painting over old drylock

revheckJune 13, 2006

I want to paint my basement walls, which currently have several coats of old pealing Drylock.

I would like any recommendations on the proper way to prep the walls and paint. Do I need to scrape off the existing paint? Prep with muriatic acid or bleach? What kind of paint do you recommend?

I do not plan to finish the basement. I just want it to look clean, bright and dry.

A few issues:

1. At one time, the basement had water problems, and there is efflorescence on the walls. But the previous owner installed an interior french drain system and sump about 3 years ago, and I just finished extending all the downspouts and sloping the exterior grade

around the outside foundation. And we run a dehumidifier in the summer. So the basement is now dry and no mold.

2. There are also some horizontal cracks in the foundation. I consulteda structural engineer when we first bought the house,. He said they are due to frost heave and are common in our area. Because they are not too

big I did not need to worry, unless they grow. I've been monitoring and they are not growing.

I'm hoping I can just fill the cracks with caulking or hydro cement before painting.

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Sorry can't offer any advice, but this doesn't sound reassuring to folks depending on DryloK to solve their moisture problems, or even as a preventive measure.

I'm wondering how long it took the DryLok to fail? Also, would be curious to know what the DryLok tech support line would recommend?

    Bookmark   June 14, 2006 at 9:57AM
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Boy, I'm definitely not a Dry-loc fan. It only stayed on where the walls are always dry. Everywhere else it crumbled off and created a huge mess. It is possible to paint over it, though, and the most successful paint I've used (because it doesn't discolor due to damp or existing stains) is Zinsser shellac based primer. It lasts for a good long time, stays nice and white and although it flakes off a bit where it becomes moist, it doesn't require anything but washing with a bleach solution before I put on another coat...usually every 5-8 years. I've been doing this for the past 20 years or so with the house we're in now.

    Bookmark   June 15, 2006 at 4:14PM
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Having worked in a paint department for several years back in college, I might be able to offer some advice. You are going to need to get a stiff wire brush to knock off all the loose paint from the walls. It's hard work but if not done, you are just going to paint over paint that is eventually going to peel off anyway taking the new paint with it.

Once you get the old loose paint off, clean the surface with a bleach and water solution (to kill ANY mildew or mold spores). Once that is completely dry, prime the wall with an oil based primer OR recoat with DryLoc. You cannot do both, one or the other.

Don't forget to keep good air circulation when using oil based paints.

Don't worry about using muriatic acid. It's more of a "last resort" for masonry that is too smooth for paint to adhere to like concrete floors.

Hope that helps.

    Bookmark   June 15, 2006 at 10:33PM
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We are in the process of finishing out a 1000 sq ft basement that also had horrible peeling yuck and efflorescence on the walls. We've had the wall problem licked for about 18 months now, and so far they look great. Our mess was related to years of previous lazy owners and the fact that the gutters were totally shot. So here's what we did: first ALL the peeling stuff has to come OFF. That's right, every bit. We even resorted to light use of a grinder, but be careful that you don't damage the block doing that. Anything left up there that has obviously failed will just flake off later, ruining your whole effort. Next, we washed it down one wall at a time with the Dry-lok brand etch powder. It was easier and seemed safer than muriatic acid, and actually turned out to be really easy, follow directions for neutralizing it. The advice we were given was that bleach doesn't do much for effloresence because the pH is all wrong - you need an acid. Next, the actual Dry-lok. Use a lot, use many coats, DO buy the special brushes they sell. We put up several good coats, with each brushful swirled and rubbed INTO the now clean and etched block. That part is key - it has to really BOND to the block, so just swiping it across the top of a porous surface won't work. So far it looks really good. Timing seems to be of the essence here as well - if you clean etch the block and then wait too long to apply the actual paint, you give it time to build up new mineral deposits. We are not planning to put up sheetrock or paneling, so we've just painted over the Dry-Lok with lots of textured paint and I have to say that I'm impressed. I realize that very few people that I've seen on this board are fans of this method, but it has really worked well for us. I certainly don't think that it would solve even a mild problem with actual leaking or water coming through the walls - but when you've taken the other steps to solve moisture problems it really can be a good way to stop effloresence and give you a nicer wall.

    Bookmark   June 17, 2006 at 8:00AM
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Rent a pressure washer. It should be able to get everything off quickly.
They do not use as much water as you think.
Dry the space out.

    Bookmark   June 17, 2006 at 1:10PM
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Loretta NJ Z6

What worries me about using a power washer indoors is that the mold will grow back before the basement dries out.

    Bookmark   June 19, 2006 at 1:05AM
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Use some detergent or bleach in the pressure washer, then shop shop vac the floor when you are done.
A few fans and open doors and it should dry within a few hours.

    Bookmark   June 20, 2006 at 9:15PM
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if you are going to go the pressure washer route....why not just sandblast the Drylok....same amount of mess but won't have to dry out or worry about mold and will more likely get drylok out of every nook and cranny for proper adhesion...just ALOT of brooming up the sand???

    Bookmark   September 7, 2007 at 3:33PM
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i tried citristrip to remove old paint off masonry, but it is not worth the trouble. Once you go to scrape off the paint, it gets jammed back into the pores of the cinder block. You could follow it up with a toothbrush to really get in the nooks and crannies but it would take FOREVER. And still it won't be perfect.

    Bookmark   September 24, 2007 at 2:07PM
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I, too, have the SAME issues as the original post. We purchased a house in Grosse Pointe Farms, MI, that was banked owned and sat empty and wet for one year. It had mold, efflorescence, and all the wood studs in the basement had rotted completely out. I have removed all the little rooms that a previous owner had built in the basement so now the house doesn't smell like a rotting cottage. I also just recently treated the walls to a nice bath with muriatic acid and water. The ironic thing about doing this process is that to rinse the wall after the acid application, you are putting moisture into the wall, and while it is all drying out with use of copious fans and dehumidifiers, you are actually pullout out more whispers of efflorescence! I just go down and scrape them off periodically while the basement dries out. We have also built up the sides of the house, scraped the old cracking paint off the basement walls, etc. I am now thinking I should lightly grind the walls to clean it of any leftover crystals and paint, then dryloc the walls. If I am just trying to keep the moisture from causing efflorescence, then this is the way to go. Forget the bleach, it does nothing for efflorescence. Forget the power washing, it puts too much moisture in the walls/air. Go with a dryloc type product or some other sealant to contain the moisture inside of the cinder block wall. If you have water leaking in from something else, then you have a bigger problem than just the efflorescence! Good luck!

    Bookmark   May 11, 2011 at 2:59PM
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My basement is dry, no moisture and the floor was painted with drylok (grey) laytex floor paint. I wanted to change the color, do I need to etch the floor or can I just paint over it almost like a third coat?

Any Advise would help. Thank You

    Bookmark   June 24, 2011 at 8:44AM
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My basement gets sum moisture not to bad when the lake by my home crests once a year it could get flooded im lookin at how a can coat my basement properly when that occurs ? ??? And what r the basic tools needed to get the job done myself ....

    Bookmark   July 7, 2011 at 10:45PM
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