Had enough of celotex!!!!!

[Painy]

Hi all.

right so as I said in my introduction I have outline planning for a small 3 bed house in my garden which I will be doing mostly myself apart from electrics.

my problem/question is can anyone recommend a foil insulation such as thinsulex which would negate the need for celotex/recticel/quintherm.

the last 2 houses we have built I've spent so many hours putting the f*****g stuff in , normally 120mm in between rafters and 40mm over top, I know thinsulex is more expensive but the time saved in labour and preserving my lungs outweighs this!!!!

my build is just going in for detail so need to meet with the architect regarding this but he is old school and will just go for celotex so any ideas would be grateful.

bit of a ramble I know but just desperate to save myself hours of celotexing

Edited July 24, 2017 by Painy
Spelling error

[richi]

Thinsulex? Is this the stuff that @JSHarris is (ahem) no fan of?

 

If all you care about is blocking radiant heat, then why not just line your roof with aluminium foil? But it can't possibly keep the heat in your house and stop it from travelling through the fabric.

Edited July 24, 2017 by richi
add

[A_L]

Remember that when you add in the voids either side of the insulation it is effectively 100mm thick. Also it is normally still used in conjunction with 100-150mm PUR

 

See BBA Cert https://www.roofingsuperstore.co.uk/user/u/files/tlx-silver-bba-certificate-roofing.pdf

[Painy]

Cheers guys I'm just wondering if there is a product on the market that I haven't heard of to be honest, I know the products I've researched you still have an element of celotex so was hoping I had missed something

[PeterW]

Go with two layers of rock wool at 95mm each and then add a 30mm overlay of PUR and you have your 0.15 for pitched. Then seal it up with membrane to stop the real leaks ..!

[Declan52]

Use high density Rockwool between the rafters and celotex over it.

[NSS]

You could always use.... On second thoughts, I'd better not open that can again 

[MikeSharp01]

What about blown in insulation there are many variants including glass wool and old newspapers or look at having your insulation pre cut to size fro you so all you do is pop it in. We have thinsulex in part of our current home as I needed to keep the section very thin but making sure it was installed correctly with air gap both sides, limited sagging and sealing the staple / nail & batten punctures was a pain.

[Stones]

Yep, rockwool / earthwool between rafters, then celotex or similar across rafters.  Perfectly respectable U values can be obtained.  Certainly worked for us and we live in a very exposed location.

[Triassic]

Cutting and fitting Celotex (other brands are available!) the worst ever job, never again. I'm getting mine factory fitter by the timber frame company, that have a large saw to cut it into the correct widths and the saw is fitted with an extract system, so no dust.

[gravelld]

If board insulation is required, why not EPS? Needs to be thicker, but better to work with and better vapour permeability...

 

But better I think to create cavities on top of roof and loose fill.

Edited July 25, 2017 by gravelld

[ProDave]

Another vote for Knauf Earthwool Frametherm 35. It's less nasty to handle than most forms of glass wool, rigid enough to place in between the studs of a timber frame and just stay there without slumping, even on a 45 degree roof, and does not need to be an absolutely perfect fit like completely solid insulation boards.  Increase your frame to 190mm and fit two 90mm layers. An extra layer of solid insulation inside or outside will get you to a good U value.  There is also almost no waste at all, unlike cutting solid boards.

 

I was going to use blown in insulation originally, but changed tot he earthwool when I found it was about half the cost, gave the same U value, and wa a DIY job saving the cost of getting it installed and meaning I could work at my own pace.