We are looking at a house next week, which we’d want to extend if we bought it. It currently has a narrow flat roof extenstion on the back and we’d want to make it bigger as in the image below. As we havent even looked at the house properly yet, I’ve not done too much digging but I think it would fall into permitted development, but would need to go through the party wall act notice. Does anyone with a bit more knowledge know?

Also the existing extenstion has a flat roof and I hate flat roofs, so I was wondering about if we got that far having a pitched roof put on it. I struggled to work out if this would mean it needed proper planning rather than permitted development?

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I think, because you’re up against part of the neighbours garden, it’ll be a full planning application as stuff like light reduction to the neighbours needs to be considered.

Not sure about the permitted development but I’d def go with a pitched roof with a couple of velux in.
Just be aware that sometimes it’s better to take down the existing extension and rebuild from scratch…. You may even be able to go a bit bigger.

@lovewookie – It says you can go right up against so long as eaves are no more than 3m – which is why I think it might have to be a flat roof

Thanks Sharkbait. – yes that would be the hope

The online guide is a good start: https://www.planningportal.co.uk/info/200130/common_projects/17/extensions

As above i suspect the 3m limit will be the killer. Also, check that you actually have PD rights, a lot of properties don’t. Finally, a modern flat roof can be very good. 25 year guarantee, should be fine. Also gives you have the option to have a green roof which is a great addition, especially in an urban area

there’s a few places round here have single story extensions with shallow-pitched tiled roofs, I guess to get under the 3m limit. It is possible, depending on the width of the extension

Also you might be able to do it without eaves on the side, in fact I think you might have to as you won’t be allowed to over sail their property if you want the wall right on the boundary. A little parapet wall on the side then eaves on the bottom (lower than 3m)

The depth limitaitons apply from the original rear wall and if the depth of the existing extension is between 3-6m it can still be permitted development, however only if you provide prior notice to the Local Planning Authority.

our ex neighbours did this to us, they stayed 1m from the boundary out of courtesy and so not to block the light to our window.

You would generally need a meter or so space to build it and for future access, unless your neighbour allows your builder to work in and access via their garden(not likely)

I don’t think ‘permitted’ includes extensions(I’m in Scotland) but I may have misunderstood, ‘permitted’ would apply to changing the roof? I’d email them to get that in writing and you can check on what planning consent you need at the same time.

There are ways of building up to the boundary edge but it’s not popular with neighbours and a big source of falling out, looks like a full planning application to me, which if objected to means another, always, always best to speak to your neighbours about things before they get a letter both shocking them and asking for their permission…it’s almost designed to get an objection.

I don’t think ‘permitted’ includes extensions(I’m in Scotland) but I may have misunderstood, ‘permitted’ would apply to changing the roof?

It does cover extensions. -well it did last year

In Scotland if going to the boundary line you need full blown planning which adds significantly to the cost. – was flat fee for the building warrent but to go planning was a %age of the projects standardised cost

I could not modify the existing roof line when adding a 7*3m permitted development extension because it meant changing the party wall and that pushed it out of permitted development.