Concrete Floor Insulation Recommendation

[craig1234]

I built an extension around six years ago and had 100mm Jablite under the slab as insulation. This was passed by Building Regs (full plans) but when the inspector came to check before the pour he said we don't use Jablite anymore! Luckily when I pointed out that this had been signed off he let it go. So, I am now building a new extension and would like some advice on what type of insulation people would recommend these days under a new concrete kitchen floor - Celotex XR/GA4000 perhaps?

 

[DevilDamo]

A 100mm rigid board of most manufacturers would normally suffice for an extension, i.e. Celotex, Kingspan, Xtratherm, Rectiel, etc... If using Celotex, use their online u-value calculator to check the thickness for your P/A ratio.

 

[^woody^]

You can use Jablite, only you will require more of it

 

[craig1234]

It was strange when the inspector saw the Jablite as it was all laid so he wouldn't have been able to tell the thickness of it - he just immediately said "we don't use that anymore". Anyway, will look for an alternative along the lines as suggested by DevilDamo

 

[^woody^]

Perhaps some needs to tell Jablite then

 

[diytry20]

Why does it matter what brand it is? Surely if thickness and specs are similar does it matter?

 

[Notch7]

Why does it matter what brand it is? Surely if thickness and specs are similar does it matter?

theres a big difference bet Jablite and PIR

in terms of PIR the manufacturers all seem to have ones for walls, ones for floors, one for roofs

Ive never seen or heard a builder do any more than order whatever his fav merchant has on the shelf, whatever brand

 

[^woody^]

Why does it matter what brand it is? Surely if thickness and specs are similar does it matter?

That's right. The OP's building inspector seems a bit of a div.

 

[frutbunn]

You can use any insulation material you like as long as it is suitable for the location in which it is to be used, however this may mean excessively thick quantities may be required.
To be honest I can't remember the last time I saw Jablite apart from the compressible stuff they use in founds to accomodate clay heave.