Depth of foundations required on existing footprint of conservatory

diystarter7

Phone your local council and speak with the duty planning officer. Often very helpful and free guidance.

Woolsery

diystarter7 said:

Phone your local council and speak with the duty planning officer. Often very helpful and free guidance.

Might not be free now. Even generic questions cost £30 where I live, and I mean stuff you could Google. This is with a council that's generally helpful.

I've done something similar on an old conservatory base and agree ground conditions are the key thing. I was told all sorts of things, but an experienced builder assessed things at sub soil level and advised I could undercut and reinforce rather than start again, so that's what I did, saving on demolition and disposal. That was a considerable time ago and nothing has moved, so he was correct. Floor had to go though.

DRP

1. Speak to your designer / architect. They will have good knowledge of foundation requirements and will have an idea whether it is possible (your footings sound more substantial than mine, so hopefully ok).
2.  Have the plans for BC submitted with a statement like "Use of existing foundations to be confirmed by

Building Control Officer. See attached notes and photos of existing foundations.
3. As soon as you've submitted the plans give BC a ring and ask them to come and inspect. They should give you an answer there and then.