Anyone heard of Styrofoam for insulation.

[Bouba]

My new neighbour keeps bringing new ideas to this side of shore. He is scottish,and he has been insulating his roof rafters with something called Styrofoam.

I have seen them and they are light blueish colour,lightweight and like celotex. They are half price as well on Amazon but could not find them anywhere else.

Are they any good as insulation and used mostly in North due to cold weather,or is it waste of money buying these instead of celotex. They are 60mm thick. He got them from a medical supplier,who uses these to line their medicine boxes to maintain temperature.

 

[noseall]

Insulation is insulation, the building ain't gonna care.

However, if you are in a position where you need to satisfy building regulations then you are going to need a number or a value. If the manufacturers can provide this and that you design your vapour barrier and venting accordingly, then crack on.

I believe styrofoam is a more stable insulative product ideal for the food industry and biological applications. I'm pretty sure it is widely used in the building industry also.

 

[Bouba]

So you are saying that Styrofoam is as good as the likes of Celotex,and will do same job of insulating. This providing BR is not involved.

Would you like to shed some light on vapour barrier side. If a gap is left between tiles and insulation,is it still required.

 

[noseall]

So you are saying that Styrofoam is as good as the likes of Celotex.

No, what I said was that insulation is insulation. You may need to use thicker styrofoam or you may need to fuss about with the product that you have in mind in order to make it work both thermally and in terms of vapour barrier etc.

Would you like to shed some light on vapour barrier side. If a gap is left between tiles and insulation,is it still required.

You need to either speak to a designer or look at a web site that deals with the product you have in mind.

You may pay more for celotex but at least all the design and the u values and r values are all there to see. It's up to you how you spend your money but I know what I would sooner use.

 

[OwainDIYer]

It's very good stuff as insulation (I have a couple of inches under my floor screed), but I'd be worried about fire risks and also if it's applied to the underside of the roof then condensation and rot may become an issue.

 

[freddiemercurystwin]

So you are saying that Styrofoam is as good as the likes of Celotex,and will do same job of insulating. This providing BR is not involved.

Would you like to shed some light on vapour barrier side. If a gap is left between tiles and insulation,is it still required.

It is polystyrene so has a higher thermal conductivity from the likes of Celotex or Kingspan.

For simplicity if you had a spec that asked for 75mm Celotex you would need 125mm Polystyrene.

With respect to vapour barriers that's a bit of an odd question, you would still fit one if the spec asked for it. It makes no odds that its Styrofoam.

That said, like all polystyrene sheets it does not come foil backed, which on a Celotex or similar would act as a vapour barrier.