polystyrene sheets on roof rafters.

[jw 1111]

Hi, we have just decided to install some insulation board and push it up between the roof joists. It's a 1936 built house in north London u.k. [with thanks to those who advised on this in a previous post] . The 'management' in our family now have put in a request for it to be it to be 'smartened up' a bit.

What I am now looking for is some thin type material that is easily cut so that we can staple it to the roof joists to form in effect; what is a 'white ceiling' for the loft (to cover up the joists and the insulation board installed between them). It doesn't need to have any insulation properties. It is just to 'smarten-up' the place a bit. We dont want to use plaster board since it would be too much work to cut up, and the relatively small use of the loft does'nt warrant it.

We are thinking of something like a very thin white plastic sheet (obviously polystrene would be a bit too fragile). Hopefull it will be very thin so that we that we could cut it up with scissors or a knife. Can anyone advise us on some material suitable, please. Many thanks.

[Goedjn]

Have you already stuffed the joist-bays with insulation? If not, You should investigate Homasote and similar compound building panels that combine insulation and fire-resistant surfaces in one panel. (Which would go across the joists, instead of between them.)

If you *HAVE* put the insulation in already, then sheetrock/plaster board really is your best bet. It's not as hard to work with as you apparently think it is, especially if you cut it into manageable sizes before moving it.

If you have a neurosis about the rock panels, then you could use something like Sunforger Marine Canvas (Which is available in the US in 100-yard rolls from ITEX/BANWEAR) It's fire and mildew-resistant, which doesn't mean it won't mold and burn, just that it's not quite as eager to do so as regular canvas. I suspect it's some sort of boric acid treatment. The canvas won't meet code, but it's better than either exposed insulation or stapling up old refridgerator boxes.

If you're cheap, and don't care about either meeting code or burning yourself to death, use white muslin, after giving it your own boric-acid/borac bath in your tub. or using a commercial fire-retardant on it.

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[jw 1111]

Very many thanks Goedjn. We have not yet put in the insulation between joists so will now find out about Homasote.

[jw 1111]

Found quite a few references in a google search of Homasote in model railway enthusiasists newsgroups who use it as a 'base' board for train tracks in outside garden sheds. There is a lot of talk about it being prone to movement in changing humidity and also it can sag if joists are more than 16 inches apart. Guess this might mean I have to keep looking. Or any further suggestions please?

[Goedjn]

Homasote is a company that makes a number of products, mostly out of recycled cellulose. What you're probably reading about is their grey fiberboard, which is used under floors and behind sheetrock for insulation and sound-control. They've got a whole catalog's worth of stuff at

SOMETHING in there ought to work. Failing that, you might look at structural insulated panels (SIP) which are a sandwich of fiber-board and foam insulation. As much of a pain to work with as sheetrock, but again, insulating and surface at the same time.

[jw 1111]

Many thanks and thanks to all. I have found some 'kingspan thermopitch' panels. (foam between two sheets of aluminium foil) and am now in the process of putting them up.

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