Shed build, many many questions...

[Spectric]

I didn’t - haven’t heard of that before - sounds like a sticky job!

Yes it is a job that once done you just bin the brushes and the gloves as it is not worth trying to clean them. The bitumen basically turns ply into a waterproof material, two coats and forget. The ply on my shed sat in a recess on the wooden frame so I bitumed the bottom side of the ply and the edges, then sat it into my frame which was also fully bitumed and then painted the top face and filled the edge void so no chance of water ingress. I just used lino as the floor covering. It is the edges of ply that must not get wet because that starts the ply delaminating.

 

[Torx]

Roof pitch, I'm lost.

Based on the adjacent garage I've used 2.5°. Internet calculators (I'm not clever) say this is 0.52:12 or 1:23?

Roof covering...probably torch on felt.

 

[Molynoox]

Torx, looking really good! Exciting stuff isn't it.
4x2 isn't overkill, it's quite a big building, and 4x2 on 400 centres is fairly standard... It's certainly the most common config for garden room structures.
Sips are stronger than you think, also they get more expensive the more customised they need to be, windows etc
If you can buy the standard size panels and stitch them together yourself without the need for a design service and a custom cutting service then cost is probably similar to traditional framing.

On roof pitch, the standard is 1 in 40, or it might be easier to think of it as 25mm drop for every metre of building depth.
Example, if you have a 3 metre deep building it will be 75mm taller at the front than the back. 4m deep building would be 100mm. 3.5m would be somewhere in between, 87.5mm. not sure if that helps

Martin

 

[Molynoox]

Agreed metal sheet would be best esp if insulated.

Otherwise I was thinking a cut roof on top of sips dosent make sense.

I think they would be fine for a roof.

I'd be more concerned with a floor as the foam could possibly compress under weight of a operator and machine tool??

From a functionality perspective the metal roofing sheets are hard to beat, very strong, insulative, quick to put up and waterproof your building in a day etc. But I just don't like the look of them I don't know if that's a very valid perspective but it's where I am. Not that EPDM looks amazing, but I prefer it.
Martin

 

[Torx]

Torx, looking really good! Exciting stuff isn't it.
4x2 isn't overkill, it's quite a big building, and 4x2 on 400 centres is fairly standard... It's certainly the most common config for garden room structures.
Sips are stronger than you think, also they get more expensive the more customised they need to be, windows etc
If you can buy the standard size panels and stitch them together yourself without the need for a design service and a custom cutting service then cost is probably similar to traditional framing.

On roof pitch, the standard is 1 in 40, or it might be easier to think of it as 25mm drop for every metre of building depth.
Example, if you have a 3 metre deep building it will be 75mm taller at the front than the back. 4m deep building would be 100mm. 3.5m would be somewhere in between, 87.5mm. not sure if that helps

Martin

Thanks, that does help! Although different roofing materials (even different manufacturers it seems) call for quite different figures.

Still thinking about the roof construction / materials but it’ll likely end up being pretty basic as I just need to have somewhere watertight for winter storage at the moment, I’ve probably already blown the budget insulating the floor, but I can do the rest at a later date.

 

[Spectric]

From a functionality perspective the metal roofing sheets are hard to beat

But make sure you have good insulation underneath otherwise the warm air in the workshop will condense on the cold metal and you will have rain.

As for the slope, think of that as a storage area underneath so 25 to 30° and look at 41/1000 Tile Form 0.6 Thick Mica Coated Roof Sheet

or look at these Eternit Fibre Cement Sheets | Roofing Superstore® which are another option.

I wanted my shed to blend in and not look industrial so as I have an apex roof and sarking boards I had it tiled with slates.

 

[Molynoox]

But make sure you have good insulation underneath otherwise the warm air in the workshop will condense on the cold metal and you will have rain.

As for the slope, think of that as a storage area underneath so 25 to 30° and look at 41/1000 Tile Form 0.6 Thick Mica Coated Roof Sheet

or look at these Eternit Fibre Cement Sheets | Roofing Superstore® which are another option.

I wanted my shed to blend in and not look industrial so as I have an apex roof and sarking boards I had it tiled with slates.

Sorry, I was talking about the insulated Kingspan type metal/ PIR roof panels, not the metal sheets which, as you say, are a condensates dream

 

[isaac3d]

Stud layout...2 x 4s again - overkill? Probably.

View attachment 141140

Probably not overkill. Better to be safe than sorry anyway, especially if you hang heavy duty shelving for storing a lot of timber.

 

[Torx]

Probably not overkill. Better to be safe than sorry anyway, especially if you hang heavy duty shelving for storing a lot of timber.

Are 2 x 4 ok for the roof too?

 

[Molynoox]

Are 2 x 4 ok for the roof too?

If your span is 2.5m you will need 5x2 but I think you will be ok at 600 centres rather than 400
You can check the span tables online
Martin

 

[Spectric]

If your span is 2.5m you will need 5x2 but I think you will be ok at 600 centres rather than 400
You can check the span tables online

But that will depend on the roof covering, there is a lot of weight difference between slate, concrete tiles and profiled metal sheeting.

 

[Molynoox]

But that will depend on the roof covering, there is a lot of weight difference between slate, concrete tiles and profiled metal sheeting.

True

 

[Torx]

If your span is 2.5m you will need 5x2 but I think you will be ok at 600 centres rather than 400
You can check the span tables online
Martin

Ah, good point. Although I found myself pondering the storage available for an apex roof last night so things might change again yet…

 

[Torx]

I'm leaning towards an apex roof now. What do you vote for?

It feels a bit narrow but I do like the idea of somewhere to chuck long pieces of material. No idea how to build an apex roof though, so more research needed when I'd rather be actually doing stuff. Although if I leave it long enough maybe I'll be able to step outdoors without my eyeballs sweating.

 

[Molynoox]

Is there a height difference?
Seems to be, and if that is the case why not build the flat roof version at the pent roof height and get even more storage space....

I like the look of the apex version though, a bit different from the norm.

Martin

 

[Torx]

Is there a height difference?
Seems to be, and if that is the case why not build the flat roof version at the pent roof height and get even more storage space....

I like the look of the apex version though, a bit different from the norm.

Martin

From what I can gather you get 2.5m to the eaves with either design, but the max height can be up to 4m, the apex is 3.3m

 

[Molynoox]

Are you within 2m of the boundary? If so then you are limited to 2.5m height with either design.

 

[Torx]

Are you within 2m of the boundary? If so then you are limited to 2.5m height with either design.

Rats, you’re right, I don’t know how I missed that. Ah well, pent it is, and lower again as I’d had the eaves at 2.5m. Or planning I suppose, another setback.

 

[Molynoox]

At least we spotted it now rather than later

 

[Jameshow]

How about shallow trussed roof with space for storage?

Build some trusses 4" deep at each end 20" deep in the middle.

Gives you the shallow apex and storage on top of a 2m high wall.

To be really clever put a hatch in the eves for easy access.....