Waterseal vs. Masonry paint?

Question

It seems to be raining a lot at the moment, mostly in my kitchen...

There's a parapet wall above which is cracked and badly pointed and I think must be where the water is getting in. I need a quick fix and bought a load of Thompson's Ultra Waterseal to paint on it, after filling the cracks with a sealer.

But since the brickwork isn't visible from the ground, I could paint it instead/as well. Masonry paint does a good job of keeping windowledges waterproof, so will it do the same on the brickwork? Can I paint the waterseal on and then cover it with masonry paint, or should it be the other way around?

Basically, I'm wondering whether waterseal does much the same job as masonry paint, but just happens to be transparent. Is this right?

Lee Blaver · Accepted Answer

I also await any replies since we have the same problem. The specialist roofer says that the smooth rendered parapet wall is porous, doesn't look like it to me, but he could be right. Job for tomorrow is to hack off the existing cement render, re-render and also consider paint or waterseal...

Lee

simon beer · Answer

If you are going to re render it you could also put a water proofing agent in the water when you mix the render. The sort of thing that you would use to render a wall after a new damp course has been injected

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Lee Blaver · Answer

Good point, probably still won't hurt to paint it as well though ;)Lee

Lee Blaver · Answer

Just to follow up, I was reading the application notes on Dulux masonry paint and it claims that painting parapet walls is "inadvisable". Something about not being able to keep moisture out of the wall and possible frost damage/spalling.

Won't be painting it then ;)

Lee

Max Christian · Answer

Thanks Lee, I knew there must be a reason why none of my neighbours have done it!

For future reference, the relevant document is:

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"Painting of parapet, free standing and retaining walls below ground level damp-proof course is inadvisable. In these situations, it may be difficult to prevent moisture penetration and consequent failure of the paint coating. Painting this type of wall may also increase the risk of frost damage and spalling of the brickwork or stonework."

M

Lee Blaver · Answer

Re-reading this, I think I have mis-intrepreted it. I was under the impression that parapet wall were always on the top of buildings, but they can also be at ground level, in which cast the above surely refers only to that part of the wall below ground level?Just as confused as before now! ;)Lee

Max Christian · Answer

O! Now I'm confused again as well! I really want to use masonry paint, because the wall has lots of cracks and if I fill and paint over, it will be easy to see if/when the cracks re-open.

Thinking about it, surely there isn't a problem with painting parapet walls upstairs because all the moisture can get out downwards (into my kitchen)?

M

Waterseal vs. Masonry paint?

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