Spray Foam Roof Insulation - Good Or Bad?

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The old part of our roof is c1850 slate with a couple of very slight leaks & no felt. One of the chimneys needs re-flashing as this also leaks slightly I think. The new part of our roof above the extension is somewhere between 1970-1995 with artificial slates & felt - seems in good order.

I have just been quoted £5k to repair/prep (1.5 days) then spray their foam on whole roof (60sqm).

Is the spray on foam good or bad?

Is felt the better or even only way?
 
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Seems like a very expensive but quick way of making future roof maintenance very difficult.
 
Avoid foam like the plague, causes more problems than it solves.
 
no no no no no

water get into the timbers cannot evaporate because of the foam and can decay to a dangerous level and the first you know of it is the roof sags or collapses as there is physically no way of seeing the timber as the underneath is fully covered you cant see the top as the tiles are stuck on with the foam

ask them if theres a guarantee against rot caused by the foam stopping the timber breathing

and when it comes to having your roof repaired properly watch the price escalate if they bother to quote at all as the don't know what state the timbers in and the extra work involved in removing the tiles coverd in foam
 
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agree with noseall et al .......get a nice new flashing round the chimney ;)
 
Admittedly, you don't know what some of these people spray. However I did a lot of research before I had the foam applied, you only need read the BBA certificate to understand that the foam is breathable and therefore allows the wood to breath! They also repair any leaks to the roof, they replaced plenty of my tiles (slates are just as easy), and also did two lead valleys. They guarantee the whole roof for 25 years and, unlike some of their competitors, they don't go in and out of business. Just be careful who you use, as the spray is not cheap, but you get what you pay for, and I couldn't be happier!
 
Hi Benja,

Could you answer a few questions for me:
How long ago did you have your roof done?
Why did you have it done - problems, insulation, etc?
What made you choose spray over conventional felt or re-felt?

In searching for information I have found a few horror stories, but it is normal for any national company to have the odd issue (& people will always shout louder about problems than praises). I have understandably found quite a few people to have reservations & issues with the whole foam theory. I have also found quite a few reports of people who seem to be very happy with spray, but if it is not your field of expertese...........

Our next move is to get a few local roofers & the like round to quote & make their recommendations. We still have an open mind.
 
heeelllooo coolspark

when i read breathable i tend to think not fully waterproof
but of course i am no expert
just trying to qualify our [my]advice more closely to your situation ;)

ok i have read your first post again

your roof leaks !!!! breathable foam !!!! the water as i say enters the tiles soakes the timber now as i say above your timbers need to dry out to stop rot

now i dont believe a company will give an unconditional gaurentee on timbers they are going to cover for 2 reasons

timbers have a limited life if not treated and aired properly and how do they know or do they test the timber before to see if they are treated and for general good condition before instilatation

i in my humble opinion think you would spend your mony better by doing a propper job rather than a quick fix ;)

remember stone cladding and how much they said it enhance and improove property when in actual fact it devalued caused damp and ruined the surface at an exorbitant amount
 
Spray insulation IS a bad idea directly on the roofing backing...BUT.

Consider that the recommended loft joist insulation level is now 270mm...that is huge and won't allow you to board your loft.

So on a new build there is no harm in using this spray stuff between your joists and boarding over as normal. The only considerations being that have avoided spraying around lighting fixtures and water expansions tanks to allow unimpeded access/enable you to spot/mend leaks in the future.

Then use celotex on the actual roof which will mean you can spot water ingress easily and have a double helping of insulation.

Mark
 
spray foam very very bad did 2 rooves last year that had been sprayed instead of losing usual amount of breakage you would expect to lose on standard terrace 25-30% we lost 75% of slates please pleaseplease get a reroof and why were we reroofing a sprayed roof i hear you ask IT WAS LEAKING
 
We got 4 recommended roofers round in 2006/7 to quote, decided to go for a complete re-felt & slate with one & booked for Feb 2007. He didn't show & we then spent the money. Now having it re-felted & slated in March 2010, I know this guy & he won't let us down.
 
*spam removed*
Well glad you took the time to read the original post.. and not suggest a product completely opposite to asked.. well done! :rolleyes:

Spray foam insulation internally to roofs is a quick fix and wont remove the problem, kinda like painting over cracks and putting a pot plant in front and hopeing the wife wont see it..

Well for domestic stuff its bad..
 

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