Original size of the house

[Kmward36]

Hi everyone

we want to build a double extension on to our semi detached home. Regulations say it can be no bigger than 3m from the back wall of the house….but we’re having problems Decided what the back wall of the house is.

house was built in 1860 and the back of the house is a L shape. Would back wall of the house be the end of the L or the other wall?

not our house but a similar house

What council are you? Are there no FAQs for that sort of thing? If not I guess you’ll need to email them and get clarification. Or would a local builder know, you could ask as you get a quote.

Email the planning dept of your council and ask them?

I don't know, but what do you use a 3m wide room for? As in, is it worth it to gain a small space? Or is it worth going for planning to get a bigger size?

Thanks everyone, I have emailed the planning department and they’re coming out but the earliest they can do it in 8 weeks time. We were just curious if anyone knew.

We are hoping for bigger than 3m but it all depends on what they say the back wall is.

do you mean you can do 3m under permitted development, if you want more space you can go for planning permission?

Where's your back garden in relation to road? The back wall would be one that's parallel to the road your house is on. If you're on a corner, the road that the front door is on. Also would depend on where your neighbours house is in relation to yours. I think the 3m rule applies so you're not too far back in relation to your neighbours- as the Xdegree rule (can't remember what the number is) will apply to any windows etc you'll need to put in, in relation to your neighbours windows/access to light.

It depends if there is a maximum development size, that may be from the original house. But if the last extension was a really long time ago that might not count.

I think you're talking about under permitted development?

There's a document which should be helpful - Permitted Development Rights for Householders - Technical Guidance.

It has lots of diagrams showing various scenarios.

Without seeing your actual house and its location I can't be certain but in your example the below would apply.

P.15 defines the front of the house - in your case both sides of the inside of the L

P.17 states 'the rear wall or walls of a house will be those which are directly opposite the front of the house' so in your case both rear walls on the outside of the L

'original dwelling' in planning terms means as it was in 1948, or if built after then, as it was originally built.

The Technical guide referred to above gives details on where the measurements need to be taken from in order to meet the requirements of permitted development.

If you can't meet pd requirements, or want something bigger, you need to make a full planning application. It doesn't necessarily mean that want you want can't be done.

https://www.gov.uk/government/publications/permitted-development-rights-for-householders-technical-guidance/permitted-development-rights-for-householders-technical-guidance#class-e-buildings-etc
Document here

Lots of things! We did a 6x3m onto the back of our house, knocking into the existing kitchen and dining room and made a massive space.

You knock through. Turning a 5x3m living room into a 5x6m room makes quite a big difference to the usable space, and isn’t ridiculously expensive.

@Cheeesus and @Saschka I was thinking about the 1st floor, it isn't big enough to add a bedroom. I understand the idea pof making bigger living spaces downstairs, but It doesn't seem much sense upstairs?

3m wide is plenty big for a bedroom? But also you can knock through upstairs too.

I know you can knock through. Ans yes, you can fit a bed in, but I still think it's a lot of expensive work for a narrow space.

Say 4x3m is a reasonable size bedroom though?

We only have a downstairs bathroom at the moment so we’d use the space upstairs for a bathroom (well that’s the plan anyway!)