Painting cinder block walls

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  #1  
Old 07-19-06, 08:01 AM
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Painting cinder block walls

My garage has very porous cinder block walls. I want to paint them white or gray, but don't know what to use. I fear that the paint will just seep into the blocks and look lbad because they are so porous. I don't want to deal with having to apply 3-4 coats of anything either. What should I use? I was thinking of using DRY-LOCK paint that you would use in basements because it seems to have a very thick consistancy and might get the best coverage.

Should I just use a primer and then top coat it with masontry paint? Do I need a block filler? How easy / time consuming is that to apply?

My garage is 20' wide by 34' long with 7' ceiling.

Thanks in advance.
 
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  #2  
Old 07-19-06, 08:32 AM
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Block walls

Whitwash is an inexpensive coating you can make to cover cinder block. Google "whitewash recipe" to find out how to mix. Most mixes consist of hydrated lime,salt, and water. Much cheaper than paint.
 
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Old 07-19-06, 08:59 AM
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As a painter I have always used blockfill [block primer] for all above ground applications and drylok for below grade. Use a large nap roller cover and apply generously to fill the pores.

While blockfill or drylok are often left with no top coat both look and wear better with 1 additional coat of regular latex paint.
 
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Old 07-19-06, 10:24 AM
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Is blockfill easy to apply with a roller? Is it real thick like drylock? Will one coat smooth out and fill in the blocks?
 
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Old 07-19-06, 11:28 AM
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Painting cinder block walls

You probably have concrete block (normal weight or lightweight) and not cinder block, which are a different material.

Are you coating the interior or the eterior?

Are you trying to just get a different color or do you want to create a smoother finish with joints or a totally smmoth surface?

Dick
 
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Old 07-19-06, 11:33 AM
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This is a townhouse. The first story is basically the garage, and the 2 story house sits on top. The garage walls are basically the BLOCK foundation walls for the structure. I am trying to finish the inside area (garage) because the blocks are dark and dreary looking. I want the paint to brighten up the room (white or gray paint) and also give a more uniform smooth finish than the raw, rough concrete walls that are there now.
 
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Old 07-19-06, 02:45 PM
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Block fill is marginally easier to apply than drylok. Both are heavy bodied and take more effort to apply than regular paint. It is formulated to fill the pores of the block - works on both cinder and concrete block. One heavy coat [rolled out smooth] is sufficent to fill the pores.
 
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Old 07-24-07, 07:41 AM
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It's a year later but I am finally ready to do the job. I am going to use one coat of block filler, and then a standard latex paint of my choice for a top coat. Thanks for all the input.....next up is epoxy coating my garage floor after the walls are done..but I will save that for another thread!
 
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Old 08-16-07, 05:14 PM
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I got half the walls done with the block filler.....man that stuff is a real PIA to use. I had to brush it very thick and then smooth it out with a roller. It covered the blocks well but the surface is still very rough.....should I put a second coat on????

As for the topcoat, I am going semi gloss....should I use an exterior masonry paint or just a basic latex?
 
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Old 08-17-07, 05:26 AM
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Not sure I understand about the surface being rough. Did the pores in the block get filled? did any dirt get in the block fill? Did you scrape off any loose mortar prior to painting? A block wall will never be slick like drywall.

The top coat can be most any type of latex paint. Both interior paints and exterior will adhere fine. Using exterior paints indoors isn't usually recomended. Exterior paint doesn't dry as hard as interior so it may not wear as well. Also exterior paint 'fumes' aren't supposed to be in an inclosed space. Choice of sheen is strickly personal - flat, satin, semi-gloss - all will do a good job.
 
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Old 08-22-07, 08:06 AM
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Thanks for the response. The block filler did fill in the pores but the surface is still rough, I guess it is what it is...

I will apply 2 coats of regular latex semi gloss. I'll take pics once it's all done. Hope to finish by this weekend. Thanks again.
 
