Do concrete paints (drylock) actually work?

tom_p_paNovember 19, 2005

Do the concrete paints such as Drylock actually work? I have a below grade garage with 2 walls made of concrete block. Because it is below grade, I often get dampness on the walls creating mildew in the garage. My walls have never been painted. I know the proper way to control water is to do it from the exterior (excavatation, drains, sealing, etc), but the condition is so minor, I was wondering if the paint would work. Would it also make it feel drier and kind of keep moisture from coming through the earth to the block?

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Yes, they do. But I'd never use them. And I'd never buy a home that had Drylok on a wall. They DESTROY walls. They trap the moisture within the concrete and lead to early degredation.

Drylok should be, in my opinion, taken off the market.

    Bookmark   November 19, 2005 at 10:19PM
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They work. We had a hairline crack in the basement foundation wall, which used to exude some seepage. and I used it, and never saw leakage there again.

    Bookmark   November 20, 2005 at 1:29AM
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Why do Consumers Reports say Drylock is good and rate it as the best concrete block paint? It has been around for ages...if it was so bad, wouldn't it be pulled from the market by now?

    Bookmark   November 27, 2005 at 9:43PM
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I am sure Drylock will help keep down the dampness and be an overall improvement to your situation. I never heard of it damaging the walls though? I would think with any paint treatment, if enough water is behind the block, it will work its way out regardless, and blister the paint off. How much water can it actually hold back?

In the USA, everyone finds a need to finish basements. Actually, basements are the worst places to finish and should be left unfinished in my opinion.

Many basements are finished by homeowners who have no clue what they are doing. Basements can harbor unhealthy mold and mildew if finished incorrectly.

    Bookmark   November 28, 2005 at 7:25AM
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Does anyone know how these paints actually work...and what they are made of? Are they just a very thin cement mix than fills the pores in the block?

    Bookmark   November 29, 2005 at 7:19AM
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Wouldn't water coming through the block actually draw out the minerals from the concrete reducing its strength? I also heard dehumidifiers ruin walls too for the same reason. They draw moisture through the blocks removing the minerals from the concrete.

    Bookmark   November 30, 2005 at 6:07PM
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Well - See pictures below? That was when I bought the house. After fixing the grade outside & DryLocking the walls, I swear it is Bone Dry down there. We had downpours for hours, rain for 3 days straight, I GOT NOTHING! Truely amazed I added a 2nd coat.

The water was seeping through the concrete not coming from floor.

I had a quote of $7000 to fix the problem. I did it for $90. Screw those basement waterproofers! They are a scam.

& P.S - Cinder Blocks have cavities so water can build up "inside" the blocks as opposed of having pressure on them from the outside.

    Bookmark   December 6, 2007 at 6:21PM
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I had the same kind of leak thru the wall and would build up to an inch deep. Regraded the outside, did NOT drylock and its been dry for over 6 months.

chrisphillipi; you shouldn't join, resurrect an old thread, and try to peddle your wares. Not nice.

    Bookmark   December 7, 2007 at 12:23AM
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I heard drylock will buy you one year, I've used it as a patch but not to paint the wall, best to check the landscaping around the house, I've been fighting the water in the basement for a couple years, it heads toward the floor drain so I live with it. I think you can fix the cracks but find it pretty hard to stop the moisture vapor

    Bookmark   December 7, 2007 at 7:48PM
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Drylock is resin in a solvent.
The older stuff was acrylic resin in a petroleum solvent, the newer stuff is water based.
It can stop minor movement of vapor, but is not as effective against large amounts of liquid.

It is also good for preventing dusting of masonry surfaces.

    Bookmark   December 8, 2007 at 10:43AM
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If Drylock is not very good for block walls,
how is XYPEX concrete waterproofing
This company is in Canada and I have read good things about their product.

    Bookmark   March 19, 2009 at 5:51PM
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Chris implies that "15-18 gallons of water vapor per day." seep through my walls and only his system can stop it. ?!?

I don't buy that, unless he is calling these gallons of "vapor" as opposed to gallons of "liquid water". If all the water is coming through my walls, why don't I need to run my dehumidifier in the spring when there is a lot of water in the soil? I only need to run it when the air humidity levels get high in summer months.

The answer to this previous questions is that in most cases, most of the water vapor comes from outside air, not through the wall. The dampness on the walls that shows up in mid summer is condensation from inside air, not water seeping through. And the little that does come through does not amount to much at all, unless there are leaks or cracks or excessive hydrostatic pressure which will eventually force water through. The BEST solution to moisture or water coming through the wall is to divert the water away from the foundation by drainage, sump pumps, gutters, and landscaping. The next best solution is to patch up the cracks as good as possible and install some sort of interior drainage system if needed - but that is a poor second choice.

Sometimes, a wheelbarrow, a shovel, and some elbow grease to do a little landscaping to raise the grade near the house (keeping water draining away) is all that is needed. I just fixed one of our problem areas that way last summer.

