loft insulation

[antje]

I am considering a 'rigid foam insulation' system, but have been told by a neighbour that there may be a problem with lack of ventilation affecting the timber. I understand from the contractor, that ventilation will be maintained at present levels, but am wondering if anyone has any experience with this type of system.
Many thanks, Antje.

 

[masona]

Where is this insulation going, ceiling joists level or roof rafters?

 

[antje]

Hi,
the rigid foam is 'spray applied' to the underside of the roof, locking the tiles into one solid structure, guaranteed for 25 years. This is what the brochure says. The rigid foam is of a 95% closed cell construction; and they say they leave ventilation at the eaves. They also state that this system allows the timber to breathe, as the foam has the same degree of breathability as wood.

On paper this sounds really good, but in view of the comments made to me, I am a little worried. With many thanks, Antje.

 

[masona]

Don't do it

See this

 

[antje]

Thank you very much indeed for this info. Had not considered the possibility of moisture being trapped and harming the timbers before this is spotted, and all the other implications when it comes to repairing such damage.

So, will look at more conventional methods for this particular job.

Many thanks again, Antje.

 

[oilman]

Hi,
the rigid foam is 'spray applied' to the underside of the roof, locking the tiles into one solid structure, guaranteed for 25 years. ............

25 years is nothing in the life of a building, but if you have to fix something, 2" thick glue can be a bit of a bugger. what about this ? And you can put it against the roof.

 

[Freddie]

Hi,
the rigid foam is 'spray applied' to the underside of the roof, locking the tiles into one solid structure, guaranteed for 25 years. ............

25 years is nothing in the life of a building, but if you have to fix something, 2" thick glue can be a bit of a b*****r. what about this ? And you can put it against the roof.

Oilman you cant anymore you are supposed to have a void so air can travel up over your insulation under the tiles/slates they would be better with Kingspan there----but keep on pushing the sheeps wool

 

[oilman]

Doesn't apply to sheeps' wool as it can absorb and release moisture, (condensation); something mineral wool can't do.

 

[chappers]

well said oilman 25years a properly laid roof should last over a hundred.
The original poster would be better off using either celotex or tri-iso super nine