I know what you are thinking… what do you mean, do not paint your walls in your basement?!
I am not talking about finished walls like drywall. I am talking about do not paint your foundation walls like concrete, brick, and block.
Remember, most foundation walls allow moisture and humidity into your basement. Many paints are not strong enough to hold back the hydrostatic pressure. Even if they are able to stop the hydrostatic pressure, paint is mold food!
In the picture above the homeowner painted their basement wall. The paint did not reach the footer. Water still enters the basement at the cove.
The foundation repair specialists from Crawl Space Ninja had to do interior waterproofing system for this homeowner because the paint did not hold back the moisture intrusion due to hydrostatic pressure.
What is Hyrdrostatic Pressure
Hydrostatic pressure is the “force that pulls water into dry spaces. Think of dry ground as a sponge, and standing water around your foundation can seep its way under or through the brick foundation through this hydrostatic pressure. The dry space, along with the weight of the water, pulls the moisture into the “void” space in the bricks.
Over time, the water works through the brick to the other side and accumulates, creating the dank moisture you feel in a crawl space or basement.
Poorly Painted Basement Walls Do Not Hold Back Water
You may have seen that display in the home improvement store with a block covered in waterproof paint. A lot of homeowners get idea that waterproof paint will fix a waterproofing problem in their basement.
This is a mistake made by many DIYers and basement waterproofing contractors. Waterproofing paint is rarely, if ever installed correctly. If it is not installed correctly, it voids the warranty and effectiveness.
Never Repaint the Basement Wall
Installing new waterproofing paint over old waterproof paint will void the warranty. It is right there on their install instructions. Chances are most homeowners are unaware that reapplying paint to basement walls, voids warranty. If the paint worked so well, why would you need to reapply?
The fact the the warranty is voided during reapplication should tell you they don’t believe in their product.
Straight from the can of waterproofing paint:
“Surface must be clean and free from dirt,
dust, grease, oil, form release compound, or
paint.”
Concrete Does Not Support Mold Growth
Even if your basement wall is flooding it cannot support mold growth.
Why add mold food to your wall?!
Have you ever tried to remove waterproof paint? You have to grind it off, trust me it is not easy and very messy. You are better off avoiding waterproof paint from the start
Antimicrobials in Paints Fail Under Prime Conditions
According to many experts, paints with antimicrobial additives will eventually grow mold if the conditions are right. Imagine you paint the basement wall and then decide to build a finished wall over it. The waterproof paint is the food. The hydrostatic pressure supplies the water.
You just created a dark, damp mold food rich environment.
Most homeowners are just unaware about the details of good air quality and foundation health. Here are some great resources to help you eliminate moisture in your home!
Articles About Basement Waterproofing:
Contact Crawl Space Ninja for Basement Waterproofing
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34 thoughts on “Basement Finishing: Do Not Paint Your Walls”
Another good piece of information I found on buildingscience.com about not painting walls, is cinderblock is engineered To be pores and allow moisture to travel through be cause hollow block is not designed to hold back the force caused by hydrostatic pressure build up that happens when you paint cinder block. Painting the walls drastically increases the chance for cinderblock walls bow. The article I read said you should not even tar the outside of cinder block walls unless atleast every 3rd cell was poured with concrete to support the extra hydrostatic pressure.
I have newly installed concrete walls over a vapor barrier in my basement. Since the vapor barrier is installed, can I paint over the raw concrete? If so, is there a product you would recommend?
Hi Deb, I never paint interior concrete walls. I am sure some contractors are ok with it. In my opinion, there are too many things that can create a moisture problem and cause the paint to eventually grow mold. Once that happens, removing the paint is very difficult and extremely messy. I like a vapor barrier on walls vs a paint. Hope that helps.
i have a inside wall that is painted and bubbling off the concrete with lots of black mold. i have been scraping it, but there is some paint that wont come off. i was going to paint it with basement paint.
what do you think i should do?
Grinding is the best way and the most difficult to do. If your scraping method is working great, remove as much as you can. We don’t paint foundation walls. Paint can be a mold food source. Check with local basement waterproofing company that may use vapor barriers on the walls. Hope that helps.
Is there a mineral or lime wash paint you can recommend? Thank you
Hi Joy, I am sorry I don’t have a recommendation for that.
@ Michael Church:
When you say “grind” what type of method do you use?
I’m in the middle of a basement rehab. The block walls appear to have 3 coats of paint and were hidden behind 1970s paneling (no vapor barrier, no insulation, just 1×2 framing nailed into block joints). The lady who lived here before us never cleaned her gutters and in on corner, after tearing out the paneling, I discovered badly bubbled/peeled paint and black mold galore. To kill the mold, for a week I sprayed vinegar on that area every other day and pointed a dehumidifier at it in between. Then I began grinding with a diamond 5” disk with a handheld grinder. It works… some what.
