isover hi-cav32 vs Dritherm32

[crispy_wafer]

Having a discussion with a builder about our cavity wall insulation, he's recommending isover 32, and I'm looking a dritherm 32 as that appears to be a well used, and recommended cavity batt on this forum. 

 

I've looked briefly at the spec's and to my untrained eye they look identical.  Only the price of the Isover stuff seems to be that much greater, so I'm thinking I must be missing something.  I'm using insulationshop.co as my reference but other retailers have similar price difference.  If I can save a few pounds here and there then I'm all for it.

 

What say the buildhub experts?

[Temp]

Appear near identical. Same insulation properties.. 

 

Found a thread here..

 

http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=11199

[PeterW]

Isn't Isover glass wool and DriTherm rock wool..??

[Temp]

https://www.knaufinsulation.co.uk/products/glass-mineral-wool/earthwool-dritherm-32-ultimate

"Knauf Insulation DriTherm 32 Cavity Slabs are non-combustible, Glass Mineral Wool cavity wall insulation slabs. "

 

 

[Moonshine]

Interested in this, what is better / easier to install, glass or mineral?

Doesn't glass irritate / scratch the skin, or do both?

Edited February 6, 2021 by Moonshine

[ADLIan]

They’re effectively the same product . Other manufacturers also available 

[Tikka]

Which one did you go for? I’m in the same dilemma

[SteamyTea]

I just had a look that the thermal properties of glass and basalt.

Glass has a conductivity between 0.9 and 1.2 W.m^-1.K^-1.

Basalt 0.03 and 0.04 W.m^-1.K^-1.

But that is only part of the story.

Density, and therefore the ratio between fibres and air (which does the real work), water absorbing, combustion temperature and flame spread, insitu slumping and cost are important.

They will both make you itch.

[torre]

I've used both, the Isover is much more of a slab and very easy to cut accurately with an insulation saw, but itchier to handle and sheds more small fibres into the air. Dritherm is more like wool, much nicer to handle, but somewhat harder to cut accurately.

[ADLIan]

The 2 products are the effectively the same, glass mineral wool. The difference being the processing additives, binder & colour (which only accounts for something like 5% of the product).

 

@SteamyTea The thermal conductivity of basalt, as a rock, is 2 W/mK (ish).

 

Basalt is also much denser then glass which is part of the reason that stone wool is approx twice as dense as glass wool for the same thermal and acoustic performance. The mantra of 'denser = better' from one of the stone wool manufacturers is bullsh*t. They're just different mineral wool products with similar applications.

[SteamyTea]

7 minutes ago, ADLIan said:

The thermal conductivity of basalt, as a rock, is 2 W/mK (ish).

Yes, I think my search picked up the value for basalt wool insulation ((expletive deleted)ing AI results).

9 minutes ago, ADLIan said:

processing additives, binder & colour

Is glass wool emulsion bound like chopped strand mat (eglass) is. If so, that would account for the itching. Powder bound CSM is not so itchy.

[ADLIan]

Binder is added just after glass fiberisation (web search will show process in detail). Binder is heat cured to bond fibres in a ‘loose’ matrix hence air can be trapped. Any irritation is primarily from the fibres though newer technology produces ‘nicer’ fibres. URSA and Knauf probably take the lead here.