Painting Breeze Block?

almostthere12

We have a small back garden with a breeze block wall that is around 60sqm in total and 3m in height in parts. I was thinking of getting it rendered but that would cost around €2.5k. Looking into the idea of painting it, using a primer first and then a masonry paint. Anyone know if this can turn out well or it can still look fairly crappy?

looksee

It depends on how critical you are. I've done it because the ancient grey blocks were dark and gloomy, so I painted them white. They ended up kind of white, kind of patchy but definitely brighter. They could end up annoying you more than the original grey.

I used a roller and masonry paint, two coats, it eats paint and the result is honestly not great but could be better than what you have. It may work better with a sprayer as the paint would get into all the little holes better, someone else might have experience of that.

almostthere12

Was thinking of going with a primer as well so was hoping that might help and grey so it wouldn't be as patchy. I am probably going to put up a trellis with creepers on half of it so if I could get away with a decent enough job it would save me a lot of cash. Very hard to find any decent photos of what it turns out like online.

Mikros

Also just be aware that if you do paint the wall it makes it a lot more difficult (read expensive) to render it in the future if you change your mind.

almostthere12

https://www.boards.ie/discussion/comment/120766541#Comment_120766541

Thanks, didn't know that. Might do it on the wall at the side of the house first so as a tester. This will be covered with a lean-to in time so not too pushed if I get it rendered or not.

almostthere12

Finally getting around to starting a section of the wall, going to start with using filler at the weekend and then towards the end of next week will use a primer and a give another 2 coats on top of that. It's going to be white.

I was in Pat McDonnell Paints over the weekend and the guy said to water down weathershield brilliant white to use as a primer. Is that the norm or does a dedicated primer do a better job?

standardg60

https://www.boards.ie/discussion/comment/120983074#Comment_120983074

https://www.woodies.ie/dulux-weathershield-stabilising-primer-5l-560998

I always use this, it's solvent based so gives a really good seal.

Why paint shops and painters advise watered down paint as a sealer when the actual manufacturer has a separate product designed for the job is beyond me. Why would you even water it down? Surely that's worse.

SEPT 23 1989

Hang on until you have the cash to render it

painting will never look right

SEPT 23 1989

https://www.boards.ie/discussion/comment/120983151#Comment_120983151

It’s called a mist coat and it works

standardg60

IMG_20230815_205348_849.jpg

This was sealed with the above primer 20 years ago and painted, it's had the odd top up though not for a while given the Virginia creeper. I'm happy enough with the bare block look.

Ceepo

The reason paint shops and painters recommended watering down the 1st coat is to allow the paint to "absorb into the surface, this will "seal it" and allow better adhesions for further coats, this is particularly relevant for the OP case as the block will absorb approx 2x the paint for the 1st coat. If you are applying paint "neat" there s more of a chance that the paint will only sit on the surface and eventually peel off, The watered down paint will also be "easier' to work into any holes in the block work. Stabilising solution is a great product for it's intended purpose, which is" flakey paint or dust/chalky surface. Hense the reason why they wouldn't use it for priming.

standardg60

https://www.boards.ie/discussion/comment/120983257#Comment_120983257

Sure it might absorb into the surface better and allow for less paint to be used on subsequent coats but does it prevent moisture from penetrating from the other side of the wall causing flaking?

Nope.

Ceepo

https://www.boards.ie/discussion/comment/120983301#Comment_120983301

I've outline the reasons why paint shops, usually who have very experienced staff (as Pat Mc's does) and indeed painters with vast amount of expertise handed down over the year's recommend using a watered down 1st coat. Of course there are other reasons which would more for the exterior of house's, the main one being "it doesn't allow for the building to breathe".

Anyway OP, you can have a read of below and make up your own mind

https://decorator.uk/stabilising-solution-when-to-use-it-and-when-to-not

almostthere12

Thanks for all the replies, sounds like I can go with the watered down "primer". Going to be interesting how it turns out!

Get a paint sprayer, it'll make your life far easier painting breeze blocks.

standardg60

https://www.boards.ie/discussion/comment/120983460#Comment_120983460

Sorry, and I'm not having a go, just debating the issue. Is not the point of rendering to create an impermeable surface to stop the passing of moisture? Why would it be breathable? If it allows moisture to escape from inside a dwelling does that not compromise it's intention of keeping moisture out?

My point is that years of expertise being handed down is nothing more than repeating what you've been told to say. It doesn't mean it's right in the first place.

It has simply never made any sense to me that painting a boundary wall with just paint will not result in it flaking off if it hasn't been sealed from moisture penetrating from the other side.

Ceepo

There's nothing to debate really. As I said, stabilising solution is a good product, for it's intend purpose. It is a solution to a problem, so I wouldn't be using it unless I had the problem in the first place. So unless OP has chalky surface of flaking paint work it's not necessary in this case.

Just to add, walls need to "breathe" this allows them to dry out if there is moisture in them, this can be form the inside of the building and not just the outside, otherwise you will get mildew and possibly flaking paint over time. Most walls will have moisture in them at some point and this need to disapate some how. This is also stated in the link I provided earlier.

" My point is that years of expertise being handed down is nothing more than repeating what you've been told to say. It doesn't mean it's right in the first place."

I don't agree with this statement at all. The vast majority of trades people have gathered the expertise not just from being "told" but also by years of solving problems, learning on the job by learning what works best and when is the best time to use that solution.

And just because it doesn't make sence to you, doesn't mean it's wrong.