# Cinder Block Wall



## Holland (Feb 18, 2011)

Cinder Block Wall: needs painting and Mildew treatment. Any thoughts? 

Primer needed, or directly to 100% Exterior Acrylic?


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## jacob33 (Jun 2, 2009)

I would wash it well than prime and paint. You would be fine with just paint I am sure too.


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## CApainter (Jun 29, 2007)

Because CMU is really porous and susceptible to moisture permeation, a block filler tolerant of high pH is typically spec'd as a primer. It has something to do with preventing alkaline properties of the masonry from migrating out. I think this is also called efflorvecense. Top coat can be anything.


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## Lightningboy65 (Mar 12, 2018)

Elastomeric would be a nice finish coat...just be sure you put it on heavy (to spec)...HEA VY!


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## CK_68847 (Apr 17, 2010)

Use Loxon for a primer or use loxon xp if you want to skip the primer process.


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## Fman (Aug 20, 2011)

Go old school- block fill and a top coat.


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## Brushman4 (Oct 18, 2014)

As others have said make sure you clean it well, then Block fill it with something like this http://www.ppghighperformancecoatin.../Cementitious-Waterproofing-Block-Filler.aspx
Then finish coat it with the Exterior acrylic product of your choice. If you can, have the filler tinted close to the finish color!


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## PaPainter724 (Apr 22, 2016)

Block fill it or youre gonna have a bad time. Especially when you have to use 4 top coats to fill the pores the block filler would have. 

You could use loxon but it's something like 4 times the cost and the only upside is that is slightly easier to apply.


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## Holland (Feb 18, 2011)

opening this thread for further feedback: 

Can I get away with cleaning the walls and just double-coating with 100% Acrylic Exterior Paint (maybe a primer the new concrete blocks only)? 
What would be the negatives of this approach?

The customer is...concerned about costs. They originally only wanted to paint one side of the building, and are not even painting the door. 

I usually move away from this type of situation, but I actually want this job. I painted the building next to it, and want to improve the look of this one if I can, and help the owner out a little if possible.


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## CApainter (Jun 29, 2007)

Holland said:


> opening this thread for further feedback:
> 
> The customer is...concerned about costs. They originally only wanted to paint one side of the building, and are not even painting the door.
> 
> ...


Because we are talking about paint, frankly you can put anything you want on it. I mean, look how well paint out of a rattle can holds up on freeway block walls. 

If the owner is encouraging you to dial down best practices in order to suit their budget, there's not a whole lot you can do in terms of offering any significant product life cycle guarantees, albeit the immediate outcome will likely be sufficient enough to please your customer.


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## Lightningboy65 (Mar 12, 2018)

I agree with CA on this. While not best practice, 2 coats of paint should get it to the point of looking ok, and hold up long enough for the check to clear. Elastomeric would really help fill in those holes, especially if not applying a coat of block filler. But then elastomeric is going to triple your paint cost, given its low coverage rate.

I really feel as though elastomeric is treated like a red headed step child. It just doesn't get the attention it deserves!


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## Woodco (Nov 19, 2016)

Elasto would be a great compromise. You need to put it on super thick and roll it in with at least a 1" roller, if not an 1 1/2"

I've done cinder block walls with both block filler and elasto. Not too much of a difference as far as I could tell. You'll save a coat using elasto, but you'll need a powerfull pump to push it, use the biggest tip you got, (I use a 629) spray it till its running down the wall, then backroll roll the crap out of it


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