Man, the paint seems to be like iron skin. The peeling stuff came off ok, but as I moved further away it got nearly impossible to get down to the concrete. I’ve got about 3 or 4 feet out each side from that corner ground and one disk is already spent. And with the disk you really can’t get into the joints, so I thought I’d try a wire wheel. All that did was make black marks on the paint. And holding that grinder… my arms are gonna look like Popeye’s or they’re gonna fall off!
Any suggestions much appreciated.
Mike, it sounds like you are doing exactly what we would have done in the past, until we did the one job and decided we would never do it again. The diamond disk seems to be the best option but as you stated it is almost impossible. It is unfortunate there are so many painted basement and crawl space foundation walls out there that cannot be fixed correctly due to not having a good option to removing the paint. Even the $2000 Hilti grinder says it removes paint from concrete and block and I am sure it does but I feel the Popeye arms are a necessary side effect. I am sorry I don’t have a better solution for you which is why I have been trying to educate homeowners not to paint their basement walls.
Thanks for the reply. I’m with you on the do-not-paint-concrete. It never made sense to me. All it does is lock the wet inside. Concrete needs to breathe.
Guess I’ll stock up on spinach.
Do you have the same concern with painting unfinished basement floors?
Hi Meg, I do have concerns if the paint used can become a food source for mold and the concrete floor has high levels of trapped moisture like many older built homes may have in our area. Today floors have a gravel bed and even plastic installed prior to concrete being installed. Older homes don’t always have that so they can wick water directly from the soil. Hope that helps. Thank you
My dad had a leak in a bathroom upstairs which resulted in his basement being flooded. The paneled walls and doors are now covered in mold. His insurance is paying for professionals to come in and remove the mold which also means removing all the paneling. I had considered just painting the concrete walls until I read this article. What do you suggest we put on the walls for a finished look that is also resistant to mold and economical? I would rather not put paneling back up.
Carla, some of the decorative waterproof panels that can be used on basement walls are amazing. I am not endorsing any brand or type but here is one and there are many others to choose from. Looks like a pretty straight forward DIY product. https://amzn.to/3dEONF4 Hope that helps.
I have finished several basements. as a non professional and advise not painting the walls also but use plastic on the stud built wall facing the concrete. Allow a one inch clearance between the concrete wall and stud wall. The stud wall should be supported by the above floor joists and allow a 1/2″ to 3/4″ space between the bottom treated plate and wall floor joist. You drill clearance holes in the bottom wall plate and then nail through the clearance holes to the bottom wall joist to the treated.lumber. This way of construction allows the basement cement floor to heave if necessary without compromising the structural integrity of the home above. The 1″ space between the plastic and basement cement walls allows air to flow and prevent dampness build up. If you have long basement walls a psuedo cold air return vent at the bottom of the plate floor will allow a positive air flow between the plastic and wall. If you fiberglass insulate the walls make sure the puedo cold air return passes through and beyond the plastic. Yes you will lose some r factor but gain the peace of mind that no mold will grow on the plastic construction dust. I also use drywall meant for basements to inhibit mold. This I believe is the best way to finish a basement. Remember to get building permits. The inspectors are there to protect you and will suggest corrections if necessary.
Hi! i am now convinced not to paint the ugly cinder block in my crawlspace. However, there is a basement room next to the crawl which has full windows above ground(since the house is on a slope, the crawl is up the hill and has less of it above ground.)This basement room has all cinderblock which has 60 year old paneling which is attached to furring strips and nailed in. There is no insulation or water proofing material between this old paneling and the cinder block. I wonder if the plastic panels u mentioned could be attached to the furring strips. thnks. although i dont see mold, i do want this room to have a good smell and have healthy air.(by the way, the vented, windowed crawl is not dirt- it is a huge boulder! thnx again.
Hi Bonnie, Most plastic panels can be attached directly to the block or concrete. You can probably attach to fir strips but they are pretty flimsy and may bow or sink between the strips if there is a lot of space between them. Hope that helps.
Would I have the above said issues if my house is about 15 years old and we have no moisture issues in our basement? I want to paint the walls to stop the dust and I did have a thought about doing the floor in Kills.
Hi Frankie, great question. It is possible for your basement walls to take on moisture in the future and still create an issue with painted walls. I have spoken with homeowners that painted the walls with waterproof paint to make the area look good not because of moisture. Eventually, in those cases, the water punched through the paint and created a mold issue. Hope that helps.
We bought a 150 year old cream city brick house a few years ago. The basement foundation seems to be limestone rocks with some interior brick walls. There is a thick coating of white paint or something over the walls on the inside which is peeling off. My husband scraped some of it off and vacuumed everything and then built tables for a model railroad. We are wondering what to do to protect and care for the walls. I wish I could send you a picture.
Hi Karen, have you looked into an interior stucco? I am not recommending that because we don’t get involved in the interior basement wall fix except vapor barrier on walls. Just a thought I had after reading your comment. Hope that helps.
Hi Michael,
Thanks for the information you put out into the world!
