Workshop shed planning permission

[MikeG.]

What the buildings are made of is almost entirely irrelevant. Other than in certain designated areas (including national parks) you can cover up to half of your land with outbuildings (so long as they are behind the front of the house), without Planning Permission, so long as each individual building falls within the various dimensions given for Permitted Development. I would always advise clients to separate the two buildings, even if by only a few inches, such that they could never be construed as one.

The 7.5 x 4 m workshop was obviously given as an example such that it falls outside the purview of Building Control. Please note that this is determined on internal floor area, not the footprint, so you can actually build slightly bigger than the suggested size without needing inspection. On a practical note, I would suggest going for something slightly wider than this, and shorter if necessary to compensate. Planning a workshop is just easier with a wider space. 4.8 metres roof spans are easily achievable with standard timber sizes, but over that it gets a bit more complex, so I'd suggest heading towards that dimension for your width if that fits with the area you have available. With about 150 for wall thickness, that would give you an internal width of some 4.5m, which would lead to a max. length of about 6.6 metres.

However, as I've said previously, if you use blocks for your walls you'll end up wasting a lot more space because you'll then have to add insulation. Timber frame produces a much narrower wall.

 

[gwr]

Mike that is exactly the type of info I was looking for and it's much appreciated. I did look at eternit cladding and think it would look better but I keep going back to block for several reasons but could be totally wrong in that respect.

I feel block and dashed just seems more secure, I know the main entry points would be doors and windows and if they want in they will get in. Also trying to keep the noise to a minumum is a concern I just feel block with timber stud full of insulation it will help more so than timber frame but I could very well be of the mark.

An interior size of 4.5 x 6.6 does seem a more useful space and is doable with the space I have thanks for pointing that out.

The builder can't start until late may early June so I still have time to make any small changes.

 

[MikeG.]

You're choice entirely. I would just say that I have never known a shed broken into via the walls. It's almost always the door, and very occasionally the window. And of course, there is no reason at all why you can't have a rendered timber frame workshop (my last one was exactly that). You just need to design in some airflow behind the render, and that is easy.

 

[dom68]

hi can anyone tell me if any overhang on the roof will count towards how close the building is to the boundary or is it just the base of the building?

thanks.

 

[MikeG.]

Yeah, it counts. Even the gutters do.

 

[Miffer]

Just a quick question if you don't mind. With regards to building regs I want to build a workshop and gym that will be approx 7m x 6.8m so will fall under building regs, I'd rather it not so could I build it as two separate buildings but only a couple of inches apart to get around the building regs and then at some later date join them together after getting photographic evidence that they were indeed two separate buildings when built?

Cheers,

Brian

 

[MikeG.]

The standard answer is to build them as 2 separate buildings, as you suggest. I wouldn't suggest ever connecting them, as you never know......

Just a tip, about those dimensions. It is best to try to keep outbuildings down to under 5.1m in width, particularly because that is the maximum length of readily available timber (longer is generally scarcer or special order, and more expensive), but also because big spans produce big rooves, which can be ugly, and are generally expensive.

 

[Miffer]

Thanks for the advice Mike. I'm stuck with having to do it as wide as that because I'll dividing it down the middle, gym one side and workshop the other I need access doors for each on the front, the gym side will be too close to the fence and to be honest the workshop will be even though I'll have a bigger gap but getting machines and timber in would be a problem at the side.
So each side of the building is only going to be 3.4m wide with a pitched roof across that width supported by what was going to be a centre dividing wall which might be the outside wall now!

 

[jacko]

I'm liking the concept of 2 separate sheds to sneak under the 15m2 rule for building control.

Does anyone have any experience of what the requirements actually are for building control if you build within 1m of the boundary? The part that concerns me is the "constructed of combustible materials" which for timber frame sheds is definitely the case. I'm just wondering if it then goes into needing to withstand fire for 30 mins etc and needing special cladding or sheet material or the like for that.

In my borough, Greenwich, apparently you need to submit a Building Notice prior to work starting, with a £320 fee and plans attached, to start the conversation.

 

[MikeG.]

Masonry is of course fire resistant (bricks, block, stone). So is render (sand & cement or lime). There are cementitious boards which look like timber feather edge boards, and they're fire-resistant, (although you may need to provide the council with product information from the manufacturer). Windows aren't, whatever they're made of.

 

[devonwoody]

If the council get concerned re timber sheds near a boundary why is timber fencing no less a risk? :evil:

 

[MikeG.]

