Leaking roof - Renotherm roof repair - opinions please.
Discussion
http://www.renotherm.co.uk/index.html
A friend has a 1950's fairly large detached house, and has started getting leaks through the roof due to rotting felt.
He's thinking of having it sprayed with what looks like expanding foam, by the firm above.
Any opinions from people that have used this, and opinions from roofers/builders would be appreciated please. He hasn't had a quote yet, but I would imagine it's fairly expensive, and have concerns about condensation, how long it lasts, and what happens should you need to re-roof traditionally (i.e. re-felt and batton) in years to come.
A friend has a 1950's fairly large detached house, and has started getting leaks through the roof due to rotting felt.
He's thinking of having it sprayed with what looks like expanding foam, by the firm above.
Any opinions from people that have used this, and opinions from roofers/builders would be appreciated please. He hasn't had a quote yet, but I would imagine it's fairly expensive, and have concerns about condensation, how long it lasts, and what happens should you need to re-roof traditionally (i.e. re-felt and batton) in years to come.
weeowen said:
some good reading especially as I was interested in cavity wall insulation and painting the wallsThe felt is a secondary barrier. The water shouldn't be getting that far.
Most roofs have a life minimum expectancy of 60 years, but most last many years beyond without much more than basic maintenance.
If there are numerous leaks, I'd be looking at getting a complete re-roof done, and take the opportunity to include an insulation upgrade at the same time. It would also give you the chance to check the state of the timbers if there has been water ingress, as some may need replacement.
Groucho, who posts on here, is a roofer.
I wouldn't go with the system shown, sealing the roof space can cause more problems than it solves.
Most roofs have a life minimum expectancy of 60 years, but most last many years beyond without much more than basic maintenance.
If there are numerous leaks, I'd be looking at getting a complete re-roof done, and take the opportunity to include an insulation upgrade at the same time. It would also give you the chance to check the state of the timbers if there has been water ingress, as some may need replacement.
Groucho, who posts on here, is a roofer.
I wouldn't go with the system shown, sealing the roof space can cause more problems than it solves.
I agree with the above.
If you have a completely dry, ventilated tiled roof construction, then it might make sense to spray insulation on the underside to give yourself a warm attic, though if there are problems later they are going to be hidden.
If your roof is leaking, you need to fix it I am afraid. If you spray this stuff on the underside it may appear to cure the problem for a while, but the water will still be getting in, and because the, probably timber, structure is sealed, it will hold the damp and very likely rot. The water will then come out somewhere even more unexpected and you will have some really serious problems.
If you have a completely dry, ventilated tiled roof construction, then it might make sense to spray insulation on the underside to give yourself a warm attic, though if there are problems later they are going to be hidden.
If your roof is leaking, you need to fix it I am afraid. If you spray this stuff on the underside it may appear to cure the problem for a while, but the water will still be getting in, and because the, probably timber, structure is sealed, it will hold the damp and very likely rot. The water will then come out somewhere even more unexpected and you will have some really serious problems.
I wouldnt let that " stuff " near a roof of mine . Add that to your roof and basically make the property un-saleable
As the guys have already mentioned if the water is coming through the felt , then the roof covering , ie the tiles or slates , have failed .
Anything less than a re roof will be a bodge imho .
As the guys have already mentioned if the water is coming through the felt , then the roof covering , ie the tiles or slates , have failed .
Anything less than a re roof will be a bodge imho .
Do not touch these spray on roof solutions with a bargepole! If the roof is generally leaking over it's entire surface, there is a general problem with the outer surface material and it is likely that the same will require to be replaced. At the same time you should also look at the condition of any supporting timbers etc. and replace or upgrade these elements as necessary.
Do not take any shortcuts with your roof, as any compromises here will come back to bite you in the wallet tenfold!
Do not take any shortcuts with your roof, as any compromises here will come back to bite you in the wallet tenfold!
deeps said:
http://www.renotherm.co.uk/index.html
A friend has a 1950's fairly large detached house, and has started getting leaks through the roof due to rotting felt.
He's thinking of having it sprayed with what looks like expanding foam, by the firm above.
Any opinions from people that have used this, and opinions from roofers/builders would be appreciated please. He hasn't had a quote yet, but I would imagine it's fairly expensive, and have concerns about condensation, how long it lasts, and what happens should you need to re-roof traditionally (i.e. re-felt and batton) in years to come.
If you have water leaking in it means your tiles are not doing their job, plus the felt is leaking as well. Which means you have water leaking under your tiles, and sitting there. I'd be very very wary of such a bodge up as spray on waterproofing inside the loft. A friend has a 1950's fairly large detached house, and has started getting leaks through the roof due to rotting felt.
