We have a flat concrete roof covering our doorway, which was boxed in (badly) with PVC windows and door by previous owners to create a porch. It's in dire need of repair. It isn't insulated, has a drainpipe and drain running through it, and lets in vast amount of water in rainy periods.
The concrete flat roof is part of the house, and all the houses on our road have either the same flat roof or have boxed it in.
We want to stick a small pitched roof on the porch (with a skylight) and box it in using brick.
My problem is that the flat roof, which juts out of the house, has a footprint bigger than permitted development 3x1m (something like 3.7m x 1.2), so not sure if the boxing in would need planning permission.
I have no idea if the existing mess of a porch complies, but it's been there years and we haven't had any death threats. From ancient Google maps images, the travesty we have was put in about 2011 and replaced something very similar.
It's a 1950s ex-council semi and not a listed building. Our builder will do the walls to building regs so we'll lose a bit of space for bricks and insulation etc, but has said that we don't need planning permission. (He's said that it would be new for old - which feels it would be a bit wobbly if the council challenged us.) We trust our builder, though - he's family.
The pitched roof won't exceed the 3m from ground level so my real question is if we need planning permission to replace what's already there if the footprint of the concrete roof is bigger than permitted development?
(The concrete is knackered so we'll technically be pulling that down and starting from scratch - would that make a difference?)