Loft conversion - storage - permitted development

[JP_]

Hi

Just been reading up on permitted development for loft conversions, i.e. 50 m3 allowed for semis.

To be permitted development any additional roof space created must not exceed these volume allowances:
• 50 cubic metres for detached and semi-detached houses.

Two questions:

1. Does the 50 cubic metres refer to additional space, is in a dormer, or additional living space? I assume the latter, because that would be a massive dormer if 50 m3

2. If the latter, does this include all space or living space? I might consider one large room with storage room (just boarded out loft space) for the remainder, if I do not need planning permission.

If it means additional structural space, then I guess I am good to do a full loft conversion without the need for planning - it will be rear dormer + a few Velux on the side (and neighbour on that side has no windows themselves)

 

[Nakajo]

It's the additional volume provided by the extension.

Measured on the highest and lowest points of the existing roof slope of a typical terraced property, this would equate to a dormer measuring not more than 3.6m deep by 2.7m high (so maybe 2.8m as measured from internal FFL) by 5.1m wide, say.

 

[JP_]

Thanks.

50 m3 is really big isn't it? When would a loft extension ever need planning permission? That would be a huge lump on the side of a house wouldn't it?

Anyway, sounds like time to call an architect!

 

[freddiemercurystwin]

Architectural technician not an architect.

 

[JP_]

Ah, I see, does not sound so big when you say it like that.

I assumed the additional volume would not include the original space within the roof.

e.g. a dormer that is 3.6m deep by 2.7m high by 5.1m wide would be 49.5 m3, but about half of that volume is within existing roof isn't it?

I guess they go by floor area volume x height within the new constructed part?

Still sounds like plenty for our needs,

Thanks!

 

[Nakajo]

Apologies - you're right. I need more coffee. I've doubled the volume by mistake ! Yeah, loft conversions on unlisted homes, and homes not in conservation areas can be crazy huge.

 

[tony1851]

Architectural technician not an architect.

Plus an SE for some numbers on the beams, perhaps?

 

[JP_]

Hi,

Yes, both of those - by "architect" I meant it all!

Are there any free online sketchup tools available? I tried a couple of downloads but too steep a learning curve.

I was the plan the design myself to start with, to save time with the architect. Trying to work out where the stairs will go. If we extend the current ones they are right in the middle of the loft space which will be a bit annoying.

Got an annoying shaped roof. Hang on, I could probably show you ...

Ok, that took a while. Just "designed" my loft, version 1.

Untitled

• JP_
• 12 Feb 2015
• 1