Convert lofty room into two floors - regs ?

[SimonH2]

Just starting to look at options for an extension with a friend - it's really only at the "what can we do" stage so far.

It's a 1960s end of terrace, with not a lot of room, and the extension would be close (~1m) to the side boundary with the semi bungalow next door. There is an existing outhouse attached to the house, which as far as I can make out was built at the same time - it's on the 68/69 OS map, along with those of the neighbours, and the houses weren't on the 50-something map. The intention is to replace the outhouse, something like 2.5m wide and perhaps 4m long, possibly making it a little wider (at the same width, the current kitchen doesn't really allow for two people to pass easily !)
She's just looking at a single storey for larger kitchen and downstairs loo. I'm thinking there's scope for a larger bathroom upstairs and more storage.

The plot is outlined in blue, the outhouse in red in this plan. North is up.

Untitled

• SimonH2
• 20 Sep 2013
• 1

The terrace that's 'back to back' with this one is higher and looks down into the garden.

I've a fair grasp of PD, but I have several questions I haven't found answers to :

The back garden is sloping (up and away from the house so giving more height available) - allowing for that I reckon a quite high single storey extension could be built. But it would be outside PD limits for a 2 storey - would be less than 7 meters to a boundary from the rear elevation. Is planning required to add a floor to convert a lofty single storey into 2 floors (the upper one would have to have a vaulted ceiling) ? If planning isn't required for the internal conversion, then it would be one way to get a 2 storey extension.

Related to that, at what stage could the conversion start - when BC issue the completion cert, or some other time ? In particular, it would be nice not to have to completely finish the kitchen before starting work on the upper floor ! I had in mind getting the floor in, making a temporary bathroom downstairs, doing the new bathroom upstairs*, fitting out the downstairs as a kitchen, removing the current kitchen, and opening up the current kitchen space to be part of the dining room.
* Access to the upstairs would mean removing the current bathroom, leaving insufficient space for anything other than some much needed cupboards.

And to what point is the eaves height measured ? The very edge of the tiles, or something else ? It's critical as this would be an "every inch matters" job. I'm assuming having 2 foot of soffit to bring the eaves down might be frowned upon !

Does the rear wall of the outhouse count as "the rear of the original house". The plan isn't to extend much (if any) past it's back wall, but more than the 3m permitted by PD if measured from the main house. The outhouse is attached to the main house by one wall and the cast concrete roof - so stepping out of the back door from the kitchen, there's a gap to one side round the side of the house, and the outhouse directly opposite.

Lastly, leaving aside the practical issues of underpinning the house foundations, would there be any restrictions digging down to make a cellar ?
While it's a lot of work, it would help offset some of the lost space from removing the outhouse.


Or do you think it would be worth having a go for a planning application for a full 2 storey extension that would be barely outside PD limits apart from the pesky neighbours garden "stepping in" on this one ?

 

[SimonH2]

OK, guess it's come under TL;DR for people

Shorter version :

1) If you have a space with lots of headroom, does it need planning to add a floor and make it two smaller spaces ?

2) If an outhouse was built at the same time as the house and is joined to it, does the rear face of that count as "the rear of the original house" ?

3) Are there any restrictions in going down (ie digging out a cellar) as part of an extension ?

 

[munchingB]

basically sounds like you want to build something with planning permission or permitted development or under building notice but that you want to build a whole bunch of other stuff after or during the 'official' initial build?

youre asking if you can build 1 thing and build 10 other things instead?

why dont you just get permission or buy a building notice of everything that you intend to do?

 

[big-all]

permitted development
must be single story

any height is taken from the heighest point it covers
if you wish to alter it later its a change that must be within permitted development

 

[SimonH2]

basically sounds like you want to build something with planning permission or permitted development or under building notice but that you want to build a whole bunch of other stuff after or during the 'official' initial build?

youre asking if you can build 1 thing and build 10 other things instead?

Not quite. What I had in mind is very, very nearly within PD limits for a 2 storey extension - 3m to eaves, 4m to ridge, etc. But for a 2 storey there's a limitation of 7m from the rear face to a boundary. If it were the next house along that would be fine, there's more than 7 m to the back of the garden - but there's a "corner cut out" that's the back of the neighbours garden and that's only a couple of m away.

Other than this 7m rule, I can't see any significant difference in size limits between single and 2 storey PD.

Where on the eaves would the hight be measured to ? Bottom of fascia ? Top of Fascia ? Bottom edge of tiles ? Something else ?

permitted development
must be single story

It would be, initially.

if you wish to alter it later its a change that must be within permitted development

Does that include completely internal alterations - it would be much the same as adding or removing an internal wall, just on a different plane.


I am inclined to apply for planning - stressing that the envelope is near enough within PD limits (I'd go for slightly higher if not constrained by PD) - and see what happens. I just wanted to explore whether it could be done under PD which obviously makes life easier if the planners can't block it if they decide to be fickle.

 

[sleeper341]

OK, guess it's come under TL;DR for people

Shorter version :

1) If you have a space with lots of headroom, does it need planning to add a floor and make it two smaller spaces ?

2) If an outhouse was built at the same time as the house and is joined to it, does the rear face of that count as "the rear of the original house" ?

3) Are there any restrictions in going down (ie digging out a cellar) as part of an extension ?

I'm no builder or BCO but I am building a single storey extension on my house and I had a similar outhouse which I have knocked down to allow me to extend the kitchen and put in a loo shower and another bedroom/office. In answer to question 2 - My BCO said that The rear face of the out house would not count as the rear of the original house because it was never habitable.

 

[cjard]

What would a bco know about planning? Their interest is how it is built, not where