Outbuilding maximum area

[Anak]

Hi all,

Hopefully a quick one for the experts. I am looking to build an outbuilding in my garden, this will be wooden construction, close to the boundary.

From my understanding, the limits are 15m2 area and 2.5m height.

Am I correct in thinking the 2.5m is from the current maximum natural ground point, so if on a slight slope I take the highest point and measure up 2.5m, I can then then run level from there.

Is the 15m2 internal volume or external?
Do overhangs count, as I am currently thinking of having a reasonably sized overhang on one of the sides to provide cover for a wood store (this may or may not require support pillars - I've not thought that far ahead yet and don't know if it makes a difference w.r.t. the rules).

 

[magicmushroom666]

The 15m2 is internal, had that confirmed by my local authority. Not sure about the overhang though.

 

[DevilDamo]

You are confusing Planning and Building Regulations as there are different rules to both. The height is Planning (Permitted Development) related and the internal ‘area’, not volume is Building Regulations related. You can find advice on both here...

https://www.planningportal.co.uk/info/200130/common_projects/43/outbuildings

https://www.planningportal.co.uk/info/200130/common_projects/43/outbuildings/2

 

[Anak]

Thanks, but I've read both those pages and mostly understand the limits, as stated in my original post.
My question still stands - would any external overhang of the roof count as part of the 15m2 floor area or not, as I may add a 1m overhang on one side which would add 3m2 to the roof area (but obviously nothing to the internal size).

 

[tony1851]

If you were just talking about normal projecting eaves, then that would obviously not be counted as part of the floor area of the building. However, as your projection is about 1m, and is serving a practical purpose, ie wood store, then I suspect some inspectors would count that as part of the total floor area.
I suppose it depends on the individual inspector's interpretation of the rules?

 

[DevilDamo]

It’s normally the internal floor area and that of a habitable space so an overhang should not be included. Similarly to that of an open porch that would not require BR’s. Although not 1m, I’ve had 600mm overhangs with no issue from Planning or Building Control.

 

[nickjb]

If the overhang becomes large enough to be counted as a veranda then it may planning permission, although I think that is more down to floor and if it is raised

 

[tony1851]

It’s normally the internal floor area and that of a habitable space so an overhang should not be included. Similarly to that of an open porch that would not require BR’s. Although not 1m, I’ve had 600mm overhangs with no issue from Planning or Building Control.

I suspect here it might be a matter of degree. At what limit would you say projecting eaves would not count? Structurally, you could have a 15 sq m. enclosed building with flat eaves on one side cantilevering 2/5/10m, with the far wall well-anchored down; I suspect Building Control would want some input into that.

 

[DevilDamo]

I think @nickjb is right as the PD definition of a verandah is...

“A veranda is understood to be a gallery, platform, or balcony, usually roofed and often partly enclosed, extending along the outside of a building at ground level.”

There was also a thread questioning a verandah back in 2016...

https://www.diynot.com/diy/threads/veranda-permitted-development-query.458275/

It therefore appears a verandah would be that which included a raised platform along with a covered roof over!?!

As for Building Regulations, it may be on a case by case basis and whether it boils down to if this ‘overhang’ requires additional support via columns for it to not be considered as such? But even a canopy with columns wouldn’t require BR’s.

 

[^woody^]

My question still stands - would any external overhang of the roof count as part of the 15m2 floor area or not,

Read your own post. Concentrate on the "roof" and "floor area" bits.

When was the last time you heard a carpet salesman ask how big the roof is?

 

[tony1851]

would any external overhang of the roof count as part of the 15m2 floor area or not,

The world and his wife can debate this until the cows come home; why not just build it - with your canopy - and without bothering Building Control?
(As it's timber and within 1m of the boundary, you do need to keep the internal floor area to <15sq m (it's a fire reg.)).

Unlike DOH and Woods, my opinion is that it would technically require Building Regs approval. However, on planet earth away from the legal ins-and-outs, the chance of anyone from the council picking up on it is pretty well nil: just build it as you want and stop mithering us

 

[^woody^]

Unlike DOH and Woods, my opinion is that it would technically require Building Regs approval.

What for? The floor area is the criteria

 

[tony1851]

What for? The floor area is the criteria

I was merely looking at the other exemptions such as 'conservatory, porch, covered yard or covered way', all of which are still area-limited for exemption,
and applying this to the OP's position.
But in the big scheme of things, it's not going to be an issue for him.

 

[Anak]

Thanks for the various replies, I'll just crack on and see how it goes.
Clearly though it's not that simple considering the numbering of differing responses...
I guess at worst they say it is too big, in which case I add some more pillars run a saw across the top and now it is a separate free standing structure...unless there is something else I've missed.

 

[oldbutnotdead]

You'll only come unstuck if your neighbours dob you in (which they're unlikely to do unless you build a really ugly shed and/or do the noisy jobs late at night/early in the morning).
Your woodstore overhang thing is a bit of a grey area- I suspect that if you keep the overhang small enough (say 600 or 700mm) then if planners did pay you a visit it would be hard for them to argue that such a small space could be used as a veranda. The bigger the overhang the more scope for argument from them... and 600 would be plenty for seasoning timber for a large woodburner. Long as you aren't anywhere near the 50% of original garden rule you'll be fine