I have recently read that Celotex and any solid insulation of a similar ilk all lose their performance over time. Somthing akin to the material loosing it's gas insulative properties. After 5 years they are said to be not much better than equivalent polystyrene insulation.
I cannot find much out about it, just forum whisperings, which surprises me as I would have thought this would be big news in the building world.
I was thinking of using some foil backed Celotex to insulate a single skin utility room. It is only a small space maybe 2.5 x.2.5m square. But, based on the above, I am now thinking what is the point, why not just use the much cheaper polystyrene.
If I did would this mean I now need a vapour membrane?
Would the polystyrene be pressed up against the brickwork (which already has some form of membrane covering it)?
Or for such a small space, is a rock wool roll better?
I cannot find much out about it, just forum whisperings, which surprises me as I would have thought this would be big news in the building world.
I was thinking of using some foil backed Celotex to insulate a single skin utility room. It is only a small space maybe 2.5 x.2.5m square. But, based on the above, I am now thinking what is the point, why not just use the much cheaper polystyrene.
If I did would this mean I now need a vapour membrane?
Would the polystyrene be pressed up against the brickwork (which already has some form of membrane covering it)?
Or for such a small space, is a rock wool roll better?
Last edited: