Internal lime plaster insulation

[Danthepole]

Hello All.

Has anyone experience in using insulating lime plasters internally?

I have a few external solid brick walls I’d like to insulate internally and although I’m a carpenter and putting up a stud work frame and filling it with insulation would be the easiest and lowest cost for me, I’m thinking an insulating lime plaster may be best.

Any advice would be most welcome.

 

[aockenden]

My wife and I are in the midst of stripping the interior of all our external stone walls back to bare stone and replastering with a variety of different home-mixed insulating lime plasters / renders. We are using coarse and fine granulated cork, coarse and fine hemp shivs, and a fine perlite for our insulating aggregates, depending on the situation.

Happy to help with any questions you might have, as I’m very passionate about the value of this work to people’s lives who are suffering in cold, damp old houses.

Edit: here are some pics of the work we’re doing at various stages of completion.

 

[Lacan07]

Insulating lime is one option, you can buy it ready mixed or mix your own (hemp). The trouble is it's not very insulating, at least compared to the other option which is wood fibre board, between 60 - 100mm. If your brick walls are very flat and true WFB can be applied directly. If not a lime scratch and float coat is applied first. A 2 coat skim is then applied to finish with mesh in-between.

 

[jamest]

I would second Lacan's option. I looked into using Diathonite insulating plaster, which quotes a good thermal resistance number, but it's hard to apply and achieve the stated figures. You need to ensure it is sufficiently 'loose' (i.e., full of small voids) for if you compress it as you would a normal plaster, it doesn't work nearly as well - you basically have to use a kind of harling technique to apply it. It's also fiendishly expensive - if you make your own, it would obviously be a lot cheaper, but you would then have even less idea about how effective it is as an insulator. I went with cork board and used the Seciltek system that Mike Wye sell (other suppliers are available) and it was easy and nice to use, and cheaper than Diathonite.

 

[Danthepole]

lots of food for thought. Thank you.

I saw cork boards being used internally without any lime topcoat which I liked.

May I ask why nobody seems to use wooden battens with a insulating infill
Material?
Is it just the two different materials have different insulating properties?

Thanks again for all your helpful comments.

 

[a twig]

Depends what you are putting over the battens, often less effort just to wang some wood fibre on and skim for equally effective insulation performance and no worries about trapped moisture