Self-Managed Rear Extension

[Narthecius]

Hi all,

 

Thought I'd come to introduce myself. The project I'm doing isn't very exciting compare to some of the builds on here, but I'm very much looking forward to contributing to the community if I can (and probably asking for lots of help too!).

 

I'm in London and looking to do a smallish (20sqm) rear extension on my 1930's end-of-terrace house. I had a contractor quote for the build and we are in different worlds. Budget is ~£75k, but quote came in 130k all in, hence going down the self-managed build route. I am a competent DIYer and am able to dedicate some time to planning/helping, although I doubt I would be able/want to tackle the big stuff.

 

The property had planning permission in 2007 for a rear extension and I inherited all of the documentation for this when I bought the property. At that time the soil was surveyed and it was discovered that it was "made up" ground. Pile and raft foundations were recommended.

 

My first question - would the soil survey from 2007 still be useful? I'm guessing not much would have changed underneath the ground in the 16 years since the survey, although I could easily believe that piling technology has moved on. I can post the soil surveys (borehole & dynamic probing) here - is there a good place on the forum for things like this?

 

Thank you all.

[Narthecius]

Can move this elsewhere if it's better

DYNAMIC PROBING REDACTED.pdf SOIL SAMPLE REDACTED.pdf

[Jilly]

Welcome! As your planning permission has expired, it would be wise to check with your local authority if it comes under 'Permitted Development' or if you have to submit another application. It gives you a chance to tweak the drawings to something you like. 

You will need to also submit building regs drawings and will need a structural engineer to design the foundations etc and they will need the soil surveys for that. Hopefully they will be happy with what has been done, but in theory could ask for more.

[Narthecius]

Thanks Jilly. I believe I will need to follow the "Prior Approval" permitted development route, because I'd like to go out 4m. I will start with getting the drawings done!