how to paint cinder blocks to last longer

[CNX69]

Never painted Four year old fence needs update. 

Friends tell me get professionals and they will do for you. Yes, easy buy I have a lot of time just need knowledge. 

HomePro told me to get mold remover, primer and paint. 

I am just wondering how long will paint last in this climate. 

 

 

[bankruatsteve]

Scrub with wire brush to remove mold and loose bits.  Clean with a house detergent and water using a soft brush.  Use premium grade latex primer diluted by 10% water.  2 coats of high grade exterior color cleaning any dust first.  10 years from now it will look the same.

[ChipButty]

As said above, make sure you use a good primer and buy a good brand of paint I always buy Dulux weathershield it will last and not wash off, certain part of my house gets hammered in the rain after 5 years it's still ok and you can wash it down 

[Morakot]

On a side note: if your entire wall looks like this than this is a well-done masonry job. 

 

It's pleasing to see that there are proper craftsmen out and about doing good work!

[Morakot]

Quote

HomePro told me to get mold remover, primer and paint

 

You'd end up using a ton of (expensive) primer with a mediocre result.

 

I'd use a super thin coat of cement-based skim render applied with a roller and smoothed with a Venetian trowel as a base. Paint on top of this after a coat of primer.

Edited November 24, 2020 by Morakot

[CNX69]

ThankYou for all practical advises. 

 

I can scrub/clean and I can do "cement-based skim render applied with a roller". It it possible to apply some clear coat or a sealer to have gray cement look. 

 

[CNX69]

Done by Myanmar's laborers without contractor 

 

[CNX69]

Next house fence done about 5 years ago by Thai contractor

 

 

[Morakot]

6 hours ago, CNX69 said:

ThankYou for all practical advises. 

 

I can scrub/clean and I can do "cement-based skim render applied with a roller". It it possible to apply some clear coat or a sealer to have gray cement look. 

 

 

A 25 kg bag like this should cover about 20 sqm (1 mm tick): https://www.jorakay.co.th/en/product/crocodile-skim-coat-sanded.html

 

Standard colour range: grey or white. If you want to keep it grey, you may not need coats of paint or sealer. Although they may  slow down the turning green a bit.

 

PS: Render like this is normally put on with a trowel. But you can use a roller if you add a little bit more water and moisten the surface. The joints will still be visible if you do it like this.

Edited November 25, 2020 by Morakot

[CNX69]

5 hours ago, Morakot said:

 

A 25 kg bag like this should cover about 20 sqm (1 mm tick): https://www.jorakay.co.th/en/product/crocodile-skim-coat-sanded.html

 

Standard colour range: grey or white. If you want to keep it grey, you may not need coats of paint or sealer. Although they may  slow down the turning green a bit.

 

PS: Render like this is normally put on with a trowel. But you can use a roller if you add a little bit more water and moisten the surface. The joints will still be visible if you do it like this.

 

Thank You very much for useful info and link. I will try and post pictures. 

 

[David B in Thailand]

All good advice given. Those blocks are going to "suck up" the primer even if cleaned. You may heed the heed the advice on skim coat. It will pay off in savings of primer. 5 gallons of Nippon Flex Shield primer is about 2000 baht a bucket at Global House or Thaiwatsadu. That primer will cover 150 to 170 square meters of wall surface if it is rendered. It never hurts to fill in cracks on fences. Dulux Weathershield super primer is also a product I have bought and been very satisfied with. 

[Daffy D]

If the blocks haven't been skimmed with a layer of smooth cement don't think you can just run a paint roller over it.

 

You will be spending most of your time getting the paint brush into all the little holes and crevices in the basic cement block that the roller just skips over  

[bankruatsteve]

Yah, I think I would go with a paint brush.  But don't know how big the job.

[HighPriority]

2 hours ago, Daffy D said:

If the blocks haven't been skimmed with a layer of smooth cement don't think you can just run a paint roller over it.

 

You will be spending most of your time getting the paint brush into all the little holes and crevices in the basic cement block that the roller just skips over  

32mm or larger lambswool roller will do the job.

my biggest mistake the first time I painted these blocks was to keep recoating before the first coat had dried, it just kept sucking up the primer...

Prime, let it dry and off you go ????????

[kamalabob2]

I prefer semi gloss or sheen paint for exterior walls. I have recently bought "mistake color mix" TOA Supershield semi gloss acrylic latex paint in Buriram to paint boundary fences at my wife's village home. I've been able to give her family 5 gallon buckets of TCI matt ceiling paint that cos tme 500 baht for 5 gallons.  I believe most every builders merchants store in Isaan has some mistake color mix paint they sell at a discount from time to time.