Replacing a “tin” roof, any pointers?

[alastairgott]

Does anyone know anything about metal shed/garage roofs. Just been asked about what quality we want and to be fair I haven’t a clue.


I think the red rose (bull pot) hut has a metal roof, so just interested if there’s anything I can glean in terms of budget (and cold) vs expensive (and quality warmth).


And if anyone knows where the good middle ground is.

[PeteHall]

The main issue with a tin roof is condensation I think. This will be a particular issue if you are drying wet caving gear in there.

A plywood deck below the tin might solve this inexpensively. But you would probably want to consider the ventilation between layers. If I recall, I believe the technique is to run battons up the ply, then counter-batton across, then fix the tin cladding to these.

For a shed, I can't see any point in a warm roof, but I guess that depends what you are using it for. If it's your workshop where you will spend 8 hours a day, it's probably worth it.

Personally, I'd be using something cheap like galvanised corrugated iron, but it doesn't look great. Depending where you are, you might also need planning permission, which would require specifying the materials. In a conservation area you might be forced to use something expensive...

Edit: should probably point out that I'm not an architect and I know sod all about ventilation and insulation, but I've seen a  fair few details as a structural engineer...

[RobinGriffiths]

Great disclaimer there Pete, but makes a lot of sense.

[Down and beyond]

If it’s a small shed and you no any local farmers they normally have lots of off cuts due to all the grain stores now days are built in this for roofs also their stuff is the highest quality

[Pete K]

It's a double garage sized space and we're trying to figure out how thick the bonded insulation foam needs to be on the roof panels (and then if we can afford it!).

[Down and beyond]

So under the sheets you want 80mm - 100mm to insulate it depends on what the garage is going to be used for really ?

[Pete K]

Storage, changing, hanging kit up to drip dry without freezing solid in winter. It won't be an 'occupied' space, more like a utility area and workshop. It won't need insulating to the same standard as a normal internal house or workplace space, but some insulation would improve it and the roof needs doing anyway. We're just not sure how much insulation is needed really.

[Down and beyond]

I would go around the 50mm mark then that way your safe either way , you could still go a bit less to be honest 40mm would still work and do it’s purpose  and it’s cheaper you should search the internet for offers of buying +5 sheets unless you have a builders merchants account or no somebody with one they normally get 30% of

[Down and beyond]

Other option is a linear sheet with a z bar in between them so in theory you have to roofs this stops condensation  and doesn’t need insulation, I would make sure your  ends and sealed up well with fix all for example and your screws are decent , it’s common the seals around the screws leak when cheap and after all the money / effort you don’t want a leak 

[LJR]

During the last lockdown I built myself another shed. It is a concrete sectional one with a single pitch roof. I put plywood sheets down first then 30mm of Kingspan sheets, then box profile cladding sheets. It has upvc windows and door. Unfortunately, I think I made too good a job of sealing it all up and I am now getting mould on the plywood inside. I think the lesson here is that you must have some airflow inside to get rid of moisture. When the weather improves, I will have to cut some vent holes to try and get round this problem...

Les

[PeteHall]

I think the lesson here is that you must have some airflow inside to get rid of moisture.

Agreed. Ventilation is very important.

[Down and beyond]

Definitely need the ventilation especially for the purpose of having wet clothes in their to dry , a good idea is to bang a fire place inside of it or a log burner even and leave the door wide open that way you have the Benefit of it in the winter  windows are good if you can leave open but depends if you have the issue of theft . Much to think about

[pwhole]

There's no shortage of ventilation - that definitely isn't a problem

[SamT]

Why on earth bother with insulatiin if the space is not heated and any heat will be lost via draghts anyhow.

[pwhole]

For the age-old reason that it's hot in summer and freezing in winter, and if we have ten hot bodies in there getting changed after a Peak trip in winter (oh, those heady days), the place will warm up quite quickly, instead of those poor kids going blue and shaking uncontrollably. The walls are a foot thick, and the draughts aren't so huge. The heating's usually on in the main room too. Simply, we're building a sweat-lodge

[Speleofish]

Sounds like you need ventilation (to get rid of all the hot, sweaty, malodorous air) rather than insulation (to keep all that stinky air nice and warm and humid).

[owd git]

have you considered bonded insulated steel sheet via reclaimed  suppliers? have used same myself up to 5M. lengths. will post last supplier i used when i find records. they delivered too. farm recaims leek way if i remember correctly.    Ric'.

[sinker]

Sounds like you need ventilation (to get rid of all the hot, sweaty, malodorous air) rather than insulation (to keep all that stinky air nice and warm and humid).

You need both; insulation and airflow.

Post up a sketch and I'll draw you up a cheap fix with some easy details. 

