Knock down or upgrade extension and the 1 metre planning rule?

Hi Everyone,

Bear with me while I try to explain the conundrum...

I am considering a home extension on a house I bought earlier this year. The extension already has planning permission. The house currently has a single garage with a workshop behind it which are currently joined to the house by a temporary ‘indoor/outdoor’ area with a (leaking) polycarbonate roof and basic stud wall to the front. All in, the area is around 5m/2. The planning permission is to keep the existing garage and workshop structures and upgrade the roof to a larger pitched roof (creating a bedroom in the new roof space) and to upgrade the front wall. The two builders I have had round to estimate think it’s easier to knock down everything and start from scratch as the external walls will need to be upgraded and they’d rather do that than underpin the walls and add a second skin to them. My question is, if I demolish and rebuild the external walls is there a rule whereby I would then have to bring the walls in 1 metre from the boundaries? The external walls are currently almost right up to the boundaries on two sides so this would make the whole extension much smaller (and probably not worth doing). Would I have to re-apply for planning to demolish it all rather than upgrade the existing structures, even if I am keeping the area of the new extension exactly the same?

Can anyone help?!

If you knock down everything and start from scratch, you would need planning permission for what you propose; this applies even if you are building on the same footprint.
There is no specific 'rule' that the new build must be 1m from a boundary, unless it is a policy set by your local planning authority.

Just thinking out loud really. I wonder, if the proposed rebuild was going going to look exactly the same as the upgrade scheme that received planning permission whether demolition and rebuild could be treated as a non-material amendment to the original application?

With the best will in the word, sometimes walls just fall down. If you do go ahead and tear it all down and then rebuild in facsimile, I can't see how that would be a problem.

Considering a planning application doesn't have to identify the demolition works, it just shows before and after (existing and proposed) - then the main thing is you need to end up with what has been approved. I can't see how you can be in breach of the planning permission as long as the end results matches the approved drawing.

(assuming you are not in a conservation area or a listed building)

Clearly I'm in a minority of 1

Thanks everyone! I think I’ll have to call planning, it could be that I can get a non-material amendment to allow the demolition as I would be replacing like for like - the granted permission only says upgrade the roof and front wall so it may not be possible. I’ll update this thread as and when I get anywhere with this. It’s Bristol planning so I might be a while

In planning rules, the "1m from a boundary" only tends to apply to first floor extensions, and only if there is a specific planning policy rule that the local council says it will apply to specific situations.