    Bookmark   March 20, 2009 at 8:41AM
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Many houses from the 60's on, have their below surface areas parged with tar or other waterproofing and some even wrapped in plastic. Unless there are cracks or extremely poor outside grading or downspout placement, vapor migration from outside is practically zero. New construction will have many gallons of water in the concrete and block walls required for the mixing and processing of them. It can take up to 3 years to totally remove that excessive moisture depending on the processes used to remove the moisture from the structure.

Many of the waterproofing products use various methods for applying their waterproofing solutions which are in essence paint. Any good waterproofing will contain hydraulic cement and most likely not painted on per se.

Hydraulic cement is a powdered limestone that has been heated to higher temperatures than general purpose cement and it is very dry. It gains it's strength by being confined. If you put it into a hole or crack, as it cures, it also expands and becomes very strong. If you were to smear it onto a wall without cracks or fizures, it will dry hard and in a few years, it will start to powder off the surface except those areas where pressure has been experienced through swelling into a crack or hole. You can mix hydraulic cement into a ball, submerse it in water and plug a hole and within about 3 minutes will swell,cure, and plug the hole even if water had been agressivly flowing through it.

You can buy hydraulic cement at any home supply or hardware store. When you mix it, mix only the amount you will use in 3 minutes. It cures similar to how an epoxy will cure (although it is not an epoxy, it is limestone)in that it hardens at the same rate all the way through.It gets very hot as it is curing and can burn your skin if not careful. If you use warm or hot water, it will cure much faster. I would suggest only mixing (using cold water) an amount you will use in 2 minutes. Obviously this is a time consuming process and as you work it into pores of cinder block and cracks, you need to smooth the excess off to make it look nice, after assuring it has been forced into pores and cracks.

Once allowed to dry, the areas treated will have strong and permanent waterproofing properties. Then paint can be applied if desired. Unfortunatly, if there is a major water problem outside (especially where hydrostatic pressure can build) the repaired area, water will eventually seek a source which will allow it to come in. However, water vapor will not be an issue.

It appears it will come in and migrate to areas where you have expensive items stored or as any mechanic or handyman will tell you, where metal is stored and can rust.

    Bookmark   March 20, 2009 at 4:05PM
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drylock, sanitred, etc. Do Not Work, They are a temporary problem solving paint. they are good for small cracks. The only product that is actually Proven and Tested to WaterProof is "Armor Guard", ArmorGuard is certified green, odorless and non toxic. its a coating, NOT PAINT. its used to coat seawalls, aquariums, and dams, its an industrial coating. look on for more information.

    Bookmark   June 8, 2009 at 11:05AM
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Thank you to everyone who posted here. But I have a bigger problem and wonder if there are any suggestions or solutions. Approximately 10 years ago, we drylocked 1/2 or our basement. Only the side that we were using at the time. We couldn't afford to finish the basement and wanted it to be more presentable, so we were just going to paint it. But after a trip to Home Depot and talking with their friendly helper, he convinced us to use drylock. It was white, which was more presentable and it would seal the basement which would keep it dry. So, being the trusting people we were, we bought it and applied it. It worked well for about a year. Then imagine our surprise when we found mold! And not just a little mold, but mold on every box, every toy, walls, furniture. To the tune of thousands of dollars of cleanup, plastic boxes, ruined furniture, ruined clothing, medical bills, headaches. . . and so on. After the extensive cleanup (which we consulted with a mold expert on), it came back 3 times! This is exhausting. I'm at my wits end with this. Any ideas? Thanks!!

    Bookmark   June 26, 2010 at 11:17AM
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The information from the Owens Corning guy is ridiculous. He's just a salesman.

If you want to know what will waterproof a below grade block wall look at what is specified for the repair of elevator pits: chemical grout injection and/or hydraulic cement.

    Bookmark   June 26, 2010 at 12:37PM
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Install two large dehumidifiers connected to waste lines. Set them so they cycle off from time to time. Location is not important. Be prepared to replace them every few years.

    Bookmark   June 26, 2010 at 1:13PM
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The only long term solution to fix water/moisture from getting into a basement through the walls is to prevent the water/moisture from the OUTSIDE. That means digging away all the dirt around the basement and applying water proofing materials. Doing that to a specific area that leaks can work.

There is another problem that can cause water in basements. Water UNDER the floor. From a spring or from the water table. The only solution I have found for that problem is done by removing the floor along the walls, adding a water catching/channeling system with sump pumps, replacing the concrete(while leaving a narrow gap all along the walls), gluing heavy duty plastic to the walls(the gluing is done in strips with a special glue) and then finishing the walls by adding 2x4 walls installed about an inch inside the narrow strips.

I worked on three houses where there had been several attempts to use Drylok or other inside fixes. None of the solutions(including using dehumidifiers) worked. None of the three.

The only cures that solved the problem were as I described above. I have no connection with any other company, I do not own any stock, much less in any repair company, and often disbelieve most advertising.

But, the one company in all three cases I mentioned was Dry Basement in Kansas City, Missouri. They came on time, did the work in the time specified(less than two days) and the water/moisture problems in all three houses disappeared.

