aerogel & vapour control layer

[user256]

Hey looking for a little advice here. I'm looking at insulating the floor of a traditional Scottish cottage and looking at aerogel as a possible solution to minimise loss of room height, the product I'm being recommended is the e-therm-ultra, however this does list a vapour control layer which immediately gave me pause.

Anyone got any experience / able to advise on this?

 

[aockenden]

The link won’t load for me on my phone. What is the existing flooring system you’ve got in the cottage? Is it a solid floor or suspended timber? What are the layers proceeding from the existing surface that you stand on all the way down to the soil surface? Have you ever heard of an insulated limecrete floor?

 

[erikwoolf]

Hey looking for a little advice here. I'm looking at insulating the floor of a traditional Scottish cottage and looking at aerogel as a possible solution to minimise loss of room height, the product I'm being recommended is the e-therm-ultra, however this does list a vapour control layer which immediately gave me pause.

Anyone got any experience / able to advise on this?

We used aerogel in small areas where space was limited and wanted to avoid cold bridging such as between the wooden staircase and the solid brick wall. My impression is that the material is advertised as breathable by the manufacturers but probably worth looking at the actual specs of this product you chosen to see how it compares with other floor types insulating materials.
Do you have a suspended timber floor? Most systems that use woodfibre or hemp etc recommended a VCL but not everyone is 'sold' on the usefulness of adding one.

 

[user256]

hey aockenden & erikwoolf, thanks for the replies! The floor in question is solid (this part of the cottage dates back to the 1700s) so there's basically no way to insulate underneath without the price reaching rebuild levels. I looked at insulated limecrete but the issue is ceilings height - they are reasonable enough at present though would be on the uncomfortably low side if we were losing 200mm+ hence my interest in aerogel.

 

[aockenden]

hey aockenden & erikwoolf, thanks for the replies! The floor in question is solid (this part of the cottage dates back to the 1700s) so there's basically no way to insulate underneath without the price reaching rebuild levels. I looked at insulated limecrete but the issue is ceilings height - they are reasonable enough at present though would be on the uncomfortably low side if we were losing 200mm+ hence my interest in aerogel.

Yeah I don’t think there’s any case to be made for laying an insulated limecrete floor ONTOP of your existing solid floor to begin with, it’s not really the way they’re designed to be installed. With that option you dig up the existing flooring and dig down enough so that you don’t lose any headroom vs the original once you’ve rebuilt up to the final finished floor level.

I know almost nothing about aerogel (and even less when it comes to its applications for insulated floors), but I generally would caution you against just slapping another layer ontop of what may be inherently inappropriate underlying layers. Even if your new layer of whatever IS appropriate for your old house, it likely won’t behave the way it should if it’s layered ontop of inappropriate stuff.

I believe in truly solving the deep underlying problems related to fabric and infrastructure of the house, but that’s just me. Btw, I’m right there with you on the impossible decisions to be made when living in a problem house while renovating. I know the suffering of that.

 

[eco-refrofit]

I'm also looking at aerogel for similar... I understood it was possible breathable but certainly vapour permeable and building regs these days want a layer to prevent damp under any insulation... I presume to prevent rising damp so maybe that's what is in the instructions (file won't open for me).

I think we'd do a thin vapour control layer and probably liquid tanking since ground floor is a step below outside level and there's no damp proof course. VIP floor insulation looks similar but it's rigid and I think aerogel blanket would be better, especially run up slightly behind skirting boards to avoid cold bridging. Even without the insulation the floor needs lowering a little.