EWI vs thermal render advice

[dazzler9000]

I've been toying with the idea of getting 100mm EPS EWI on my two solid walls for a while now. My wife is concerned about the recessed windows, and I have to admit, this does bother me a bit.

This evening, I discovered thermal render systems from Proofshield, where they claim to have some thermal properties. Just wondered what anyone's thoughts were.

I find getting valid specs hard, as some display U and some R values....
I've attached an image from their PDF, anyone know if these values stack up? I appreciate it won't warm the house like EPS, but it should be cheaper, and my windows won't be tunnelled. 40mm seems a sensible thickness. According to the chart, that's a 500% increase to the R value.

https://proofshield.co.uk/wp-content/uploads/2024/10/Thermo-Silicone-A4-new.pdf

 

[endecotp]

The “untreated wall” numbers that that table look wrong. I’d expect something around 0.5 - 0.6. The benefit of their product looks less impressive in that case….

I find these numbers are easiest to think about if you convert them to Watts and then to £. “X times better” is less meaningful than “Saves £ per year”, right?

Note that PIR is significantly better than EPS.

 

[dazzler9000]

The chart I found here https://www.insulationadvice.co.uk/ti-r-values suggests 0.37, still higher than 0.18.....

It's a decent enough improvement on what we currently have. Does anyone here have any experience with thermal render in general or the Proofshield product mentioned?

 

[noseall]

The chart I found here https://www.insulationadvice.co.uk/ti-r-values suggests 0.37, still higher than 0.18.....

It's a decent enough improvement on what we currently have. Does anyone here have any experience with thermal render in general or the Proofshield product mentioned?

View attachment 411792

Never heard of thermal render. If it is not endorsed by Local authorities or architects/designers etc, then it's largely to be treated as a gimmick.

There are few 'magic' remedies that can replicate the performance of PIR with polymer render type EWI applications.

 

[dazzler9000]

I wonder if going for a 50mm EPS EWI board would be a better idea than layering up a thermal render? I know the recommended is 90mm, but I just can't sell the set back tunnelled windows to the Mrs.

That being said, I'm now reading about the combustibility of EPS and the potential for mould inside due to the building not being able to breathe. I know my house suffers from high humidity levels, but I don't know how much of that is caused by the solid walls.

 

[noseall]

I know my house suffers from high humidity levels, but I don't know how much of that is caused by the solid walls.

It's caused by human occupation.

It's remedied by ventilation.

The consequences of high moisture content and condensation forming on outside walls, cold spots etc - the remedy is insulation.

 

[dazzler9000]

It's caused by human occupation.

It's remedied by ventilation.

The consequences of high moisture content and condensation forming on outside walls, cold spots etc - the remedy is insulation.

Agreed, we do our best and I'm well aware of all of the contributing factors, but it's incredibly hard to control and much worse of damp days, hence me not knowing if I'm trying to fix a problem that's being caused by my solid walls.

I have MVHR on my list, but need to concentrate on one thing at a time.

 

[endecotp]

I wonder if going for a 50mm EPS EWI board

Why EPS rather than PIR?

 

[endecotp]

I have MVHR on my list,

Do you currently have (and use) extractors in the kitchen and bathroom? How do you dry washing?

but need to concentrate on one thing at a time.

Extractors first, if you lack them.

 

[dazzler9000]

Why EPS rather than PIR?

Costs and I've heard that it can shrink, causing cracking.

 

[dazzler9000]

Costs and I've heard that it can shrink, causing cracking.

Yes, we have good extraction in the bathrooms (100mm solid pipe in the loft connected to a 10mm extraction unit) and the kitchen has an extractor.

Washing is nearly always tumble-dried.

 

[endecotp]

I've heard that [PIR] can shrink, causing cracking.

Have you been doing "internet research"? Beware, there's a lot of nonsense out there. Have you looked at EWI documentation from Kingspan or Celotex?

 

[dazzler9000]

No doubt there is. Just had another Google and it looks like it's true, or it can be in certain circumstances. Out of my price range anyway and I couldn't find any local installers that use these types of products. Admittedly, I could look harder if I had the budget.