Celotex or similar insulation?

MrsE_2

I want to board my loft, but I'm aware that it will bring my insulation depth to lower than the modern ideal. Its only to wood level now, but before I seal it in, I want to sort it out.

It would be cheaper & easier I suspect to buy the new "thinner" super insulation, like Celotex.

Celotex seems very expensive, are there any cheaper, similar options?

tlh858

There are cheaper types of insulation, but they are not as effective, so you need a greater thickness.

The answer is to increase the height of the existing timbers, so you can fit a much greater thickness of insulation.

Or dispose of all the junk up there on ebay or somewhere, so you don't need to put boards in at all.

MrsE_2

tlh858 wrote: »

There are cheaper types of insulation, but they are not as effective, so you need a greater thickness.

The answer is to increase the height of the existing timbers, so you can fit a much greater thickness of insulation.

Or dispose of all the junk up there on ebay or somewhere, so you don't need to put boards in at all.

LOL - my DD doesn't have a loft:p

RJS86

Xtratherm is a similar product and may be cheaper than Celotex, but I doubt there is much in it.

I bought a pallet of Celotex off the website below a couple of years ago and it was cheaper but you really need to be buying a lot, so it depends on the size of your loft. I was insulating loft and the insides of solid walls.

planetinsulation.co.uk

WestonDave

B&Q did some loft boards that had solid insulation on the underside so you could have insulation and boards - not sure how cost effective they work out compared to celotex or building up the joists, but its another idea to look at, as is Spaceboard which sits on the joists and can then be boarded over (seems hard to get these days but I got a load when Focus were doing a BOGOF deal on it!)

glubalub

When you say the insulation is "only to wood level" do you mean it only comes up to the top of the ceiling joists? If so this is likely to be around 100mm and so the loft insulation really needs topping up to 270mm. Celotex isn't really the answer as the loads from the boards could be transferred to the plasterboard rather than the ceiling joists and this would cause nails to pop in the ceiling. If you want to use Celotex or a similar PIR insulation you will need chipboard above and below the Celotex.

Better solutions are either to install some timber bearers or brackets to raise the loft boards such as the loft legs sold at Wickes. If the roof is a new truss roof then 100 x 50 timber nailed across the joists next to the node or connection point with 125 x 50 timbers spanning between them in the same direction as the joists, should be OK. Remember that loft boards will not take heavy loads and are only suitable for light storage.