If the council get concerned re timber sheds near a boundary why is timber fencing no less a risk? :evil:

Years of experience has taught us, devonwoody, that fences catch fire rarely, and that buildings catch fire more often. You can't have electrical faults or store flammable liquids or gas in a fence.

 

[autotrans]

also permitted development

 

[Hobbo]

I'm really struggling to find a straight answer on the maximum size of an outbuilding under permitted development- all government and local council guidelines seem very vague with under 20m2 being ok, but 20m2-30m2 "probably ok".

The focus seems to be on maximum height and no more than 50pc of existing garden. If I'm looking to build a 7x4m timber framed workshop do I need permission?

Apologies if this has been answered elsewhere I couldn't find it!

 

[MikeG.]

It's not vague. "50% of the original land around the house" is very clear. You want to build 28 sq metres, so if you have more than 56 sq m of land around your house, you don't live in a National Park, AOB or World heritage Site, and if your permitted development rights haven't been previously removed, then you can build that (footprint) size without Planning Permission, so long as you then follow the further restrictions on eaves and ridge height, and location (back garden......but it's more complicated than that).

If you keep the building away from the boundary, you also won't need Building Regs approval (and by the way, you could go up to 30 sq metres internally without troubling the Building Inspector).

 

[Hobbo]

Thanks MikeG. I've read elsewhere and seen on Youtube that if I build next to the boundary (and I've got a typical UK garden so is difficult not to) and if I go over 15m2 I don't need to involve building control as long as it is 'not substantially made of combustible material'. Wood being a bit burny means although I'm under the 50% of original land and under 30m2- I'll still need to involve building control?

That's my confusion- planning portal is clear about height, square metres, percentage of original land, but seems vague around this point- I can't find a definitive answer.

I also don't understand why I can't have a veranda?! I'm planning to have a workshop with a really big overhang, sort of like a covered area sheltered from the sun and rain, definitely not a veranda.. ;-) has anyone got any advice on whether building control ever has an issue with a workshop having a veranda?

 

[MikeG.]

The reason for your confusion is that you are mixing up 2 entirely different elements.....Planning Permission and Building Control.

Planning Permission (your permitted development rights) is as I described.........it's about the size and height you can build without permission. WHAT you are allowed to build.

Building Control is about how you build your building. Different regime, different people, different rules. It is these people who are interested in whether your building will burn down and threaten the neighbouring property. If you keep 1 metre away from the boundary and under 30 square metres, then there are no building regs implications (other than the normal electrical safety ones). If your out building is under 15 sq m then there are no circumstances in which Building Control comes into play. If it is between 15 and 30 sq m, which is what yours is, then it is exempt from regs if more than a metre from the boundary, or, if it closer to the boundary than that, it is of non-combustible construction. (This latter point is almost always interpreted as "that wall closest to the boundary must be non-combustible, the rest can be anything you like", although sometimes it is "anything within a metre of the boundary must be substantially non-combustible, the rest can be made of anything you like").

If you still aren't clear, then why not post a quick sketch of what you are proposing, including your boundaries.

 

[Hobbo]

Ah, that makes sense. Ideally I'm looking to avoid building control, my previous experience with extensions ranged from really helpful to seemingly going out of their way to be bloody minded.

That also makes sense why some people are talking about building 2 separate outbuildings of 15m2 which I'm starting to prefer the idea of. Thanks for your patience!

 

[Hobbo]

Right, final questions on permitted development..

Can you sanity check my understanding here? If I wanted to build a workshop within 1m of my boundary, over 15m2 internal dimensions but under 30m2, with maximum height overall of 2.5m, and as long as I haven't gone over the 50pc rule- I can do this without involving BC as long as the party wall is 'substantially non-combustible'?

If the party wall is timber framed, clad in metal sheathing (same material as I'm planning for the roof), with rockwool or similar insulation and plasterboard instead of osb- would that count as non-combustible? Block or brick isn't an option for me unfortunately.

 

[MikeG.]

Yes, to all that, except it is only the outer face of the wall which needs to be non-combustible. You don't need plasterboard internally. Be a bit careful with "metal", because my understanding (and this isn't my field) is that aluminium can be thought of as combustible whereas steel isn't. I would check with the supplier. There are alternatives, such as cementitious boards (Eternit is one such) which mimic timber feather edge boarding, and are non-combustible. I think they're pretty cheap, too. The "substantially" part of the non-combustible phrase means that such items as gutters and rafter feet or fascias are generally excluded from the requirement.

The only other thing regarding BR you need to comply with is electrical safety, which will need testing and certificating by an electrician.