Spray Foam Roof - Urgh!

[SprayBodge]

Unfortunately I’m the owner of a spray foam roof. The survey when I bought the house didn’t flag it as an issue but soon after buying I realised it was a ticking time bomb. I should have done my research I know, but hindsight is a wonderful thing.

The loft is boarded out and has damp patches along the edges. The spray foam doesn’t extend into the eaves, only up to (I believe this is down to building regs requiring air flow/ventilation) and so the fact the damp patches extend the full length of the house on both sides of the house seem to imply this is a condensation issue. The previous owners then stuffed the eaves with fibreglass to try and sort the issue but it's clearly only partly worked.

So there seems to be two thoughts on this to try and improve my current situation:
- Seal all gaps - no warm air hitting cold surfaces around the eaves should limit condensation, at least the stuff that's visible. So probably more fibreglass insulation and spray foam to plug the gaps where the foam has shrunk.
- Add ventilation to try and get the roof functioning more like a regular one using soffit vents - presumably this could make things worse if the ventilation isn't enough.

I know the real answer long term is a reroof but that's a lot of money I don't have at the moment and I'd like to try and make the best of a bad situation. Ultimately whatever solution I do now will result in a reroof but as the roof itself appears to be in good condition, if I can get another 10 years out of it before having to do it then that seems to be the way to go.

By the way the house is 60's with felt and tiles (foam sprayed to the felt rather than the back of the tiles) so they presumably did this from an insulating point of view rather than due to a poor condition roof.

Any advice would be very welcome.

 

[SprayBodge]

 

[SprayBodge]

The above shows the worst bit where the foam has shrunk and left cracks and gaps. Looks like a pretty poor job. Easy enough to spray those to limit condensation but the edges are still going to present an issue...

 

[oldbutnotdead]

Yuck. Those companies are still advertising as well.......

First thing, you need to prevent as much as possible warm moisture-laden air coming up into the loft from the inhabited bit. Make sure the loft hatch is a good snug fit (foam draught strip), pack any holes where pipes etc come up with rockwool, fit proper covers to any water tanks up there. Also check the thickness of insulation under that boarding- if it is less than 300mm then get it up to 300mm (you may have to ditch the boarding or put it on legs if you really need it)

Then get rid of that rockwool stuffed into the eaves- that is a cold roof, it should be draughty and chilly up there with plenty of free air movement.

Finally, if you fancy an experiment, carefully try and remove the foam between 1 pair of rafters (near one of those drip marks would be favourite so you can see what is going on). I'm not sure how well a hot wire cutter would work but it might be worth a go.

 

[SprayBodge]

Yuck. Those companies are still advertising as well.......

First thing, you need to prevent as much as possible warm moisture-laden air coming up into the loft from the inhabited bit. Make sure the loft hatch is a good snug fit (foam draught strip), pack any holes where pipes etc come up with rockwool, fit proper covers to any water tanks up there. Also check the thickness of insulation under that boarding- if it is less than 300mm then get it up to 300mm (you may have to ditch the boarding or put it on legs if you really need it)

Then get rid of that rockwool stuffed into the eaves- that is a cold roof, it should be draughty and chilly up there with plenty of free air movement.

Finally, if you fancy an experiment, carefully try and remove the foam between 1 pair of rafters (near one of those drip marks would be favourite so you can see what is going on). I'm not sure how well a hot wire cutter would work but it might be worth a go.

Thank you for the reply. I've ordered some draught strips and packed some holes for pipes based on your advice. The insulation for the loft floor is only about 15cm and squished to a little less than this so not ideal.

Pulled out the fibreglass wool and the extent of the mess became clearer unfortunately. Appears that there's a lot of condensation that's running down the felt and then either dripping through a hole in the foam or if there aren't any holes in that particular area running down and soaking the fibreglass wool in the eaves. Parts of the wool are sodden. After pulling out the wool I could see some of the felt that was knackered and split and could see a rotten batten through it so at the very least the edge of the roof is going to need attention.

I've got someone coming to price for a reroof though I'm hoping it maybe possible to repair just the edges of the roof, add soffit vents and ridge vents and take the advice in your post above, though not sure how cost effective it will be just to get the edges of the roof done as that's still going to need scaffolding.

 

[oldbutnotdead]

Unless your roof is unusual, a reroof will not be much dearer than fiddling about. Since there was felt between the foam and tiles, the tiles may be reusable....

 

[SprayBodge]

Unless your roof is unusual, a reroof will not be much dearer than fiddling about. Since there was felt between the foam and tiles, the tiles may be reusable....

It's a very straightforward roof so I'm hoping that's the case. I'd rather get it redone and do away with the foam completely so I don't have to worry about it again. It's the original roof from 60's so I guess it may not be a bad thing to do even ignoring the foam problem.

 

[tony1851]

A draughty roof is a healthy roof.