Roof tiles on a glorified shed - need foundations?

[Pallet Fancier]

I'm planning a workshop and collecting materials for it. A neighbour will be having a bedroom built on top of his integrated garage in a month or so and has offered me the roof tiles from the garage for my workshop.

I'm conflicted. I'm worried about the weight. Could be up to three tons sitting up there. I have the timber to do it, but am wondering if I will now need deep footings to support the walls, which would be a problem as it's heavy clay soil and there will be a lot of big tree roots, down there.

I also can't think of a shed/garden workshop I've seen that had such an extravagant roof! Other than cost, I wonder if the foundation/support problem is the reason.

Is it a problem or not?

Cheers

 

[Jameshow]

Foundation wise I think you will be fine ...

However you will need ties at ceiling height to stop the rafters splaying and a more hefty ridge timber esp if it's a shallow apex.

Also it needs boarding to prevent racking. A shed type construction will rack under the weight before long.

 

[Sheptonphil]

I also can't think of a shed/garden workshop I've seen that had such an extravagant roof! Other than cost, I wonder if the foundation/support problem is the reason.

Is it a problem or not?

Cheers

it’s not a problem per say, but your construction has to meet the load.

My workshop build was dictated by the planning condition that I had to use slate or fibre cement slate roof tiles. Even the fibre cement meant a 1800kg - 2000kg load, which dictated a heavier rafter structure, which dictated a heavier wall structure to hold the combined tile and timber roof, which dictated a better foundation. So use the tiles if you wish, but they could end up a poison chalice. See if you have to redesign just to use them and at what cost. Sometimes free just ain’t free.

 

[Pallet Fancier]

it’s not a problem per say, but your construction has to meet the load.

My workshop build was dictated by the planning condition that I had to use slate or fibre cement slate roof tiles. Even the fibre cement meant a 1800kg - 2000kg load, which dictated a heavier rafter structure, which dictated a heavier wall structure to hold the combined tile and timber roof, which dictated a better foundation. So use the tiles if you wish, but they could end up a poison chalice. See if you have to redesign just to use them and at what cost. Sometimes free just ain’t free.

Well, I'll be using a big stack of floor joists and rafters I got off a demolition site (free), and not one of the long ones is light enough that I can carry two at a time! I was musing in another thread about how to cut the rafters down into two studs, each (to make more efficient use), but it sounds like I shouldn't bother if I use the (free) tiles! Sounds like I'll need that mass in the building.

As a matter of interest, why did planning require you to use roof tiles? Was it to do with fire risk reduction?

 

[Sachakins]

Planning rules don't consider that aspect of a build, only its impact and cohesion into surroundings.
It's building regs that determine build requirements and safety.

Most shed roofs are quite shallow pitch, so normal roof tiles are not normally suitable, hence the use of felt, felt shingles, pressed pantile metal tile sheets or onduline corrugated roofing sheets etc.
The shallower the pitch, the greater the outward load on the walls, the steeper the pitch, the more the load is downwards on the wall to the foundations, this is why shallow pitch roofs have have lightweight roofing products.

 

[sirocosm]

I personally would prefer the tiles, they look nicer and last longer. But as mentioned, it means you may need a steeper pitch then most sheds have, and steeper pitch normally means a taller building. I think the steeper pitch with tiles will look much nicer, I am not so fond of buildings with shallow pitched roofs. May I ask how far you plan to build from your property boundary? I believe if you go over 2.5 meters height at the ridge, you need to get planning permission if you are within 2 meters from the boundary. If you are at least 2 meters away, then you can go to 4 meters high without planning permission in most places.

 

[Pallet Fancier]

Planning rules don't consider that aspect of a build, only its impact and cohesion into surroundings.
It's building regs that determine build requirements and safety.

Most shed roofs are quite shallow pitch, so normal roof tiles are not normally suitable, hence the use of felt, felt shingles, pressed pantile metal tile sheets or onduline corrugated roofing sheets etc.
The shallower the pitch, the greater the outward load on the walls, the steeper the pitch, the more the load is downwards on the wall to the foundations, this is why shallow pitch roofs have have lightweight roofing products.

This will be my first tiled roof building, assuming I go ahead with tiles, so thanks for the explanation!

