I am looking into CWI for my 1920s house, and apparently bonded EPS beads would be the best solution. However, I see a lot of references to graphite/platinum/grey beads, and a wondering if all beads were pretty much the same now, or if I should be looking for anything specific.

For instance, my local installer claims to use Evobead, which claims to have the appropriate 0.033 W/mK thermal rating, but just seems to say the beads are 'grey'. No mention of graphite. Otherwise, I need to go to a local branch of a national company for e.g. Thermabead 'carbon bead', or similar.

My normal preference would be to go for a local company.

Anybody have any thoughts/knowledge on this? Thanks.

I think there is standard EPS and graphite EPS that has graphite added, is grey in colour and is about 20% more thermally efficient.

Bricks are surprisingly porous/not waterproof so there is always a slight risk of water bridging the cavity when CWI is inistalled. I've also heard the graphite coated bead system is less likely to allow this to happen but I've not read any proper studies. If the outside of your house was rendered that should pretty much eliminate this risk.

 

Thanks both

Yes I am aware of the benefits and possible pitfalls, but was trying to get an idea if I needed to shop around for a specific bead.

 

I have now gained the impression that the beads are all pretty much the same, with the source material coming from a few big chemical names in Europe. The chemicals are 'expanded' in UK by smaller companies, which may vary in uniformity of product, before going to the installers. 

19 hours ago, Temp said:

Bricks are surprisingly porous/not waterproof so there is always a slight risk of water bridging the cavity when CWI is inistalled. I've also heard the graphite coated bead system is less likely to allow this to happen but I've not read any proper studies. If the outside of your house was rendered that should pretty much eliminate this risk.

 

I am using beads in a 150mm cavity with facing brickwork.  I am going to apply a coat of Stormdry masonry cream to stop water penetration.

On 10/01/2023 at 14:46, osprey said:

my local installer claims to use Evobead, which claims to have the appropriate 0.033 W/mK thermal rating, but just seems to say the beads are 'grey'. No mention of graphite.

 

My installer used Evobead as well. I tried analysing them with a megger to see if the graphite gave a measurable resistance but they didn't show any conductivity up to 1kV test voltage at least.

I'm pretty sure they do conduct a little at static level voltages as they don't tend to cling in the same way plain EPS beads do.

 

They look just the same as the beads I had injected this week. I also noticed that they don’t cling or behave like plain white eps, so there is something going on with the coating.