Cavity trays

[freddiemercurystwin]

https://www.labcwarranty.co.uk/blog/weep-holes-in-rendered-walls-when-are-they-required/

 

[John D v2.0]

Fair enough, our architect still insisted the builder fitted them for us, but I wasn't sure if was completely necessary. Sounds like he was right!

 

[freddiemercurystwin]

https://www.labcwarranty.co.uk/blog/weep-holes-in-rendered-walls-when-are-they-required/

 

[stuart45]

Just makes sure the spreads don't fill them up.

 

[^woody^]

Render isn't impermeable so a small amount could escape over time. If render were impermeable, presumably water wouldn't get in so it would only be condensation anyway.
Even Encon, who have an incentive to sell more weep vents, say there's no need in rendered walls:
https://www.encon.co.uk/sites/default/files/products/downloads/rytweep_datasheet.pdf
View attachment 134323

Has the NHBC changed their mind after 12 years?

Anyway, the thing is it's bad practice and IIRC, several BS's relating to trays, render and workmanship mention that weep holes are necessary to deal with potential failures in any render, cavity condensation, or a partcular render type.

The question remains, "How does water get out of the cavity?". "Render should keep it out" is not really the answer.

 

[noseall]

Rendered wall with cav tray. And weep vents, left hanging out the wall to deal with the render thickness.

Scaffgone1

• noseall
• 15 Jun 2015

Untitled

• noseall
• 14 May 2015
• 2

 

[nicola armstrong]

Thanks for all the advice. I spoke to the builder and we will go for DPC as a cavity tray and fit a couple of vents just to be safe.

Thanks again, very helpful.