 

[Pallet Fancier]

I personally would prefer the tiles, they look nicer and last longer. But as mentioned, it means you may need a steeper pitch then most sheds have, and steeper pitch normally means a taller building. I think the steeper pitch with tiles will look much nicer, I am not so fond of buildings with shallow pitched roofs. May I ask how far you plan to build from your property boundary? I believe if you go over 2.5 meters height at the ridge, you need to get planning permission if you are within 2 meters from the boundary. If you are at least 2 meters away, then you can go to 4 meters high without planning permission in most places.

I'll be within 2 metres, and was assuming I'd go to 3 metres high to get the necessary internal height. That, and I need to elevate the floor, and incorporate rat defences, thanks to a usually shallow waterway nearby that overtops its banks once every ten years.

No idea what the delay to getting a planning application might be just now, but currently regard it as a layer of buggeration and cost that I could do without. But can't really go 2 metres away from the fence, either! It's not like I'd be making an eyesore - the neighbours have two "erections" hard up against their side: one a rotting shed with a blue tarp roof, and the other a revolting plastic "wendy house" thing sold as a quick to build shed. So I'll be raising the tone, whatever I do!

 

[sirocosm]

I am relatively new to the UK, so maybe someone can confirm, but I think you are only allowed 2.5m total height if you are within 2m of the boundary. I am currently building a workshop and it is the same deal where I live, lots of older garages/sheds taller than 2.5m right against the boundary. I suppose they would have had to get planning permission for everything back then, but it was probably easier than now with permitted development. I also didn't want the hassle, so I wound up building my shop right in the middle of my yard, but to be fair I did not try to get permission to do it otherwise.

At 2.5m total height, it means the roof will have to be almost flat, which limits the choice of roofing materials.

 

[Spectric]

My large shed, 12 by 14 foot has a slate roof, with sarkin board underneath and the slates were heavy. Made roof trusses from 4 by 2's and a 6 by 1 ridge beam, shed structure is all 4 by 2's with nogins and clad in 6 by 1 boards. Believe roof pitch is 30° and building standard code BS 5534 states minimum is 20° although roofer said he 25° is better. As for footings, it sits on nine 500 mm square supports that are 3ft deep and it has stood without movement for the last nine years. Clay tiles may be heavier but you will not need the 18mm OSB sarkin boards I used.

 

[Sheptonphil]

Well, I'll be using a big stack of floor joists and rafters I got off a demolition site (free), and not one of the long ones is light enough that I can carry two at a time! I was musing in another thread about how to cut the rafters down into two studs, each (to make more efficient use), but it sounds like I shouldn't bother if I use the (free) tiles! Sounds like I'll need that mass in the building.

As a matter of interest, why did planning require you to use roof tiles? Was it to do with fire risk reduction?

Yes, planning stated it had to be sympathetic to the original buildings. This estate, being built on Duchy land, had all permitted development stripped. As my workshop was attached to the house and as big as many accommodation extensions, planning insisted it matched house roof covering. (which is slate). It was building control that then got involved with construction materials due to proximity to the boundary. ‘Predominantly non-combustible’.
have a peruse of my workshop build WIP on here.

 

[angelboy]

This is one of my outbuildings with red clay tiles. It’s been up 6+ years and there’s be no issues at all, it’s still solid - which surprises me considering the huge sycamore tree a metre away from the foundations.

https://www.ukworkshop.co.uk/threads/shed-build-wip.83913/

 

[okeydokey]

I'm planning a workshop and collecting materials for it. A neighbour will be having a bedroom built on top of his integrated garage in a month or so and has offered me the roof tiles from the garage for my workshop.

I'm conflicted. I'm worried about the weight. Could be up to three tons sitting up there. I have the timber to do it, but am wondering if I will now need deep footings to support the walls, which would be a problem as it's heavy clay soil and there will be a lot of big tree roots, down there.

I also can't think of a shed/garden workshop I've seen that had such an extravagant roof! Other than cost, I wonder if the foundation/support problem is the reason.

Is it a problem or not?

Cheers

Forget the roof - could the tiles be used to make a tile hung side that might help the structure merge into the environment?