The three basements were completely finished(sheetrock, wood trim, paneling, etc.) and after 5 to nine years there has been no water/moisture problems.

Is it expensive? Sure. One house cost $7,000. Can you spend that much or more over time. I'd venture to say yes.

    Bookmark   June 26, 2010 at 6:50PM
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ABSOLUTELY NOT!!! And it SHOULD be taken off the market. First of all, the paint gets brittle and will chip off in patches within a few years, so it does no good. Secondly, it compresses moisture inside of the block and erodes it. More than once I have seen pieces of foundation wall come off at a light touch because water was stuck in the wall.

    Bookmark   March 7, 2011 at 12:26PM
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I have a home built in about 1929. all four basement walls are below grade and composed of glazed ceramic block. The house sits on a slope, the back wall being the uphill side and leaking the most. My landscaping angles away from the house so i don't think that's the issue. There are some small cracks in the morter that squirt in water but no cracks to be seen in the ceramic blocks. The basement was painted at one time but the paint is flaking off the glazed surfaces. The floor is unfinished concrete but the edges and corners are lower that the middle so water puddles in the corner. I was thinking of repairing the cracks and drylocking the walls but idk if that would work based on some research iv done.
Will it just peel off as this old paint has already began to do?
Will it stick to the glazed surfaces?
Will i have to pressure wash/wire wheel off ALL the existing paint?
If drylock wont work what are my options other than digging around the foundation and water proofing externally, internal trenches and sump pumps?
Perhaps if i just repaired the morter with cement that would sure my issues?

any help would be great.

    Bookmark   June 28, 2011 at 1:08PM
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I too have a tuck under concrete block wall garage like Tom P PA (2005). I also have a slight dampness in two spots. Reading that Drylok or paints of this type seem to not be preferable, is there a stain that would allow for vapor/moisture transfer and yet have some color enhancement for the walls?

    Bookmark   September 10, 2011 at 2:10PM
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"Secondly, it compresses moisture inside of the block and erodes it. More than once I have seen pieces of foundation wall come off at a light touch because water was stuck in the wall."

There was a lot of other problems if water damaged a concrete or block wall.

Those materials are considered waterproof, to the extent water does not harm them.

Freezing of water saturated walls is a different matter.
blocks are more probe to significant damage, but even concrete can have spalling problems if it is saturated with water and then freezes.

    Bookmark   September 10, 2011 at 3:17PM
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I would recomend a waterproof cement and then a painting we call it "tanking" in the UK

    Bookmark   September 17, 2011 at 12:00AM
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I have seen many a dryloked basement where the drylok was peeling and a black mold was growing behind it or showing through as a dark stain usually towards the bottom of the wall. My applications on basement walls and floors is always with Hydroseal 75. This is a waterbase epoxy that is mixed 1 to 1 prior to paint on application. One great feature is it is odorless and another is it is applied with paint rollers and brushes.

I always paint out a rollers lenght on the floor and if there is a gap where the floor meets the wall I mix concrete sand mix into the Hydroseal 75 and make a mortar that I can force into the gap or joint with the back of a spoon. Then two coats over the entire area I am coating does the trick. 1 day to apply 2 coats and patching , all with one product. I have not found anything better and easier to apply or anything that stops water better. This is easy epoxy to work with, has no smell, comes with an anti microbial added so it will not support mold growth and is sold in singles gallons or pails so you can buy as little as you like or do a test area with a gallon. I use the gray almost always but it is available in white as well. The white can be pigmented with universal tint.

I have also mixed it with hydraulic cement in very wet situations where the concrete was to wet to let the Hydroseal dry, and I have sprayed the Hydroseal 75 through an airless spayer to do a stone foundation over 100 years old. Mostly though I roll it and patch with it.

this stuff works great and there is a need for this type of product. Not all coatings peel off; like the guy said above, you need a coating that is used in elevator pits that can stand high amounts of pressure like Hydroseal 75

    Bookmark   September 28, 2011 at 3:06PM
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I would recommend hydro seal or any of the other products made by the Thoro company as they are all high quality products

    Bookmark   September 29, 2011 at 11:01AM
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One of the reasons concrete waterproofing paints flake off is because the wall had efflorescence on it prior to painting. The moisture coming through the wall carries salts and other chemical compounds to the surface of the wall. It often dries as a white powder. It should be completely rinsed from the wall prior to painting. Special efflorescence cleaners which are available at hardware / big box stores usually contain some form of acid. Muriatic acid diluted 1:12 with water can also be used, but produces fumes which can be toxic (so ventilate the area with fresh air). Saturate the wall prior to using acid products, because you only want the acid on the surface rather than soaking into the wall. Acid soaking into the wall will deteriorate the wall. Sponge the wall with fresh drinkable water to remove the excess acid and the efflorescent chemicals. Only then are you ready to paint the waterproofing coating onto the wall.

The link below from the Masonry Institute website discusses efflorescence, with information for removal at the end of the article.

Here is a link that might be useful:

    Bookmark   July 5, 2013 at 12:45PM
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