Let’s be clear about something – basement waterproofing paint, does not waterproof your basement.
Doesn't make sense does it?
Think of it like fix-a-flat for your car tires. Putting fix-a-flat in your tire doesn't FIX the real problem (the nail sticking out of it), it just mitigates a bigger problem until you can get the real cause fixed.
In the same way, if you have cracks or improper/insufficient drainage around your basement, using basement waterproofing paint isn’t going to fix that. Basement waterproofing usually requires a combination of solutions.
So why am I reading this? What benefit does basement waterproofing paint provide? And what is the best method to apply it? I’m glad you asked...
Basement Waterproofing Paint Benefits
Vapor Barrier – Most basement waterproofing paint products serve as an excellent vapor barrier. This is the primary benefit of waterproof paint. It will help prevent the diffusion of water into your basement.
If your basement is concrete, like mine, it’s very porous and even if all of your ducks are in a row as far as drainage, you can still see quite a bit of minor seepage during heavy rains without it.
Mold/Mildew resistance – Mold: The Joker to your Batman (The serious Heath Ledger type too, not the goofball Jack Nicholson kind).
By waterproofing, you prevent water from condensing between your drywall and concrete. The water has nowhere to go but to sit on your studs or insulation and form mold. No bueno.
Minor seepage prevention – Again, the paint will not prevent major seepage, but it should do a nice job of preventing the small amounts of seepage you will see through very small cracks and cement porosity.
In order to work as intended though you need to make sure paint adequately gets into these small areas, which leads me to my next point…
How to Apply Waterproof Paint
For my basement, I used Behr Premium Interior/Exterior Basement Waterproofing Paint. It is slightly thicker than standard paint, and it was a “bear” to apply (see what I did there?).
My initial plan was as follows: Use a paintbrush to “trim” around windows, the floor, ceiling, and corners, and then roll the rest just like you would paint a normal room.
Good idea right?
Well, phase one went well enough. A paintbrush did a good enough job of getting the paint into the tiny holes in the concrete. It took me a solid hour to trim the whole basement. Then I was on to the roller…
I used a standard 3/8’’ nap roller – you know the kind you use for drywall. This was terrible at getting into the holes in the concrete. Also, because of the paint thickness, it took me FOR-EV-ER to roll one small wall.
So almost another hour later, I had about 1/10 of my basement painted, and that 1/10 looked like swiss cheese with no paint in the holes. I gave up.
While complaining to a buddy at work the next day, I got thrown a lifeline. Shout out to my buddy Andrew, the proud owner of a Graco airless sprayer. He volunteered to help and he works cheap too – it only cost me a new spray tip and some Chicago deep dish pizza.
Because the paint is thicker, it requires a 0.023’’-0.025’’ tip. Standard paint typically uses 0.015’’-0.019’’ tips. We had the whole basement painted, and painted well, in under an hour.
I highly recommend having a friend with an airless sprayer. If that’s not an option for you, or they don’t work as cheaply as my friends, you have a couple options:
Rental – The D’Po rents airless sprayers. It’s certainly pricier than having a cheap friend, but may still be worth it rather than pulling your hair out rolling for hours. They offer 4 hour and day rentals.
I can’t imagine a basement that couldn't get done in under 4 hours the way those things cover. Take note of the available sprayer tips. If the tip is too small you risk clogging the gun.
Buy One - If you're friendless, or your lame friends don't have paint sprayers then pony up some cash for your own.
They're pricey but not outrageous. Plus, with the money you're saving by not hiring painters - you're actually making money. Check out the Amazon reviews for paint sprayers here. Airless Paint Sprayer Reviews
Rough Surface Roller – If you must use a roller, go with a heavy nap (3/4’’ or larger). This should help get paint into the small holes in the concrete. Don't skimp on paint either. Lay it on thick and use at least 2 coats, more if you have the spare paint.
Hope this helped you on your way to a drier basement. Questions? Leave them in the comments section below!
-Adam
(my profile picture and bio are coming soon... stay tuned)
Thinking about starting our basement soon. I've seen closed cell foam insulation used a lot of This Old House and other similar shows. I've also considered using a waterproofing paint and traditional (fiberglass) insulation as well. If I went with the close cell foam, would you suggest using the waterproofing paint as an extra measure or would that make the foam not adhere as well?
As an FYI - I haven't had any problems with water in the 5 years I've lived in my 1950's home and don't suspect it was an issue before I moved in. But you never know, right?
