Foundations

[burygas]

Hi
I am planning a single storey extension on my bungalow.

I have very stable ground (clay) from around 200mm below top soil.

I know you need a minimum 900mm trench,is this from DPC or the actual depth of hole.?

The bungalow was built in the 70's and the existing footing is 900 from DPC.

Also can you build over the soil pipe.???

Thanks

 

[tony1851]

It's the depth below ground level.
You can build over a drain pipe if it is suitably bridged.