Insulating workshop roof. Spray foam. Thughts?

[gaz1]

the car stuff for windows should last the longest from what ive seen with cars always stays black and seems to stay solid enough

it fastens between metal and glass and its solid enough to hold the glass on a car

and its also a good seal the bitumin tar on those types of roofs always fails we know that from garage roofs

 

[LiftedDisco]

If you are able to get above the leaking areas, and know of any bad seams or cracks that are letting the water in, I’d suggest using Acrypol which is widely available and is a fibreglass bonded waterproofing paint.

Don’t get it on you… otherwise the crematorium will be asking for COSHH sheets when they come to deal with your remains in years to come.

The upside is it will work on your roof…

 

[Roger440]

But you would be happy to slather it all in expanded foam, how are you going to see any leaks? if it does leak its just going to rot the encased steel, especially the fixings for the sheets
Rockwool doesn't absorb moisture

I probably wont. Well not until they are quite bad.

I accept that its not ideal. But equally i dont have an unlimited budget. I consider the over roof idea almost as bad. Again, how would you know you have a leak? You wont if the original roof doesnt leak in that place. You just have sopping wet rockwool.

The right way to do it is to strip it off and use composte panels. Will outlast me, looks good, especially inside. But way over budget.

 

[Roger440]

If you are able to get above the leaking areas, and know of any bad seams or cracks that are letting the water in, I’d suggest using Acrypol which is widely available and is a fibreglass bonded waterproofing paint.

Don’t get it on you… otherwise the crematorium will be asking for COSHH sheets when they come to deal with your remains in years to come.

The upside is it will work on your roof…

At the moment i minded to hire a genie lift or similar, get up there and seal the cracks. If i can do it whilst remaing in the basket, i will be happy with that.

i know where they are. 9 in total, all very small.

 

[gaz1]

no matter what you do any repair that you do will only be temporary on that style of roof

whilst i know what happens with tar on a slate tile roof or a stone roof any leaks after this its got no where to go

as goes for sealing asbestos roofs or cement fibre roofs it was a butyl patch for the screws nails to seal them of coarse they failed over time they always did do

there is this but its always at cost and will it last i couldnt tell you I certainly wouldnt advise it

 

[Gritineye]

On a system like that what's stops condensation/moisture from saturating the rock wool? or is there a air gap im not seeing?

Doesn't he existing roof sheeting becomes the vapour barrier? Then any water vapour moisture that does get to the underside of the new sheeting will be carried up the corrugations by air from the gutter end up to the ridge and vented out.

 

[gaz1]

Doesn't he existing roof sheeting becomes the vapour barrier? Then any water vapour moisture that does get to the underside of the new sheeting will be carried up the corrugations by air from the gutter end up to the ridge and vented out.

in theory any leaks would evaporate and exit via holes at the top of the apex

ive always known the apex points to be blocked so really theres no escape of any water with evapouration

the wood roofs use this method but metal roofs dont

 

[Roger440]

no matter what you do any repair that you do will only be temporary on that style of roof

whilst i know what happens with tar on a slate tile roof or a stone roof any leaks after this its got no where to go

as goes for sealing asbestos roofs or cement fibre roofs it was a butyl patch for the screws nails to seal them of coarse they failed over time they always did do

there is this but its always at cost and will it last i couldnt tell you I certainly wouldnt advise it

Depends how long temporary is.

Ct1 in the crack with some sand sprinkled on it whilst wet should last long enough for me.

If i have to do something like your vid, then im spending serious coin. In which case just do steel composite.

 

[Gritineye]

the wood roofs use this method but metal roofs dont

Of course they do, a plain ridge cap a vent at every corrugation.

 

[gaz1]

Of course they do, a plain ridge cap a vent at every corrugation.

the ridge cap has foam inserts to stop the water running under the cap

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then its supposed to have an over vent for escape

 

[Pond frog]

I know spray foam isn’t ideal but if it’s the only option that fits your budget then there’s probably not a lot to think about.
it doesn’t have a great reputation but a lot of that may be due to it being used in unsuitable situations and because mortgage companies hate it because it makes it very hard to inspect for potential problems

 

[Gritineye]

the ridge cap has foam inserts to stop the water running under the cap

then its supposed to have an over vent for escape

Jeez! It's just a shed, and it doesn't need eves fillers either, why do you always over complicate everything?

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[Roger440]

I know spray foam isn’t ideal but if it’s the only option that fits your budget then there’s probably not a lot to think about.
it doesn’t have a great reputation but a lot of that may be due to it being used in unsuitable situations and because mortgage companies hate it because it makes it very hard to inspect for potential problems

Yes, its frequently mis-used. Anything involving timber is likely to lead to problems.

In this application, its as close to an ideal scenario as you cant get. Other than a missing inner layer, its not really much different to a composite steel roof.

They did do a performance and condensation risk anaylisis. Which on the face of it, looks to have been done correctly.

 

[8ob]

I know a guy that does classic car storage in two big old farm buildings, they have had the roof and walls foam sprayed, it’s that well insulated that the dehumidifiers actually warm the place up. As far as the roof goes I think it would be better to replace the few big six sheets that are cracked, they are so cheap S/H it’s not worth the risk for the few quid saved.

Nice shed Roger

Bob