Extension Drains

[ianm75]

I'm building my extension and sink waste and WC waste will pass through the foundation trench. The foundations are to be dug 1m deep and 600mm wide . The waste's however are only 1 foot under the ground so they will be 2 foot from the bottom of the trench.

I have been told by 2 people how to prepare the drains before pouring the concrete and i just want to make sure which one is correct or if both.

1 - Wrap the pipes in an material that will mean them to expand withing hte foundations.

2. Lintel over the pipes

Can anyone expand any more on the above options, like what material i could use to wrap around the pipes and secondly how do i lintel over the pipes when they cut through the foundations approx 2 feet from the bottom of the trench?

Thanks in advance

 

[^woody^]

Drains don't "expand"

Rather the new building may move, so you need to allow a gap around the drains so that any movement does not contact the pipes and crack them.

Leave a 50mm gap. You can fill the gap with sand or a compressible material like cardboard

You either put some formwork around the pipe before concreting. Or step the concrete at the top of the drain and then lintel and brick up over it

 

[noseall]

similar situation here

 

[ianm75]

thanks noseall and woody