new shed advise

[jamie1976uk]

hi all

im planning to build a new shed on a triangular shaped area next to my house and im after a bit of advice. originally I was going to build the shed itself kind of a triangle shape with the end chopped off( I dare say there's a name for that shape),but the geometry involved in the roof was scrambling my tiny brain when I tried to draw it let alone build it, so im think of going for a sort a stepped design. I've attached a rough plan view to explain a bit better( the red line being the original shape ) the overall size it going to be 7m x 3m approx., and 2.5m high at the back wall sloping to the front. I'm planning on making the whole thing from timber frames and cladding in 15mm shiplap boards.

but Im starting to wonder if id have trouble with expansion/contraction though especially on the back wall. 7m x 2.5m is quite a big area and the longest shiplap boards I can find are 3m so there would be 2 joints in them butted together which im guessing would open up over time. does anyone else think this would be an issue or am I just overthinking it?

also, im trying to keep the cost down, so I was thinking of using 3x2 stud partitioning timber for any internal framework that shouldn't be exposed to the elements, but starting have second thoughts about that now.

thanks for any advice

 

[MikeG.]

The problems you identify as problems aren't an issue at all, but there are some issues which you haven't identified which could be important.

Shiplap is very much more expensive than feather edge board, but comes in lengths of up to 4.8 metres typically (up to 5.1 or even 5.4 occasionally). Feather edge board comes in the same lengths as standard timber, and from my local suppliers that is up to 4.8m in length, and is much cheaper than shiplap. Timber doesn't move along it's length. It moves across its width, and even if it did move along its length it wouldn't make any difference if there were none or 5 butt joints along a line......the movement would be the same.

You don't say whether you are planning to build using your permitted development rights. If so, and if your sketch is anything to go by, you appear to be covering more than 50% of the land surrounding the original house and therefore you wouldn't fit the criteria.

If you are planning on building hard up to your boundary (as again, it appears from your sketch), then timber board is not a suitable material as it is not fire-resistant. There are lots of options.

70x45 PSE (ex 3x2s) are OK structurally for such a shed as you propose, but are barely cheaper than 4x2s (95x45 PSE), and don't allow enough depth for what most would consider the bare minimum of insulation.

 

[jamie1976uk]

The problems you identify as problems aren't an issue at all, but there are some issues which you haven't identified which could be important.

Shiplap is very much more expensive than feather edge board, but comes in lengths of up to 4.8 metres typically (up to 5.1 or even 5.4 occasionally). Feather edge board comes in the same lengths as standard timber, and from my local suppliers that is up to 4.8m in length, and is much cheaper than shiplap. Timber doesn't move along it's length. It moves across its width, and even if it did move along its length it wouldn't make any difference if there were none or 5 butt joints along a line......the movement would be the same.

You don't say whether you are planning to build using your permitted development rights. If so, and if your sketch is anything to go by, you appear to be covering more than 50% of the land surrounding the original house and therefore you wouldn't fit the criteria.

If you are planning on building hard up to your boundary (as again, it appears from your sketch), then timber board is not a suitable material as it is not fire-resistant. There are lots of options.

70x45 PSE (ex 3x2s) are OK structurally for such a shed as you propose, but are barely cheaper than 4x2s (95x45 PSE), and don't allow enough depth for what most would consider the bare minimum of insulation.

thanks for the rapid response mike.

i did consider the feather edge boards but thought the shiplap would be more solid and last longer.

in terms of fire proofing, what would you advise? i think i read that you only need to take building regs into account if it was over 15m square, and i think my plans work out roughly 16m square, so would it be easier to reduce the size slightly?

the permitted develop rights issue, i do have a biggish front and back garden as well as a small area on the other side of the house, so if its 50% of the total land i don't think its an issue. or is it 50% of the land on that particular elevation of the house?

 

[MikeG.]

If you are over 15 sq m and within 1m of the boundary then Building Regs come into play. You could clad with render, cementitious boards (such as Eternit Boards, which look like timber cladding), and some sheet metal products. And no, I would generally advocate feather-edge boards over shiplap.

The wording is

No more than half the area of land around the "original house"* would be covered by additions or other buildings.

, and the original house is defined as

.... the house as it was first built or as it stood on 1 July 1948 (if it was built before that date).

I hope you've read the link in my signature.

 

[jamie1976uk]

im starting to think id probably be better off dropping the size slightly to get it under 15m sq, or making the storage on the end a standalone structure to bring the size down to avoid building regs. i'll mainly be using the for stripping down my mountain bikes etc, so there's nothing high risk going on in there so i think fire proofing it might be a bit extreme. im even toying with the idea of not putting an electrical supply in there. just getting solar lighting and plugging an extension into the external socket on the side of the house when i need to.

just been reading the link on your signature, starting to think i need to put a bit more thought into the base now as well

 

[MikeG.]

If the functions are separate, then two separate buildings each under the BR limit is a sensible idea. The smaller one can even be made of 2x2, not 3x2 framing. I've got a thread somewhere on another forum in which I build one. I'll see if I can find it later.

 

[jamie1976uk]

Thanks for the advise

In terms of the base. The area is currently paving stones. It's all nice and Level and solid. So I was thinking of just laying a timber frame on that. .. but going by your thread... I guess that's a big no no?

 

[MikeG.]

A huge no-no.

The nearest the lowest piece of timber should be to the ground is 150mm.

 

[jamie1976uk]

A huge no-no.

The nearest the lowest piece of timber should be to the ground is 150mm.

what about cementing some blocks onto the paving stones ? I suppose that would just put too much pressure on individual paving stones though... urgh really wanted to avoid having to dig foundations

 

[MikeG.]

You don't need to dig foundations. Well, put it this way, you need only to dig through the topsoil.......which in an urban garden might possibly only be 4 inches. Scrape down to something solid, fill with some crushed hardcore, or even ballast (sand & stones), then lay some pre-cast concrete lintels (every builder's merchant sells these in a multiplicity of sizes) down and bash them level with a rubber mallet. Build off that.

One day I'll update my shed thread with a drawing showing that detail.