[Chocolate fireguard]

I think SamT is right.
Unless you are going to do something like putting insulation on the walls (I imagine you are not) and replacing that sliding door (with a wall and a decent door) then you won’t be wanting to heat the space, and without that there is little point in insulating the roof.
I would have thought a reflective (white?) outer layer with 40 or 50mm insulation, as suggested by Down and beyond, would be about right.
That way you would at least have options in the future if you wanted to improve the performance of the rest of the structure and put in some heating.

[Pete K]

50mm of bonded insulation was what I was thinking about. The garage doors are on the list for replacement with a modern sealed frontage too, so that deals with the big draft. We'll of course get vents for damp air. I'd love to insulate and clad the walls, but that is a discussion that needs to be had in future. Money prevents the lot being done in one hit, but starting with the correct materials on the roof will set us up for a warmer building further down the line.

[sinker]

I think SamT is right.
Unless you are going to do something like putting insulation on the walls (I imagine you are not) and replacing that sliding door (with a wall and a decent door) then you won’t be wanting to heat the space, and without that there is little point in insulating the roof.
I would have thought a reflective (white?) outer layer with 40 or 50mm insulation, as suggested by Down and beyond, would be about right.

Wrong wrong wrong wrong wrong.

Minimum 75 mm close cell insulated roof cladding panels (or 100mm if you can get them) with some trickle vents in a vented rigde will make a world of difference. You would be shocked how much.
Insulate the floor if you can or at the least run some pallets out on the floor and deck over them so that you have a cold well. Hang a heavy curtain over the door and stick a 100w tube heater in there as background heat and you'd be amazed.
I have a barn set up like this but worse, with hit and miss open boarding on the leeward side and I can sleep in there all year round in a summer sleeping bag.

How do we post photos up on here? I'll put up some examples.

Where do you live? Go round to any structural steel or cladding contractors and start buying up all the offcut or damaged Kingspan panels you can find. Agri contractors putting up farm sheds. Offer to empty their waste skips. You'll soon have enough. You'll also find all the flashings, foam tape and half used tubes of sealant you could ever need. They are literally giving it away.

[pwhole]

Personally I'm fed up with second-hand stuff, and would rather buy brand-new panels and do it right. We're always in this situation trying to save money pointlessly and we can afford it. And I agree, it would make a lot of difference if done properly. My landlord put a new slate roof on our building last year - I live on the top floor, so this room and my bedroom have a sloping roof with no airspace above, unlike my living-room, which has a loft above. Until last winter it's always been pretty cold in my bedroom and in here, but as they took all the slates off they were able to fit insulation panels before they put new ones on. This winter I haven't even put my thick quilt on and hardly have the heating on - I'm sat in a t-shirt now, and I can tell how much difference it would make in there.

[PeteHall]

How do we post photos up on here? I'll put up some examples.

https://ukcaving.com/board/index.php?topic=19799.0

[sinker]

How do we post photos up on here? I'll put up some examples.

https://ukcaving.com/board/index.php?topic=19799.0

Testing photo insert....

Here's 2 tin sheds I have on offer at the moment.

The one in the foreground I could do for around £800.
The bigger one in the background I could let you have for around £2.5M.

Any takers?

[pwhole]

The problem. it's about 6m X 5m in plan with a central spine about 1.5m higher. Don't discuss the timbers! A-frame at each end and one (almost) in the middle with longitudinal beams across the span. Incidentally, it's a lot tidier and cleaner since these photos were taken

[SamT]

Pete/phil.. I work i. the industry and we can have this chat offline.  CBA typing long stuff on my phone. I'll mail you tomorrow but got a funeral to go to so quite a busy day for me already.

[PeteHall]

Worth bearing in mind that Castleton is in a conservation area, so you may need planning permission to re-clad the roof.
https://www.peakdistrict.gov.uk/looking-after/living-and-working/your-community/conservation-areas

It would certainly be worth investigating this before buying any materials as planning officers can be hard work, particularly if you get off to a bad start...

The best approach is probably to speak to the conservation officer who covers the area and get their view on what sort of thing might be acceptable. Technically, they will want to charge you for a pre-app consultation for this, but you might find that they are just pleased you want to talk to them and have an off-record discussion for free. Once you know the sort of thing they will accept, choose your preferred product and provide a sample with the planning app and hopefully they will accept it.

I doubt that they will be interested in the construction details (unless it's listed), it will be the appearance that they care about, but you might still be able to blag anything as an improvement 

[pwhole]

Pete - don't worry, we've done all that - but thanks

[Chocolate fireguard]

I think SamT is right.
Unless you are going to do something like putting insulation on the walls (I imagine you are not) and replacing that sliding door (with a wall and a decent door) then you won’t be wanting to heat the space, and without that there is little point in insulating the roof.
I would have thought a reflective (white?) outer layer with 40 or 50mm insulation, as suggested by Down and beyond, would be about right.

Wrong wrong wrong wrong wrong.

Now come on, if you think I made a mistake tell me straight.
I might be sad for a while, but I'll get over it!