Garage foundations.

[Ashnook.]

I have planning permission to build a double garage in my garden and I am looking for some advice regarding the foundations.

I am hoping to get away with a 1M deep strip foundation but there is a hedge on one side so I assume I will need to go a bit deeper on this side.

The bigger issue, though, is that a sewer pipe run under where the garage is to be built and this will likely clash with the foundation concrete. I would rather not move the sewer pipe. What are my options?

Can I run the foundation concrete round the pipe if I somehow line the outside of the pipe so as to leave a gap for the pipe to move within the concrete? Would this be allowed and would this work? I know I have to get the building inspector involved at some stage but I want to do a bit of research first.

If this is not possible then can I build a raft foundation slab instead and build the garage in this slab?

Or what other options do I have?

Thanks, Brian

[dg]

Does this garage require Building Regs approval?

If not a shallow trench or a raft would suffice. A raft may be better to overcome the drain problem

If it requires approval, then your options are more limited. But generally, you would bridge over the drain, and would take the foundations down to a teast the invert level or 1000mm.

If the drain is a public sewer, then you also need your water authority's permission

dg

[Steve Walker]

Ashnook."

[Ashnook.]

I don't know if it required building regs approval, I just assumed it would.

Bridging over the drain means having no foundation concrete under the sewer at that point?

It's a sewer pipe from some adjacent bungalows that runs across my land.

[Hugo Nebula]

On Wed, 19 Dec 2007 07:29:24 +0000, a particular chimpanzee, "Ashnook." randomly hit the keyboard and produced:

If it's detached, less than 30m², and either substantially non-combustible or more than 1m from any boundary, then it's exempt from the Building Regulations.

No. You have to continue the foundation under the pipe. See Diagram

7 of Approved Document H It's a sewer pipe from some adjacent bungalows that runs across my land. That doesn't make it a public sewer. If it's a drain serving more than one property which was in place before 1937, then it's a de-facto public sewer. Otherwise it has to be adopted and shown on the Public Map of Sewers. If it is a public sewer, then you will need the Water Company's permission to build over irrespective of whether you need Building Regulations or not.

[Ashnook.]

Thanks Hugo, very helpful.