Render crack leaks when it rains.

[DonDonson]

Hi, I have a job were rain water is leaking through a crack on a rendered wall. the house is half brick with the top half render, previously someone has removed an outside lath and plaster wall due to it falling apart but didn't remove the bottom 6" which is the slopping drip above the lower brickwork, they put marine ply, eml and rendered it and meet the new render with the old.
From what I can see this hasn't bonded together and every time it rains water gets in through the join and is doing internal damage.
What I was wondering was, is there anything that I can paint over the crack to make it waterproof and then paint over that with a masonry paint? The crack is only a hairline crack but runs the full width of the house, you wouldn't believe that it would let water through but we have watched it after investigating the problem..

Thanks

 

[JohnD]

I saw this happen on an old rendered house, but if the downpipe hadn't beenbroken and gushing water into the crack, it wouldn't have mattered.

 

[catlad]

There is a thick water proof paint called acropol, it comes in black white and grey you may need a couple of coats. I don't think you will be able to paint over it.

 

[Micilin]

It sounds like they should have put a drip of some sort above the existing to throw the water off rather than try and marry into it ,which will always crack; or even better removed the existing and done it correctly-
I'm afraid it was not done properly and you need to address this . It's a pity that a lot of today's builders don't understand how to weather proof a building and rely on mastic etc

Painting it is not the way.

You could cut into it and put flashing on for a permanent solution.

Perhaps a 'flash band ' type product stuck on for cheaper answer.

 

[joe-90]

A photo would help.