Foam loft insulation

sam1970

We are having a loft conversion going on and our builder used foam spray to insulate under the roof tiles. Do people think this is good enough to stop leaks? any risk of dampness? I am sorry but I am not very knowledgeble about these things so not sure if I need to provide more information

Davesnave

It's not usual to use spray foam to insulate under tiles. The only time it's normally done is on old roofs, to stop tiles slipping when maintenance becomes onerous, but it's a short-sighted measure, because it makes replacing the roof an absolute beggar.

The usual way to stop leaks is to have a roof with good integrity in the first place, and the usual way to insulate in a loft conversion is to use Celotex or similar board of suitable thickness.

Your builder sounds like a cowboy. Is the local building inspector involved in signing this off?

dggar

My niece's father in law had the sale of his house fall through because he had foam insulation sprayed in his loft. He had to get it removed to make it saleable.

missile

I would be concerned that moisture would be trapped between the roof tiles and foam and cause the roof timbers to rot.

the_lunatic_is_in_my_head

Someone had done this to the house we purchased, when the roof was renewed the slate tiles couldn't be reused as it was the original roof without a membrane plus the top third of the roof was completely rotten as the timbers couldn't breathe and roof had been leaking.

I agree with Dave that it's usually done to prevent tiles slipping and prolong a roof that's getting to the end of it's life but looking on Google there appears to be a lot of companies offering it. Personally I wouldn't be happy with it.

dancing_star

sam1970 wrote: »

We are having a loft conversion going on and our builder used foam spray to insulate under the roof tiles. Do people think this is good enough to stop leaks? any risk of dampness? I am sorry but I am not very knowledgeble about these things so not sure if I need to provide more information

I passed on buying a house with this spray foam insulation. There was no way of knowing how the roof timbers were.

Shame, it was a lovely house otherwise. Previous buyers pulled out for same reason.

You've made a bad mistake, imo.

Owain_Moneysaver

Did you specify spray foam insulation? The means of insulation and the U value calculations should be on the drawings submitted to Building Control, which your builder should be working from.

Unless it's specified your builder should not have used it, and should be told from the outset to remove it all and make good at his cost with compensation to you for the costs, delays and inconvenience caused. This may involve new roof trusses so is likely to give rise to a contract claim dispute.

Perhaps your home insurance has legal expenses cover (and you did tell them you were having a loft conversion?)

Furts

Owain_Moneysaver wrote: »

Did you specify spray foam insulation? The means of insulation and the U value calculations should be on the drawings submitted to Building Control, which your builder should be working from.

Unless it's specified your builder should not have used it, and should be told from the outset to remove it all and make good at his cost with compensation to you for the costs, delays and inconvenience caused. This may involve new roof trusses so is likely to give rise to a contract claim dispute.

I would not specify, or use spray foam. I too think OP has a serious issue here. It raises a couple of points. First did OP authorise this, or specify this, because the existing roof tiles and covering were dodgy? Second, was a Full Plans Building Regs Application made? If so, I fail to see how these were signed off with this material being used. However, if OP was on a Building Notice then an explanation exists here - basically the folly of adopting this approach is something OP has to take on the chin.

Ultimately if the foam has been applied strictly in accordance with the BBA Certificate, and probably by an approved BBA contractor, (or similar) OP may be in with a fighting chance. What did OP specify here?

Also what conversations have taken place with the Building Inspector?

sam1970

Thank you guys for the reply. The work has not finished yet and the loft is not boarded yet. Unfortunately I am not very clued about these things so please excuse my terminology. We never discussed the insulation type before work as the builder said he knows what he is doing and have used this stuff before. The building control officer, who is a private one, not council, made a visit recently and was happy with the work although I dont know the details. The house is very old so the roof tiles have nothing underneath them to insulate. I had a discussion with few builders before work start and all agreed that removing the roof tiles to apply insulation, whatever you call it, will be prohibitingly expensive job. The roof tiles are in a very good condition so we are hoping there should be no water leak.

the_lunatic_is_in_my_head

sam1970 wrote: »

I had a discussion with few builders before work start and all agreed that removing the roof tiles to apply insulation, whatever you call it, will be prohibitingly expensive job.

My understanding is, usually an insulation board (Celotex, Kingspan, etc) is wedged between the rafters (the timbers going from the wall up to the top of the roof) leaving a 1 inch gap between the tiles and insulation for air flow and if more insulation is required I presume an insulation backed plasterboard is used.

The only reason I can see for taking off tiles is if the room below the loft has the ceiling above the bottom of the roof leaving you with the option of removing the ceiling or the roof to get to the space inbetween on that bit that isn't in the loft.

In that scenario spraying a bit of foam in that small bit wouldn't be the end of the world (if building control insisted, I'd rather it was left empty) but that wouldn't give excuse to spray the whole roof.

In our case the house was pretty much empty, unheated and very damp plus the roof in poor condition with a lot of water coming in, I'm sure the foam quickened the deterioration of the timbers but it wasn't the sole cause.

At a quick glance the sites I looked at yesterday selling the spray foam application appeared to offer a 10 year guarantee for domestic installations, problem with that is I'd expect a decent roof to last a lot longer than 10 years.

Furts

sam1970 wrote: »

We never discussed the insulation type before work as the builder said he knows what he is doing and have used this stuff before. The building control officer, who is a private one, not council, made a visit recently and was happy with the work although I dont know the details.

The roof tiles are in a very good condition so we are hoping there should be no water leak.

Worrying. You are the client but you never discussed the roof insulation - a fundamental with loft conversions. Also worrying is the situation with the Inspector. I have previously suggested you should not be using an AI, but here one visits to represent your interests, for which you are paying, and they are answerable to you, yet you have no idea what was said.

You need to get hold of the AI, and get a firm, recorded response on the sprayed roof insulation. You need to highlight depth of coating, ventilation of the tile battens, BBA certification, Approved Installers and so on and put the AI on the spot. Then say you have no qualms about engaging, and paying, the local authority inspector to come along for a second opinion. That will put the AI on notice to perform.