Affordable celotex

[Nitro®]

Hi, could anyone please suggest an affordable alternative to celotex? It's the rigigity rather than the R value that is of interest to it's intended use.

Thanks.

[The Natural Philosopher]

high density poly foam?

[Tim Watts]

On Saturday 09 November 2013 20:41 Nitro® wrote in uk.d-i-y:

What are you basing your assumptions on?

"celotex" is availbale a lot cheaper from ebay than say, Wickes.

The price also tends to drop when you order lots, eg 10 sheets, 20 sheets etc.

[Dave Liquorice]

celotex?

Or buy seconds.

[sm_jamieson]

Yes, I've only ever bought seconds. Under the floor, in the walls. Of course everyone cannot buy "seconds" ! Simon.

[Andrew Gabriel]

If you buy nonames, be careful on the fireproofing (test a tiny offcut, outdoors).

[sm_jamieson]

Talking about that, its common to fill in gaps in celotex with expanding fo am. I set fire to a lump of foam (actually plasterboard fixing foam) and it went up with alarming ferocity. I think you can get fireproof expanding fo am though. Simon.

[John Rumm]

Depends on what you mean by affordable... last time I went to buy lots of it (nearly 10 years ago) the builders merchant quoted £27 a 8x4 sheet of 50mm. A local discount supplier provided a similar Ecotherm board at £12/sheet

[PeterL]

Recticel. Jewsons are a distributor

[harryagain]

The affordable one is seconds. Around half price. Small bashes and malforms, easily fixed with canned foam or cut off.

Google "rigid insulation board seconds"

There is little mechanical strength, it relys on the foil to give it what strength it has. So really you are down to gluing ply or similar on to the surface.

[RJH]

Sounds to be a good option - I'll take a look when I get round to doing the floors.

In a recent attic rooms project I used some Q-therm. Didn't mean to - I asked for Celotex, but that's what the builders' merchant gave me. About

60% of the price, ISTR, and very similar to work with.

I don't think the foil gives much strength - it's just bonded to the foam, not too strongly, and is after all just foil. Peels off easily enough too, so . . .

wouldn't work too well IME. I'd specify sheets without foil.

Speaking with a friend, he's using it to fill cavities below ground. I can see why, but he's relying on strength in compression (stop the leaves pushing together), and I'd have thought there may be a bridging risk. He also said you can lay flooring directly on top - doesn't sound right to me. But this was after 4 pints ;-)

[Andy Burns]

Sounds like you'd get it from the chemist's ...

[Peter Johnson]

In domestic use having 6in of polystyrene (or similar, presumably) under the floor is a Building Regs requirement.

[RJH]

With the floor resting on top?

[Adam Aglionby]

Build roads on top of EPS

[Tim Watts]

On Sunday 10 November 2013 08:20 RJH wrote in uk.d-i-y:

£22/sheet for 50mm - that's usually as good as the price gets unless you get really lucky with "seconds".

HTH

Tim

[The Natural Philosopher]

yes.

[dennis]

If you mean a concrete slab on top then yes.

[fred]

In article , Tim Watts writes

For info, that's the current one off price at wickes so should be beatable by a decent margin:

They were doing discounts for purchases of 10 or more but not now.

[John Rumm]

Its actually pretty strong in compression, and you can lay flooring directly onto it in some cases. Its standard practice with a warm deck roof for example to lay the insulation over the joists / firrings, then the deck goes straight on top of it. Anything that spreads the load well enough basically.