  #12  
Old 04-19-11, 08:05 AM
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Thank you, Marksr ,for the responses.
And for doing the hard work - reading the paint label (nearly impossible due to the use of small to tiny print and foreign languages).... reform here is a must !!
Will post again when I have more info.
 
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Old 05-11-11, 12:35 PM
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Hi, I just stumbled upon this thread. My garage is cinder block. I bought my house from a "rehabber" a little more than two years ago. To get it ready to sell, it looks like he put a quick coat of latex paint over the previously painted walls with probably no preparation as paint is chipping off/bubbling in spots in random spots all over the exterior of my garage. I've started to scrape a lot of the chipped/peeling paint of and I can see the untreated mildew stains that covered the original coat, which was subsequently painted over without treating the mildew stains.
Any advise on what I'm about to do wrong or should do differently would be greatly appreciated. Here is my game plan to fix the problem:

-Scrape off the rest of the chipping/flaking/bubbling paint
-Pressure wash the surface and let dry
-Coat walls with bleach solution on the exposed mildew stains and let dry
-(?)Coat walls with denatured alcohol and wire brush anything else I can get off of them and then rinse off the wall and let dry(?)
-Apply a coat of block filler
-Apply latex paint

Again, any advise on what I'm about to do wrong or should do differently would be greatly appreciated.

-DIY novice
 
  #14  
Old 05-11-11, 03:08 PM
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Welcome to the forums JDW!

Start with the scraping and pressure washing - you may need to do more scraping after washing. Bleach should never be allowed to dry on the substrate! Let it set but not dry and then rinse off, retreating and maybe scrubbing might be needed on stubborn areas. I doubt denatured alcohol is needed.

Block fill is only needed if the block or raw [or vary porous from 1-2 coats of paint with no blockfill used previously] If there is any chalkiness, add flood's emulsa bond to the 1st coat of paint.

As you know, lack of proper prep is the main cause for the paint's failure. I suspect he didn't remove or treat the chalk and just painted over it Paint won't bond well to chalk so the more paint you can remove, the better.
 
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Old 06-23-11, 08:13 AM
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writing surface on cinder block?

hi, i've read the entries here and am not clear on how smooth can be expected when using block filler. i was hoping to find some way to cover the square painted cinder blocks of an interior wall (not necessarily fill in the joint grooves) with something that would create a smooth enough surface to paint with chalkboard paint and write on with chalk. (would like to create a mathematical xy-plane grid.). would the block filler work well enough, or, if not, is there anything relatively inexpensive that would?
 
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Old 06-23-11, 02:23 PM
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Welcome to the forums jddins!

Block fill is intended to seal the block and fill the open pores that are in the block. It does nothing to the mortar joints other than seal them.

I've never worked with the chalkboard paint but I doubt block would be a good candidate for it. Even if a smooth coat of mortar/stucco was applied to the block it probably wouldn't be slick enough. You might be better off hanging plywood onto the wall and use the chalkboard paint on it [after priming]
 
  #17  
Old 06-23-11, 02:54 PM
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You can totally hide the mortar joints, but it takes time and skill. It the walls were meant to be smooth, they would have been laid with flush struck joints, to make a plane surface that some kind of a coating could fill the voids and create a reasonably smooth surface.

The opposite is to hire a real craftsman to plaster the wall and then do a "China coat" about 1/16" thick that is absolutely smooth, perfect and costly. - I had that is my masonry home that was built in 1917 (without a crack in the whole house) and it seemed to be a shame to even paint over it. At least they did not stain or varnish the solid custom trim and just painted it - 12" birch with added Greek dentals for the "crown molding". It was a treasure that I repected (even with the John Dillinger buttet hole on the stucco by the front door), but it is not available or remotely affordable now.

Getting a very smooth finish is easy or cheap and it takes skills. Throwing on a coating will probably not meet your expectations considering what you are starting with.

Dick
 
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