Dreaded Spray Foam Insulation

Kindof

I am in the process of buying a cottage but have discovered through the building survey that there is spray form insulation in the loft roof. This is obviously a problem. Going forward if I wanted to resell or borrow against the property this is likely to prevent this happening. Lots of lenders don't accept properties with spray foam. I could not get access to the loft during viewing.

I really like the cottage and now have to go back and renegotiate price. I'm wondering if any builders or house owners out there have any experience of having this stuff removed. I understand it's a real headache. I  can't find any companies who specialize in its removal. I'd like to know how much it might cost to remove from the roof of a small two-bed end of terrace. What would need to be done? What parts of the roof would need to be replaced? What about disposal? What is the worst thing about spray foam on the inside of a roof?

The owner apparently has paperwork. My feeling is that the paperwork is irrelevant and makes no difference to lenders. Also, they say it was sprayed onto felt. Does this make any difference to removal?

Finally, why is this nasty stuff still being pushed on unwary home-owners?!!

Many thanks if you can help!

Slithery

Kindof said:

What parts of the roof would need to be replaced?

All of it.

scoot65

Kindof said:

I am in the process of buying a cottage but have discovered through the building survey that there is spray form insulation in the loft roof..............

The owner apparently has paperwork. My feeling is that the paperwork is irrelevant and makes no difference to lenders. Also, they say it was sprayed onto felt. Does this make any difference to removal?

Although I have no experience of the spray insulation, I would say that the fact that it's been sprayed onto the underlay  felt is a good thing. At least it's not on the back of the slates / tiles.   It would mean removing the slates / tiles off the roof, ripping off the underlay felt, replace with new underlay felt and refit the previously removed slates / tiles.

That's got to be much better than having the spay insulation stuck to the back of the slates ruining them.  Obviously the roof timbers would have to be cleaned and inspected.  

princeofpounds

I have no particular expertise in this area, but I find it remarkable that this stuff is employed in American homes all the time with few apparent problems and certainly no lending restrictions as far as I am aware, yet here it is anathema... Anyone know why?

oldbikebloke

princeofpounds said:

Anyone know why?

because the average person is too lazy to use google and research for themselves
it is not "verboten", it is simply a question of "appropriate choice"
https://www.which.co.uk/reviews/insulation/article/spray-foam-insulation-ajTlp7t5K7lT

as ever, the website you read about its "facts" should be considered against what are they trying to sell you...
https://www.1stassociated.co.uk/articles/spray-foam-insulation.asp

greatcrested

I don't see that price rengotiation is appropriate.

Either you are happy to accept the spray insulation, in which case proceed as agreed.

Or it is a show shopper for you in which case find a different property.

917700

This is a really big problem. The roof will be damaged due to the poor ventilation. The worst thing is the roof timber will be rotten and you need to replace the whole roof and roof structures. 

FreeBear

Kindof said:  What parts of the roof would need to be replaced? What about disposal? What is the worst thing about spray foam on the inside of a roof?

If you are real lucky that there is a layer of felt between the tiles and foam, the tiles could be reused. It may be possible to clean the roof trusses, but it is likely the battens will need to be replaced. The foam is not recyclable and can not be burnt, so will have to go in a landfill site.

PU foam gives of toxic gasses as it cures, and it is flammable - When it burns, yet more toxic fumes are given off, so a double whammy there. If the stuff encases timber, it prevents moisture from evaporating (don't believe the claims that open cell foam is breathable, it isn't). Damp in timber promotes rot and provides a nice breading ground for mold and fungus (wet or dry rot).

Why is this stuff sold to unsuspecting home owners ?

They are suckered in by glossy brochures, slick sales patter and promises of energy savings without any warnings of the dangers & risks. It is used quite a bit in North America, and it doesn't take too long to find countless horror stories of poor installation and nightmare repairs. One thing to bear in mind is many American houses are built almost entirely from timber and have a very short design life - If you are demolishing and rebuilding every 40-50 years, there is little incentive to take a long term view.

martindow

I would not be at all confident that it was sprayed onto felt and that the slates could be easily removed.  A more likely scenario is that the felt was rotting away and you could be see daylight between the slates.  Spraying with foam was then pushed as a cheaper alternative to replacing the roof properly.

TimHo

As recently as March this year (2021) I was offered a government grant to have the roof sprayed with polystyrene foam so I am wondering if there is not an element of exaggeration here ? Of course I do believe that anything this government does will be with only my best interests at heart!
While  I don’t know the answer to my own question I would ask,as someone with some experience in the building trade,”why would you want to do this?“It makes no sense to me to do it unless you want to cover up some defect in the roof that you don’t want a prospective buyer to see

AdrianC

TimHo said:

As recently as March this year (2021) I was offered a government grant to have the roof sprayed with polystyrene foam so I am wondering if there is not an element of exaggeration here ? Of course I do believe that anything this government does will be with only my best interests at heart!

I presume...
https://www.gov.uk/guidance/apply-for-the-green-homes-grant-scheme#what-the-voucher-can-be-used-for

There's nothing to say it CAN'T be used for PU roof foam, but that's certainly not the same as it being explicitly recommended. The foam is an insulator. It's just got big negatives in a lot of properties.

There are also subtleties of foam type - water should just run off closed-cell foam, whereas it'll soak into open-cell. There may be additional ventilation measures recommended, and they may or may not be installed...