Is masonry paint waterproof?

[Handyman]

Is best quality masonry paint waterproof (e.g. Dulux Weathershield)? Or should I paint walls first of all with a waterproofing compound? (Here, I am talking about 15 garage units, so material cost and manpower are very significant). The instructions on the can are unhelpful about waterproofing qualities, but my local supplier assures me that it is.

Any further advice appreciated.

 

[breezer]

its not waterproof as in for use under water, but we have it outside on this house, every 5 years i do it again, just because it looks "dull"

 

[Handyman]

Dull, I don't mind, but flaking off and allowing salt-laden atmosphere and rain to get in behind the paint and attack the underlying screed, I want to prevent. How does yours fare after 5 years? And did you use "smooth" variety, or "textured" variety (and does this make a difference?)

 

[breezer]

we have the "lumpy one" (by mistake) only difference seems to be the the lumps i would say if yours does not stick its not the paint, either the surface was not cleaned first (so it can stick properly) or the surface is clean but itself has not stuck properly. if you see what i mean.

like painting a foot ball but only on the top, and i turn it round you wonder where the paint has gone (sort of)

 

[Handyman]

The surface has been entirely cleaned and reasy to go. It's not the efficacy of application that concerns me, it's the longevity of the finish I'm querying - especially in a coastal environment. Do I need to "undercoat" with a waterproofer first, or is the paint sufficiently waterproof in its own right?

 

[bizylizzie]

Hi there folks

While we are on the subject on masonry paint, can anyone suggest where I can find a dark grey masonry paint please ? I have the weathershield colour chart and B+Q also and they dont do a dark grey.

If there isnt one, would anyone recommend buying a light-grey and adding some black, or doesnt it work that way ?

 

[Peebs]

Hi
A few years back I owned a property with a rendered exterior, which we painted with a masonry paint. It lasted 5 years before it faded (did not flake). Ensure that you use a good make as cr*p ones are like water amd ae rubbish....

 

[oilman]

What are you trying to waterproof against?

Buildings should not be sealed tanks, they should BREATHE.
What do you want the paint to do apart from waterproof?
Waterproofing is the start of problems for many buildings, not the end.

 

[Handyman]

What are you trying to waterproof against?

Water?

I want to prevent water/moisture/dampness/salt-laden atmosphere from getting behind the paint, attacking the undrlying surface, and causing the paint to flake and lift. Repainting every few years is expected, but having to re-screed is a pain in the *rse.

 

[david and julie]

Don't all the decent paint makers have a technical help number on the tin?
They will advise you if you need any special primers to suit any particular job. Although they want you to buy their product's(obviously) they're very helpful.

Be better still if you could E mail them, that way you could show your customer if expensive primers were required.

Good Luck, Dave

 

[Studders]

Screwed+Fixed were doing a different type of masonary paint, can't remember the exact details (except it was dearer than the normal stuff and I think resin based), which 'sounded' very promising. Haven't got around to trying it yet tho so, I'd be obliged if you could try it and let me know so I don't waste my dosh.
No serously it did sound 'new and different' and I intend to give it a try at some point soon.

 

[oilman]

I want to prevent water/moisture/dampness/salt-laden atmosphere from getting behind the paint,.......

Forget it. You'll never win. You'll just spend loads trying. Waterproof coatings trap water. You need to allow ventilation to remove the moisture, but the modern vogue is to think you can keep water out. Well, even if you put a plastic bag over the whole building, there will still be moisture inside trying to get out.

 

[mildmanneredjanitor]

You need to use a paint that can breathe, it is when moisture becomes trapped behind paint that problems occur, it will just blister the paint off.

This is why you should never use gloss paint on masonry (like cills etc.) But you often do! The cills on my propert were all glossed and looked a real mess! After carefully chipping all the layers off, repainted in masonry paint and 5 years later still looking good! Just the rest of the outside looks like Lebbanon!

Also, never be tempted to paint on a cold, damp or wet day.

 

[jeds]

Oilman is right. You will not keep water out. Water will get in anyway, whatever you do. By waterproofing you will in fact keep it in.

Buildings rely on being able to absorb water and then freely evaporate it off. Stop this cycle by adding waterproofing to render and impermeable paints etc. and you will cause much damage.

It's true you know.

 

[Deadly Ferret]

While we are on the subject on masonry paint, can anyone suggest where I can find a dark grey masonry paint please ?

Try Leyland.