Spray-on foam roof insulation. Is it any good?

Thank you all for your replies which are unanimously against it. I've done further research and found a lot of negatives. There are firms that specialise in removing the foam, which says a lot.

I suspect that the expected life of such lightly built properties will be much shorter than in the UK, so if the houses do develop the same type of problems, they wll just be pulled down and rebuilt.

Houses.

The show I watch in the USA has very cold Winters, lots of snow and rain.The house on the programme are timber framed, literally planks of wood, then spray foam is applied then plasterboard over that.
The roof is also wood with felt and felt ‘tiles’ over. Nothing very different there, in fact even more likely to cause problems I would think , maybe the air con/ heating being on 24/7 makes the difference? And of course they have to have certificates for proof of spraying against Termites to sell their properties.

I wasn’t so much comparing the different methods of construction, merely asking if they are storing up problems for the future. If not then why?

It is not that that this kind of foam insulation causes damp and rot in every house, but that it causes damp and rot in sufficient houses for it to be a a known risk

Construction techniques and materials in the US are very different compared with the UK and the age profile likewise. In Britain we have millions of 19th century brick houses with slate roofs over timber joists and rafters. Weather conditions are also very different, we have a far wetter climate than most of the US.

On the other hand the US has a real problem with buildings being badly damaged by termites, not a problem common in the UK. It really isn't possible to compare the use of one material in two different countries, when everything else about the weather and construction details is so different.

It’s odd isn’t it, we don’t want to touch it here, but on the US house ‘fixer upper’ programmes on TV ( of which there are many) they spray the whole, wooden, house with it. Inside the walls, the roof, nowhere escapes.
I wonder if it’s different a different chemical mix? or if they were to go back in 10 years time we would see that the whole house is riddled with damp and rot?

Is it any good? Who knows but it raises so many problems it’s not worth touching with a barge pole!

No,no, no no, no and no again. It could make it impossible to sell your house, should you need to, as no lender will give mortgage on a house with this type of foam insulation, because of the dangers of damp and wood rot inherent in the product and because there is no way of checking for the presence of damp and wood rot without removing, or at least damaging the insulation.

It should be avoided at all costs from what I've read kathsue for the reasons Oopsadaisy and Redrobin have given.

A friend had this done and regretted it as it caused a damp problem.

As Oopsadaisy1 says do not do this. The BBC Programme Money Box (radio 4) had information recently about this, worth listening to:
www.bbc.co.uk/sounds/play/m001fm12

Don’t go near it

Many mortgage companies won’t lend on a house with this in the loft, not good when you want to sell.

It can also rot the wood in your roof, which is why it’s a definite No.