Spray foam insulation.

[RGT]

Any long term applied results finding of the use in rooves and under slate applications?
Pros ;were easy spray applied,insulation, stick all slates/bond to rafters etc etc, cons, seals all up, timbers rot quicker,u valves on too good as expected?
Any veiws on the stuff?

[rogerm]

Birds will peck at it

[Badshot]

Rats and mice LOVE it to live in.

[Bumble]

As above; mice, birds squirrels etc love it, if you have to repair your roof it's a pain, it's frightening how flamable it is if you manage to set light to it.

[RGSP]

I have quite a lot of contact with architects and roofing contractors, and spraying foam to the underside of slated or tiled roofs seems to be the biggest single cause of major roof problems nowadays. In some circumstances it might work, but the risks are very serious, and personally I wouldn't even consider it. Spraying the back of corrugated iron in a steel framed shed is another matter, and the only cases I know of have worked very well.

[no land farmer]

Don't do it, you don't want to seal the roof space up to make an air tight void

[J B]

Any long term applied results finding of the use in rooves and under slate applications?
Pros ;were easy spray applied,insulation, stick all slates/bond to rafters etc etc, cons, seals all up, timbers rot quicker,u valves on too good as expected?
Any veiws on the stuff?

Are you talking domestic or agricultural?
We did some above the milking parlour about ten (?) years ago. Apart from a few vermin and bird holes, it looks fine.
I would guess that what folks above say about ventilation may be a problem in domestic situations, but I'm sure there are other ways of letting air in/out

[RGSP]

The reduced ventilation is no worse than what would happen if the roof was re-felted and re-slated, and can easily be coped with.

The real problem is that the roofing battens are encapsulated in a wet space between the slates and the foam, as are the slating nails. It's worse with old battens which are not preservative treated, but even new battens will not stand that for long, neither will the nails. Within a few years the whole roof covering is just sitting there more or less under its own weight, with no positive fixing. The foam holds it together well to start with, but it does deteriorate with time, and once the adhesion starts to go, and slates (or tiles) start coming off, there's not much alternative but to replace the whole roof, and the tiles or slates often aren't re-usable after foam either.

There may be examples where foam is working extremely well, but I do know of quite a number of cases where the above has happened.

[RGT]

So if a tight dry roof, with no felt underneath, and you want to use the space, best to kingspan, tri-layer foil, and plasterboard best option?

[rogerm]

TLX silver/Trioso would be easiest IMO

[RGT]

Is that multi layer fabric type you staple up
Rog?

[Gee]

Can creep out under pan tiles, then expand and crack the tiles........
gee

[rogerm]

Is that multi layer fabric type you staple up
Rog?

Yes that's the stuff, sometimes you also need a sheet/vapour barrier
Google web dynamics & the answer will be there !

[Ronnie66]

I have found some information that answers many objections about insulating with spray foam. It is not as straight forward as it seems, especially when insulating farm buildings.

https://www.homelogic.co.uk/icynene-insulation-dangers/

[Ronnie66]

The reduced ventilation is no worse than what would happen if the roof was re-felted and re-slated, and can easily be coped with.

The real problem is that the roofing battens are encapsulated in a wet space between the slates and the foam, as are the slating nails. It's worse with old battens which are not preservative treated, but even new battens will not stand that for long, neither will the nails. Within a few years the whole roof covering is just sitting there more or less under its own weight, with no positive fixing. The foam holds it together well to start with, but it does deteriorate with time, and once the adhesion starts to go, and slates (or tiles) start coming off, there's not much alternative but to replace the whole roof, and the tiles or slates often aren't re-usable after foam either.

There may be examples where foam is working extremely well, but I do know of quite a number of cases where the above has happened.

Those cases gone bad, would there be a possibility of a mistake from an installer or wrong type of foam used?

[Ronnie66]

Many contrasting experiences with expandable foam insulation.
I would never go with inexperienced installers who I know nothing about. I would search for some reviews also. The second thing would be the product itself. I guess to count out the risk of having a poor quality equivalent of foam sprayed in your property, it's best to speak to the contractor and get them to show you the certification and paperwork proving the use of original product.
That's my idea anyway to avoid disappointment and costly repairs.

Read for guide https://www.sprayfoamexperts.co.uk/s...ion-dangerous/

[Ironhead]

I bought a house with spray insulation in the roof covering timbers and slates. As people have said it is really not good I now know as water ingress can’t be detected. When I was selling the buyers survey picked it up as an issue and they pulled out. I spent £12k on reroofing tiles and batterns. The roofer didn’t follow modern building regs for ventilation just replacing as is. The next buyers survey picked this up plus further issues in a different part of the roof with poor ventilation. So had to figure out what ventilation was actually needed plus more re roofing. £20k later and about a 9months the house finally sold. Nightmare. Life lesson: never skip the survey when buying a house.

Never never put this stuff in your roof.

If if you have a spud cold store fair enough.

I don't know about the products that are available today, but a few decades ago (on this side of the pond) farmers who had spray foam inside their potato warehouses were being cautioned that if a fire started, to run as fast as they could because the chemicals in the burning foam was very toxic.