Painting Block Basement Wall


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Old 11-13-14, 07:55 AM
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Painting Block Basement Wall

I know I'm beating a dead horse here but I still have concerns about doing this. The plan is to paint one block wall in my basement using drylok and then paint over that with normal interior latex paint.

Every once in a while the block appears damp. I am currently doing the "Foil Test" to determine if it is seepage or condensation or both. I have never had a standing water issue in the basement in the 3 years of living here. I do not believe my house is below the water table as the neighborhood is set on a large slope and we are towards the top of the hill. There are some evanescence deposits on the wall. I've already prepped the wall by brushing with a wire brush, using the drylok etch and patching a crack towards the top of the wall and some smaller cracks in the mortar joints here and there.

Concerns I have: I read some where else, I believe written by someone slinging there own expensive waterproofing products, that drylok type products can contribute to a mold problem. Is this true? I also read that, again some where else, drylok is bad for the cinder block, that it will cause damage to the block? I've also read where people have had drylok chip away from the wall.

Does anyone have experience with this product? Recommend or no? Are the problems people having with it because they did not do the proper prep work?

Again, I'm sorry for beating a dead horse but I need to put my mind at ease.

The pictures are shortly after rinsing off the drylok etch, that's why it looks wet. The second picture is right of the window where I patched a larger crack to the top and shows the discoloration in brick, I believe to be caused by that crack and not simple seepage. The pictures probably don't help much due to my having just rinsed the wall off huh?
 
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Old 11-13-14, 09:08 AM
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I've applied a lot of drylok over the years and it's one of the better primers for below grade block BUT water issues should always be addressed on the outside! About the only time drylok will cause issues is when it's used to stop significant amount of water from migrating thru the block. If water backs up in the core of the block it can cause damage over time. Effervescence is caused by moisture going thru masonry.
 
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Old 11-13-14, 09:37 AM
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I agree with Mark, trying to manage the moisture issues from inside will rarely solve the problems.
"I do not believe my house is below the water table" but it is below the moisture table. When you attempt to seal out water with drylock it does not block moisture vapor, Drylok is designed to be vapor permeable. So however moist the soil is outside the foundation is moisture that will be passing through those walls.

The efflorescence you describe is the mineral deposit left behind from moisture passing through, so yes you have a moisture problem and no the drylock and your efforts on the inside will not resolve it.

Blocks have an additional problem in that they have hollow cores so whatever water enters anywhere it can flow around the foundation until it soaks through.

Between the moisture vapor and the liquid water issues, avoid any vapor barrier on the inside and use a good dehumidifier. More, if the bad news isn't hurting too much.

Bud
 
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Old 11-13-14, 11:56 AM
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I feel a little dumb.

Bud and Mark, I really appreciate your quick responses. I guess I'm still having a problem understanding. The idea of using drylok waterproofer is simply for aesthetic purposes. To use as a primer for another coat of paint. I understand the basic principal of solving water issues from the outside, but I'm still a little confused.
Mark wrote, "About the only time drylok will cause issues is when it's used to stop significant amount of water from migrating thru the block."

I do not feel that I have a significant water problem, unless my blocks being occasionally damp is in fact a significant water problem. I'm not really concerned with the little moisture I do get. I do always run a dehumidifier down there to protect my hunting equipment however. The drylok will still allow moisture to pass through, therefore water shouldn't back up and cause damage. Right? Would adding a coat of normal interior latex paint on top be a bad idea then? I'm sorry if I'm being redundant.

Also, I should have put this in the original post, the house is 12 years old, there is a pit with a sump pump that only seems to have water in it and run during heavy rain periods.
 
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Old 11-13-14, 12:59 PM
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I think you're fine - we get a lot of people posting questions about using Drylok to 'fix' a water problem so we've become a little sensitized.
 
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Old 11-13-14, 01:56 PM
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To paint block, you need to use a special primer; above grade we use block fill but below grade we use drylok. Latex wall paint over the drylok is fine. I've always felt confident applying drylok to dry or occasionally damp block foundation walls. While I have applied drylok to wet basement walls in an attempt to keep them dry [per customer's/builder's request] I know it's not right and will not warrant those jobs!
 
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Old 11-13-14, 02:35 PM
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I prefer to use Thoroseal since I am familiar and used/specified on repairs from dams to architectural features on buildings.

It is not easy or simple but does a great job. It must be applied to a wall that is damp or misted. The mixing of the powder must be done as specified, including a wait of a few minutes to let it "fatten up" (like thick pancake batter).

You can get a good coat and any additional coats must be applied to a misted wall 24 hours later to get a good surface that can mask mortar joints. Any longer, you must use an adhesive/latex additive.

It started as a commercial/industrial product years ago and is not really promoted as "waterproofer".

I used it on my own basement that had severe moisture problems (75' long house/garage the intercepted the natural drainage and groundwater) after it worked so well, I punched a hole in the second course of block and got a stream that went out a couple of feet to remove the accumulated water. After that, I used it on the rest of the basement walls plus I put pvc tubes from the cores into the interior drain tile when I finished the basement.


It is definitely not a "paint"-type product, but is cementitious, just like concrete and becomes part of the wall.

Dick
 
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Old 11-13-14, 02:46 PM
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@ Woodstock "The drylok will still allow moisture to pass through, therefore water shouldn't back up and cause damage. Right?" No.
The amount of moisture vapor that will pass through the block with Drylock on it will not lower the water level in any reasonable time. Picking up a humidity gauge and running a dehumidifier will keep you on top of future moisture issues. The real concern would be if you decide to cover everything up with finished walls, then any moisture vapor that sneaks through only becomes noticeable after it has become a problem.

To keep me from going back and reading, are you going to finish those walls or is the paint going to be the final layer?

In either case, the house to foundation gap needs to be air sealed and the rim joist area well insulated. In addition, above grade areas or the foundation should have some form of insulation. One inch of rigid doesn't sound like a lot, but those block walls are only about r=1 or 2 in total.

Bud
 
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Old 11-13-14, 04:35 PM
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Bud, the paint on the block is going to be the finish. I am not going to drywall. Just trying to make the dungeon a little nicer. Also, could I just set out the hygrometer from my humidor to get an idea of the humidity down there? Also, what really does that tell me other than the humidity level? If it's high for example, what does that mean? Just curious.

My girlfriend wants to do something like this in the picture.
 
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Old 11-13-14, 05:34 PM
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The relative humidity reading will vary depending upon temperature. As the temp drops, like getting closer to a cold wall, the rh increases. The amount of moisture in the air is the same, but rh is a measure of how close to capacity the air is. Warmer and it can hold more so reads a lower number. Colder it is getting close to capacity so reads a higher number. Eventually, as the air gets even colder the rh reaches 100% and moisture will begin to form on the colder surfaces. To prevent the condensation you would need to reduce the moisture in the air or raise the temperature.

But there is another issue, mold. Long before you reach the 100% level, the mold spores in the air and on everything will have sufficient humidity to begin growing. Keeping the rh below 50% is a good measure to keep the mold from growing and that 50% needs to be measure in the cooler areas. There is some wiggle room with that number, but you just don't want to be seeing 60, 70, or 80% numbers. In your case, when you see the condensation you are reaching 100%.

The hygrometer from your humidor is fine to get an idea. But a meter with both temp and rh is a handy tool to have.

Bud
 
 

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