Compriband Waterproofness

[Triassic]

The windows are in and the Compriband is being fitted. A piece of Compriband offcut was left outside all weekend in the pouring rain. The window fitter picked it up and commented that it was wet, he thought Compriband was waterproof.  Is it?  Confused!

[Triassic]

He’s also saying he thought it went hard once installed?

 

Having never used the stuff before, Im not sure!

Edited October 8, 2019 by Triassic

[mvincentd]

theory is that if it starts a certain thickness and its backing is peeled off it will then expand into the gap....which needs to not be larger than would require only a partial expansion of the compriband....and indeed keep a partial compression of the compriband.  If it fully expands then the compriband won't be compressed and won't achieve it's optimum capabilities of 'watertightness'.  Use the right size for the gap you have, eg; for 7-12mm gap the compriband on the roll is 5mm.  It doesn't go hard, remains spongy. It is impregnated though and I wouldn't expect it to be waterlogged like a sponge even a fully freely expanded offcut lying around......maybe cheap imitation of compriband not impregnated?  (all this is just my limited experience of using it on my one build).

[Triassic]

The piece he picked up was a fully expanded of cut.

 

Having looked at what was installed yesterday it’s nicely expanded and was sized for the 10mm gap. I can’t see it getting wet given that it’s in a small recess, set back from the face f the window.

 

As I’ve never used the product before I thought I’d ask a few questions.

[gravelld]

I only have experience of Iso Chemie Bloco One which is a similar product.

 

I've never submerged it, but when installed and in the rain try touching it - it feels tacky and seems to repel water.

 

It does not set hard, that's part of the point - it moulds to the gap over time.