Spray foam insulation

anon_2020

I am in the middle of a chain of three and very keen to move out of my current accommodation (growing family, wanting outside space etc).

We have had an offer accepted despite apparently not having made the highest final bid (vendors wanted to sell to a family) and the property is one of the last non-expanded homes with a large plot on a desirable street. Ticks a lot of boxes for us and might take a while to find anything else as good.

If all goes to plan we will be moving in with a 75% LTV mortgage and £140k cash in the bank to carry out various improvements (full re-wire, possibly new central heating, new kitchen, knocking through some rooms etc). We want to build a wrap-around ground floor extension and convert the loft but these will probably have to wait until if/when have more money.

Surveyor has pointed out spray foam insulation in the loft and marked this as priority 2 (of 3) for attention, saying it should be removed 'at earliest opportunity'. Mortgage has been arranged so I'm not concerned about this affecting my financing. We would plan to be at the property for 20+ years so I'm not concerned about resale. Within that timeframe we would expect to carry out a loft conversion which would give us the opportunity to remove the foam insulation or even replace the roof entirely.

There is a lot of hysteria out there about spray foam insulation. Given everything outlined above, I'm inclined to have a roofer take look in the loft and give their best estimate of whether the roof is in decent shape, and how much it might cost to get the foam removed as a one-off job (ie before we think about converting the loft). I'm thinking this might be enough to give me confidence to proceed despite all of the 'RUN AWAY'-type comments that typically seem to be associated with this type of insulation.

Am I deluding myself?

propertyrental

Removing the foam will almost certainly involve removing the roof. Willned doing.

Assuming the mortgage lender is happy to lend (has done the Valuation, is not informed by their (ie your) solicitor) of the foam, and assuming it's not currently causing problems, do it when you convert the attic.

Main issue might be damp in the attic due to reduced/lack of ventilation. Any indication of
 fthis?

anon_2020

Seems nice and dry from the photos the surveyor has supplied but then it has been very warm and dry lately. This is something I can ask the roofer to pay attention to once I find one who's willing to have a look and express an opinion.

ThisIsWeird

My understanding of this is that provided the loft space very well ventilated, and the outer roof covering is sound and not letting in water, there should be little risk, at least in the medium term. So, if everything else ticks all the right boxes, and you are certain you are getting value for money, then I personally would be likely to go for it.

This would, tho', be on the basis of having the SI removed during the forthcoming loft conversion.

Is this loft still a loft? IE, ventilated via the eaves and soffits as it was originally?

(On that note, if it is, then why spray the underside of the roof anyway?! What purpose does it serve? It won't keep an unheated and ventilated loft 'warm'. So unless it's to bond down loose tiles/slates, what is its purpose? I never understood this.)

anon_2020

Outer roof covering is concrete tiles which appear sound. Surveyor thought there was probably felt above the rafters (although this is quite an assumption to make given the whole lot is obscured with foam!)

Foam has been installed between the timbers, so the bottom edges of the timbers are still visible for inspection. 

Loft is still a loft. There are no eaves - roof is more or less flush with gable ends. I'll ask the roofer to give an opinion on ventilation via sofits. Presumably this could be increased as a medium-term mitigation against damp problems by installing gable vents etc?

I can only assume the vendors were throwing everything at the roof in an attempt to limit heat loss - polystyrene tiles on upstairs ceilings, lagging in base of loft, and this damn foam insulation between the timbers.

youth_leader

Polystyrene tiles on ceilings? I'm very surprised the vendors have kept them up, the publicity regarding the fire risk with these is pronounced.  

Section62

ThisIsWeird said:

(On that note, if it is, then why spray the underside of the roof anyway?! What purpose does it serve? It won't keep an unheated and ventilated loft 'warm'. So unless it's to bond down loose tiles/slates, what is its purpose? I never understood this.)

More often than not it has been used to 'repair' a failing roof - e.g. slipped tiles/slates, rotten battens, crumbling felt etc.

You spray the magic stuff on, and then from inside the roof looks perfect.

This is primarily why spay foam has such a poor reputation now... not that the foam material itself is the major issue, just that its presence is a strong indicator of a problem lurking underneath, and that poor application can create more problems than it can ever solve (e.g. the ventilation issue)

The kicker is that to confirm whether or not the roof is failing means removing the foam first, which is a devil of a job to do without causing more damage.

If I were buying a property with spray foam and planned a full loft conversion then I'd factor in stripping the roof completely (as this may give a better result for the conversion) and (as a by product) wave goodbye to all the foam in a skip.

Section62

anon_2020 said:

Outer roof covering is concrete tiles which appear sound.

Are they original to the build, or added later?

anon_2020

Section62 said:

If I were buying a property with spray foam and planned a full loft conversion then I'd factor in stripping the roof completely (as this may give a better result for the conversion) and (as a by product) wave goodbye to all the foam in a skip.

This would be my plan too, but I have no idea when I'd be able to do it - possibly 10 years or more, so I'd need to be reasonably confident in the roof in the meantime!

anon_2020

Section62 said:

anon_2020 said:

Outer roof covering is concrete tiles which appear sound.

Are they original to the build, or added later?

Unsure. It's a 1930s semi and the adjoining property has the same tiles so I might assume they were original if concrete tiles were in widespread use in the 30s but apparently they didn't become really popular until after WWII.

FreeBear

anon_2020 said:

Section62 said:

anon_2020 said:

Outer roof covering is concrete tiles which appear sound.

Are they original to the build, or added later?

Unsure. It's a 1930s semi and the adjoining property has the same tiles so I might assume they were original if concrete tiles were in widespread use in the 30s but apparently they didn't become really popular until after WWII.

A 1930s build, I would expect clay tiles. If this house is ex-council, it may have had a new roof put on in the 1970s.