I’m helping some friends out with a situation where there is existing paint on the basement walls. The hope is to cover the walls with a plastic vapor barrier and put in an interior drainage system. (much like a crawl space encapsulation)
The question I have is whether it’s a good idea to cover the paint with the plastic vapor barrier, or remove the paint before adding the plastic vapor barrier. What do you recommend?
I’m concerned the paint will grow mold if it’s covered.
Thank you!
Hi Ken, thank you. Yes covering the paint with plastic will allow the paint to continue to grow mold. Removing the paint is a nightmare but is the best option to address the mold covered paint prior to putting up plastic. In asbestos mitigation you are allowed to encapsulate the asbestos. Many times encapsulating asbestos is better than removing it. If you decide to encapsulate the moldy paint, make sure you do it permanently so it cannot make it’s way into your living space. This could be done with plastic and sealant but is extremely difficult to do effectively. Hope that helps.
Sadly, I painted my poured basement walls some 25 years ago. Luckily I did a mediocre job, so about 85% paint is still there, to be removed I suppose. I am wondering if I could just brush clean the walls, and install simple 1″ or 2″ thick styro insulation (stood off from the conc. 1″ with non wood standoffs) as both a temporary and quick clean up to one end of the basement about 10x10ft. I would tape the seams and simply call it good for storage.
This would reduce my needs for structural wall building to a single 10 ft of wall, legit with studs and drywall and door. Later I can erect actual walls around the other 3 sides, with an egress window, for permit. But for now just to separate that storage area with a door and create a clean space. I would also paint out the ceiling white in that area to create more light. thanks for your thoughts. Re the single door wall, I can affix it to the floor joists and basement floor for stability
as it is the only wall. (i have a small half basement, so its about 11×15 feet down there. I have drawn out the eventual habitable room but for now this would help me afford the insulation first.
best from oregon
I have unfinished poured concrete halfway up the walls in our exposed basement. It is in an unfinished laundry room and honestly I am just looking to make it a bit more attractive. Is there an inexpensive option, instead of paint, that would just “jazz up” boring poured concrete without being a mold issue?
Hi Laura, not sure what you are looking for but other than paints, here is an option. https://amzn.to/3kjVoHL
House built in 1991. No evidence of concrete leaking… EVER, says the öwner and his wife…I believe them.
I was contacted to paint, but before that, also seal the concrete with a Sherwin Williams concrete sealer to prevent moisture getting to the paint..
. At $75 / gal. The homeowners are telling me that it is good enough, when I’ve rolled on with a ¾” nap roller, and have taken and brushes almost all of the¼or better in size holes in the concrete(air pockets I presume?).
. But without going and getting another gallon of the pricy sealer…there are still a lot of littler holes that weren’t totally covered…
Well, I’ve sealed to the satisfaction, today. Tomorrow, I’m to paint that same sealed concrete wall with an interior latex based paint. This is my first time hearing about the types of problems that you say can and will eventually occur
…I wish I had seen these posts before so I could have advised against with alternatives.
Alternatively, the same homeowners have painted a different section of the same concrete wall years before, and I have looked closely at it—I didn’t see any issues with it… it looked as if it was just painted the year before… looked great in fact
…. ethically, I’m going to show them these posts, and then after, see if they want me to go on to paint any ways or maybe even seal ALL of the itsy bitsy little holes to completion….. this sucks!
Thanks Michael,
— bummed out (Wichita,Ks)
Ps : any recommendations would be helpful…I start at 8am tomorrow, well today it’s 12:15am 😔🤕
Hi James, so sorry you are having to deal with this issue. Just do you best to seal the holes. There are some way more pricy epoxy’s on the market that tout no mold and better seal. I don’t know how good they work because we don’t use them. But as you can imagine they are likely 3 to 5 times more expensive than brands at local hardware stores. Plus they still only have a 40 psi rating which does not seem that great to me. If hydrostatic pressure can shift walls, not sure how a paint can stop it. Hope that helps.
Could a white surface cement or quick wall be used on existing unpainted cement block wall without stopping the vapor movement provided by cement block? Also, do you know if surface cement/quick wall would encourage or sustain growth of mold?
Hi Chris, I apologize, I don’t have an answer for that. Could you send me information on the type of product you are using?
Hello,
I have an old house that has crumbling concrete (?) or maybe it’s stone? – a Brooklyn townhouse from 1901…
I am not interested in painting or even how it looks really, I just want the crumbling to stop. Is there a product I could spray or paint on that would sort of seal in the crumbling part?
Thank you!!
Research applying spray foam on the block or concrete. A lot of times spray foam may add structural stability. It may not look great when it’s done but it should keep it from getting worse. Also do a test are. Because once it goes on it’s hard get off if you don’t like it.
Would it be better to put in studs and add drywall to a concrete basement to finish it or use the stick on walls you’ve been linking? I’m thinking what’s better for breathing purposes of the wall.
As long as it is waterproofed, I like a wall that is built off the block/concrete vs sticking something to the block/concrete. More opportunity to insulate, run electrical/plumbing if needed. Hope that helps.