Lime Plaster for breathability and insulation

[robot enthusiast]

Hi all, 

 

I currently have a portland cement render on the external walls of my house, and i want to remove it and replace with a breathable product. Pretty tight for space in some areas so EWI unfortunately, and i'm not sure its fully breathable. If i could use a plaster product that was breathable and gave good u-values this would be even better. Does anyone know of any products or had experience with any here? 

 

Many thanks in advance.

 

 

[Temp]

Welcome to the forum.

 

I'm not an expert on insulating render but there are limits on how effective any thin insulation can be due to the basic properties of materials. Aerogel is expensive and not easily incorporated. PIR is probably second only to Aerogel and typically 50-60mm is needed used to achieve only reasonable u-values. If building again I'd be looking at 100mm+. So don't expect miracles from any render alone.

 

Is it a cavity wall or solid wall? 

[SimonD]

You could have a look at Seciltek ecoCork Insulating render as a potential solution. I've used the ecocork internally and will be doing a long wall with it in my current project - weird stuff to work with as it's literally like pasting cork granules to the wall. Here's a link: https://www.mikewye.co.uk/product/secil-ecocork/

[robot enthusiast]

4 hours ago, Temp said:

Welcome to the forum.

 

I'm not an expert on insulating render but there are limits on how effective any thin insulation can be due to the basic properties of materials. Aerogel is expensive and not easily incorporated. PIR is probably second only to Aerogel and typically 50-60mm is needed used to achieve only reasonable u-values. If building again I'd be looking at 100mm+. So don't expect miracles from any render alone.

 

Is it a cavity wall or solid wall? 

Yep - solid double brick walls with no cavity. 

[robot enthusiast]

3 hours ago, SimonD said:

You could have a look at Seciltek ecoCork Insulating render as a potential solution. I've used the ecocork internally and will be doing a long wall with it in my current project - weird stuff to work with as it's literally like pasting cork granules to the wall. Here's a link: https://www.mikewye.co.uk/product/secil-ecocork/

Thanks will take a look. I heard renovating plaster can work but that was from a jobbing plasterer who was likely sniffing for work  - I would need to do some more reading on all of this. 

[Roger440]

They sell much the same as mike wye, but rather more info on the website: https://www.lime.org.uk/products.html

[Temp]

Are  building control are involved? If so best not tell them that the new render has insulating properties as they may want the upgrade to meet better standards than can be achieved without EWI or IWI.

[SimonD]

1 hour ago, Temp said:

Are  building control are involved? If so best not tell them that the new render has insulating properties as they may want the upgrade to meet better standards than can be achieved without EWI or IWI.

 

Depending on how to look at it, part L does thankfully contain numerous caveats to allow for flexibility here, and generally that u-value should not exceed 0.7 on improved elements. In some cases you can actually get away with more. IWI or EWI definitely best if you can do it mind you.

[Roger440]

5 minutes ago, SimonD said:

 

Depending on how to look at it, part L does thankfully contain numerous caveats to allow for flexibility here, and generally that u-value should not exceed 0.7 on improved elements. In some cases you can actually get away with more. IWI or EWI definitely best if you can do it mind you.

 

Or dont tell them. I find this approach much easier.

[robot enthusiast]

Thanks all for some great help. I'm going to get my head into some more research and call some of the companies, very much appreciate your knowledge and helpful links. Thanks.