation, if it passes through the masonry - i.e. after you have built around and lintelled over. Make sure you have decent clearance around the pipe.

In that image, we felt the pipe was too low in the foundation concrete to do anything other than protect it with a shutter. It has clearance above it, whilst sitting on a bed of pea gravel (up to the pipe equator).