Cavity wall trays

[pabsy1927]

Hi all, looking for a little help and apologies in advance if this doesn't make sense! I recently had a flat roof extension built at the back of the house and opened up the previous back wall into the new space. I have since had trouble with water coming through where the rsj is. The builder is blaming my original external wall above the extension which is brick face, he says it needs to be rendered. I am convinced it relates to the cavity trays, or lack of them. He is arguing they were installed but are lead, not like the ones I've seen on line. Looking through the weep holes, which fell out! I can see that the lead flashing that goes over the first brick above the extension just seems to go back into the cavity, it looks pretty much horizontal and I cant see if it hits the internal skin. Question I have, is that is using the lead flashing a suitable cavity tray? Does this week right? Thanks in advance.

 

[freddiemercurystwin]

Nobody in their right mind would fit lead cavity trays, sounds like he's feeding you a load of baloney, he should have installed a proper cavity tray and that's still the solution probably. Brick walls are not rain proof.

 

[pabsy1927]

Thank you, that was my thought. My other worry is that the building inspector, who only visited once, has said to me lead is the best solution. Him and the builder are coming next week to look at it but worry they are close and won't give me an independent view.

 

[freddiemercurystwin]

I don't understand why you'd fit lead if you're going to all the hassle of removing brickwork anyway. Private inspector?

 

[pabsy1927]

I'll try and take a photo tomorrow of the lead flashing tomorrow, but yes going to ring a few to see if they can come out too

 

[johnny2007]

Surely a private inspector (builder's mate).

 

[pabsy1927]

Surely a private inspector (builder's mate).

No the inspector in question is the appointed council one

 

[freddiemercurystwin]

I'll try and take a photo tomorrow of the lead flashing tomorrow, but yes going to ring a few to see if they can come out too

Ring who exactly?

Any photos the builder has of the installation would be good (I bet he doesnt have any).

 

[freddiemercurystwin]

No the inspector in question is the appointed council one

Kind of surprising TBH, be interesting what they say.

 

[pabsy1927]

Ring who exactly?

Any photos the builder has of the installation would be good (I bet he doesnt have any).

I was going to call a private building ng inspector. He wouldn't haven't any photos. Here is a view from what I can see. I've taken the silicon secured weep hole out and can see lead going back into the cavity but doesn't look high and can see rubble too so might be the issue?

 

[freddiemercurystwin]

That's not a cavity tray that's a lead flashing, there should be proper cavity tray fitted that sits on top of the lead flashing eg: https://cavitytrays.com/product/type-e-cavitray/

 

[pabsy1927]

That's not a cavity tray that's a lead flashing, there should be proper cavity tray fitted that sits on top of the lead flashing eg: https://cavitytrays.com/product/type-e-cavitray/

Thank you for your help, that's exactly what I thought just wasn't 100% sure

 

[noseall]

cavity tray

I thought just wasn't 100% sure

cavtray2.jpg

• noseall
• 19 Jan 2024

cavtray.jpg

• noseall
• 19 Jan 2024

 

[cdbe]

Don't call any more inspectors. It's possible the water is coming in between roof and wall due to incorrect flashing but more likely a cavity tray issue - if you had two steels in the opening the water is likely to show between them if it's penetrating the wall above and running down the inside of the outer skin. You could remove a small area of plasterboard from the wet area in line with the cavity to give everyone a better idea of what's happening in there.

However, it's an issue for your builder - he should have either fitted a cavity tray or adequately waterproofed the wall above - it's a one or the other thing, not neither. Building control won't sign it off it's letting water in.

An old fashioned lead cavity tray:

No-one bothers with it any more due to the cost of lead.