Missing Cavity trays

jollyj1984

Hello,

Just moved into a property and noticed the wall above the extension has no weepholes suggesting missing cavity trays. 

No signs of any leaks below but is this likely to cause any issues? It's a 20 year old house

stuart45

Sometimes the weeps can be hard to spot. 
However, even if there are no trays it's not always a problem. Depends on how exposed the wall is to driving rain.

jollyj1984

It's west facing and on occasions it has appeared absolutely drenched during the winter storms. 
 
It's in Coventry so it's a low risk area of driving rain apparently

How easy does water get through a single skin wall with good pointing and in what volume? 

stuart45

The Building Research Establishment did some tests on single skin walls some yeas back with different types of walls. One of them looked OK from the face side, but the perp joints were only half filled which was quite common on site. With this wall it took about 20 minutes to get through with a sprinkler aimed at it. 
A wall with the perps fully filled took over an hour.
If you are not getting any problems inside I wouldn't worry too much.

jollyj1984

I knew brickwork was porous but didn't think they were that bad! 

Did that test factor in wind? Or just sprinkler? 

If I have any problems in the future do builders retrofit cavity trays ?

stuart45

It was done to replicate driving rain. Some bricks are more porous than others, but the perp joints are usually the first to let the water in.
I live in the West Country which has quite a lot of driving rain. I did find on another forum some years ago that a few bricklayers in the Midlands were doubting the need for trays and weep holes. 
However a few years ago when the whole country seemed to get a session of prolonged driving rain they seemed to change their ideas.
They are usually a pretty simple job to retro fit. 
You might have something like these in the joints, which can be really hard to spot.
Pack of 50 Timloc InvisiWeep Terracotta Red Tunnel Low Profile External Cavity Wall Weep Vents: Amazon.co.uk: DIY & Tools

jollyj1984

I guess there is no evidence in this house of any problems over the last 20 years so I'll just keep an eye on it. 

I hate the idea of relying on the rain not being prolonged to stop a potential leak. Makes me feel out of control. 

Is it quite common for builders to miss/forget cavity trays? 

stuart45

I think it used to be quite common in your neck of the woods. It probably would have shown any problems by now. Possibly in the future if the pointing gets really bad.

EssexExile

Us people living in older houses don't have cavity trays and weep holes, we seem to manage.

Tucker

I have seen plenty built without them and I think because they are quite tricky to fit, some take the easy option and don't bother. 

I had the cavity trays fitted in mine but it's not done without problems. I know my bathroom window above the tray never open and closed properly afterwards and it clearly dropped a bit on one side with it being fixed to the outer skin and several courses of brick were removed and refitted below it, so it was obviously unsupported at some point. 

casper_gutman

Maybe I'm missing something, but surely the point of cavity trays is to close a wall cavity and stop water from flowing down inside. But didn't you say you had single skin walls...?