He's thinking of having it sprayed with what looks like expanding foam, by the firm above.
Any opinions from people that have used this, and opinions from roofers/builders would be appreciated please. He hasn't had a quote yet, but I would imagine it's fairly expensive, and have concerns about condensation, how long it lasts, and what happens should you need to re-roof traditionally (i.e. re-felt and batton) in years to come.
Renotherm said:
Any lost or damaged areas will also be fully repaired by our qualified technicians prior to application of Renotherm
That probably means they will want to repair your roof before they start work anyway.It wouldn't be a massive job to have the tiles pulled and new felt put down, do it properly.
The Renotherm stuff is purely insulation.
As has been said. Don't go there.
Sounds like a re-roof is what is required.
Not as drastic or expensive an option as you may think.
I'm in Staffs and have had 2 re-roofs in as many years. 2 bed terrace £2k, 3 bed bungalow £5.5k
New lathes, new felt, new tiles. The job only will only need to be done once in your lifetime.
Sounds like a re-roof is what is required.
Not as drastic or expensive an option as you may think.
I'm in Staffs and have had 2 re-roofs in as many years. 2 bed terrace £2k, 3 bed bungalow £5.5k
New lathes, new felt, new tiles. The job only will only need to be done once in your lifetime.
B17NNS said:
I'm in Staffs and have had 2 re-roofs in as many years.
The job only will only need to be done once in your lifetime.
Are you on your second life? The job only will only need to be done once in your lifetime.
sorry, I know what you meant really IMO price varies alot depending not only on quality of workmanship and materials, but the design of the roof. If it has several valleys, hips or dormers that can add a fair bit to the price.
His is just a simple straight forward run though, but a large area (equiv to about 3 terraced) and needs to be scaffolded front and back.
Groucho, can I ask what make of felt you would recommend, bearing in mind that he may be converting the loft into living space in a couple of years, so celotex will be cut between the rafters.
Edited by deeps on Tuesday 9th December 20:10
roofer said:
Please don't use that, it will rot the frame in 2 years. If its leaking get a proper roofer to investigate, they do exist. 
Hi roofer. I'd be interested to know what you base that comment on?I've been involved with many loft conversions and have always used celotex, cut between the rafters and leaving an air void between it and the felt.
It's used extensively on new builds too, where the town house design means the roof space is living space. I know in such houses Taylor Wimpey use 3" thick celotex (bloody expensive)cut between rafters, then overlaid with 1" celotex across the face of the rafters, before plaster boarding.
Maybe you're thinking of something else?
Edited by deeps on Tuesday 9th December 21:07
I put my own tiled roof on the garage I built. I did a bunch of research, and even asked on here how the hell I get 720 concrete roof tiles onto the roof. Turns out you simply carry them up a ladder, a six pack at a time. I carried them up and laid the lot in little more than a day.
Real roofers could probably strip, re-felt and re-tile your house roof in a few days. I guess they would do it an area at a time, to save leaving the whole lot open to the elements.
Battens going over the felt:
Tiles going over the battens:
Real roofers could probably strip, re-felt and re-tile your house roof in a few days. I guess they would do it an area at a time, to save leaving the whole lot open to the elements.
Battens going over the felt:
Tiles going over the battens:
Good work KH no comment on the block laying though! only joking, at least it's plumb.
Btw, it's not my roof, I started the thread to dissuade my mate from using the horrible spray foam stuff, but didn't want to sound biased against it as to influence replies.
Using a ladder is ok for single storey work, but on a house scaffolding is sensible and a whole lot safer, easier and quicker.
Btw, it's not my roof, I started the thread to dissuade my mate from using the horrible spray foam stuff, but didn't want to sound biased against it as to influence replies.
Using a ladder is ok for single storey work, but on a house scaffolding is sensible and a whole lot safer, easier and quicker.
deeps said:
roofer said:
Please don't use that, it will rot the frame in 2 years. If its leaking get a proper roofer to investigate, they do exist.
Hi roofer. I'd be interested to know what you base that comment on?I've been involved with many loft conversions and have always used celotex, cut between the rafters and leaving an air void between it and the felt.
It's used extensively on new builds too, where the town house design means the roof space is living space. I know in such houses Taylor Wimpey use 3" thick celotex (bloody expensive)cut between rafters, then overlaid with 1" celotex across the face of the rafters, before plaster boarding.
Maybe you're thinking of something else?
The product in discussion here is a nasty foam , sprayed to stick to the underside of the roof and structure itself , nothing like slabs of cel;otex etc .
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