Thoughts??
- Jon
Jon - I plan to write another post about this exact topic (closed cell foam installation) in the near future, as I am currently applying it to my basement. Thus far I have had no issues applying it to my painted walls - they are adhering well. I don't want to spoil the punch line of that article, but make sure you use adequate adhesive (they make special adhesive for foam board which doesn't burn the foam) and make sure constant pressure is applied to the boards until curing of the adhesive occurs. I'll include pictures in that article. Until then, good luck!
-Adam
Jon W. I did exactly what you are describing. I put two layers of Drylok on my masonry walls prior to putting up 2" XPS foam board. Two things I'd recommend based on my experience. For the first coat use a brush for the whole area. Very time consuming, but it allows you to work the Drylok (or paint) into all of the micro cracks. The second layer you can use a roller. I also found that the XPS adheres to the wall easier with the Drylok then without it (I started a wall then went back and decided to use the Drylok). I've never had any water/moisture issues, but figured one more "layer" of protection couldn't hurt.
Thanks for the comment and sharing your experience. I have heard that overtime even Drylok has issues. I'm starting to the basement finishing project and my contractor recommended to use Drylok to minimize moisture issues down the road. Given basement will have moisture. Thoughts?
Have you heard anyone use the Radon sealant? It's just sprayed on using a pump spray and clear. We'll be covering it up with drywall anyway.
Ray - I can't say that I've heard of a radon sealant. Anybody else? - Jason
I used a coat of Clear Drylok. It's the only one of the Drylok products said to help with Radon. I followed that up with a coat of Extreme Drylok. Monitored my Radon levels and it went from roughly .80 to .40.
Cory - That's awesome and good to know you can remediate without installing a fan. Cheers, Jason
I am a painting (and drywall and carpentry) contractor and I did a search to see how other people or pros do this job. As a professional I obviously use the sprayer also. For DIYers - do research first so you know how to use an airless sprayer properly. They're not toys. Graco sprayers are as good as it gets. Proper technique examples: make sure your gun-hand is already moving before you pull the trigger; keep your wrist straight as you spray back and forth, etc. If you own the machine, make sure you really do a good job of cleaning it. My sprayer is fairly new but before I started my own business my old boss had sprayers that were over a decade old because he took such good care of them.
Again, really well-written and informative article. Well done sir.
- Richard D'Angelo, owner at CraftPro Contracting (www.craftprocontracting.com/blog)
Morristown, New Jersey
Thanks Richard - good tips! Go Morristown, my Grandmas is from Sparta New Jersey.
The previous owner added a great dining room onto the house to include pouring a full foundation underneath...eventually he punched a door into the main basement for access vs using a trap door. Where the new foundation walls connects to the old foundation there are some cracks. The walls are dry, I have done some chalking where the new foundation wall meets the old and I have added some additional back filling around the outside of the dining room. This seems to have solved the problem for now. Questions do I still need to paint the walls and any suggestions on additional filler for the joints?
Wondering what Model Graco sprayer you used for Dry Loc? It appears you would need a very large unit for the tip size you reccommend.
Try Cjspray.com for your sprayer needs. I just rehab'd our home after purchasing via short sale and needed a sprayer to spray over 100 gallons of interior paint. It worked flawlessly and CJspray tech support was excellent when I had questions. I never sprayed before and had a few questions....they were ready and willing to answer. These sprayers are refurb's, but still come with a warranty.
I want to sheet rock my basement. It's an 1930's house. The basement is damp but not really any water coming in. The walls have kilz on them and in spots has a rust color bleeding through. What should I use to seal my walls before I sheet rock. I do run a dehumidifier. Thanks. Charlie
Adam or Jason, I had a similar question to Chris earlier in the comments. Which model of Graco sprayer did you use for this project? I'm assuming it was the recommended Magnum X5? I think that Chris is asking because the tip-size chart from the Graco Airless Accessories PDF shows the beginning flow rate to be 0.57gpm for a tip size of 0.023", and that the spray pattern would only be 6 to 8 inches wide. The footnote on that chart says that this is just a baseline set by water @ 2000psi. A thick paint such as a waterproofer should bring that flow rate down MUCH further. So I can understand the Magnum X5 handling this paint with a 10 inch wide spray, which is about what width spray your buddy Andrew seems to be painting in the picture from the article. So one final question: which tip did you buy that dropped into the spray gun that came with the Magnum X5? (on Amazon the included gun is a Graco SG2)
I have a question about tips. Most of the sprayers I'm finding online (including the Graco Magnum X5) say the max tip size they support is .015", so which sprayers support a larger tip? Isn't that smaller than .023"? Am I mis-reading the specs?
