Extension - confused about planning. What do I need to do?

[IHeartKingThistle]

We are in the process of planning an extension off the back of our (attached) garage. It will be angled - imagine a square with a big corner lopped off.

I am pretty sure that even the longer side is well within permitted development, especially now you are allowed to come out even further.

Do I need to check this? Who with? Can I just merrily start building?

I should check with your local council's planning dept. The contact details should be online.

For permitted development you can get a certificate of lawfulness from the council, costs about £80 - 90 ish.

Not sure what happens if you start building without one, but you can also get them retrospectively.

It might be within permitted development but you will still need to comply with building regs, so although in theory you can start right now, someone would need to come out a check foundations etc then at interim points then at the end - if you call them out too late they can make you "undo" stuff so they can check - so they could dig down to look at foundations or get you to hack plaster off to check rsj.

Check with the council. If you are in a conservation area, green belt or area of outstanding natural beauty then the planning constraints are different.

Thanks so much, this is so helpful. Our council won't give an 'informal' opinion over the phone unfortunately, everything has to be submitted. Think I might phone the building control department tomorrow.