Thanks
In regards to coating and patching cracks and holes in the basements interior I suggest Hydro-Seal 75 water based epoxy coating and Hydro Seal 75 Mortar. This material can be mixed with cement and sand (or concrete sand mix)instead of water to create a waterproof patching and filling material great for waterproof crack filling. To patch where the floor meets the wall the back of a spoon works best to force the mortar into the joint. Two coats of Hydro-Seal 75 applied to basement walls and floors will withstand over 40 PSI, It is available in White & gray and is a great choice for sealing basements from the negative side
My basement already has the stud walls on the exterior. I am interested in sealing them using this paint but I am wondering it you can use it with the walls on there. The studs are correctly places off the concrete (about a 1/2 inch) so I could completely seal the wall.
Thanks
I want to sheet rock my basement. It’s an 1930’s house. The basement is damp but not really any water coming in. The walls have kilz on them and in spots has a rust color bleeding through. What should I use to seal my walls before I sheet rock. I do run a dehumidifier. Thanks. Athena
Hi Athena - Well, KILZ is what I would recommend. It seems like you've got your bases covered. Maybe just another coat of Kilz. - Jason
Hey guys, my first post on the site. Want to give my experience waterproofing, since I just finished.
First off, Jason, great site/video’s/book…really helpful.
After reading this article I decided to get a sprayer for this job and some upcoming exterior house painting. I got the X5. To answer some questions above about the X5, the .015 tip that comes with the sprayer clogged almost instantly with the Behr waterproof paint. I ended up using the .021 tip (even though the X5 is not rated for it) and the sprayer worked fine.
I did try to roller one of the walls to see how difficult it would be, and Adam’s right, it would take a very long time to do this job with a roller and would have required some brushing to get paint in the concrete pits. So from my perspective the only way to do this is with a sprayer.
This job from set-up to clean-up took me just over 5 hours (including a 30 min run the HD for more paint) to do 800 sqft 2 coats, so Adam’s friend must have been a lot more efficient than me! I will say, this was my 1st time using a sprayer and the learning curve took a lot longer than I anticipated. I ended up spraying a moderately heavy 1st coat to try and get in the concrete pits and rollered over each section before spraying the next. The 2nd coat was lighter quicker spray only coat. But there was a lot of trial and error before I figured out what worked for me. All in all, it wasn’t too bad except for the fact that it took a lot longer than expected.
Hope this helps.
Matt
Matt L., Thank you for this comment! I had been trying to figure out which sprayer and tip to use and based on your comment I got the LTS15 (same as X5) and a .021 (521) tip and used the Behr waterproof paint with no issues. The spraying took me a little over 5 hours for two coats as well but most of that time was letting the first coat set. For others thinking of taking this on, I did underestimate how much paint would be in the air. Use a respirator (not just a dusk mask) and use plastic to cover anything in your basement that you don't want covered in white dust. Make sure to tarp over doorways to the rest of the house as well. I did not have the top of the stairs tarped when I started and I quickly regretted it.
How many gallons did you end up using, and what was your square footage?
Did you etch your concrete walls before painting them? I've read it helps the paint to adhere better.
Yes, I've heard that as well... for concrete walls. But not for cinder block walls, just to be clear. It's vital to etch if you're painting or staining a concrete floor - I'm not so sure how important it is for walls as they wouldn't get any wear or tear, the proper paint should adhere without issue.
I'm not a painting expert but I did sell paint for two years as a teenager.
Jason
Hi Jason,
May I ask you please if you think that is better if I use (instead of Behr Waterproofing pain) a waterproofing rubber membrane applied with a trowel, and after that install the 2'' rigid insulation over? I don't see any issue with this...let me know your thoughts. Thank you very much.
Hi Costa - I can't say that I'm familiar with rubber membranes for waterproofing. Sorry I couldn't be of more help. Good luck on your basement! - Jason
I have a 2 year old house that had some issues with the snap-ties leaking, the walls were injected, and I haven't had an issue since. I was told by the person who repaired the leaks that waterproofing paint causes cracking and leaks by not allowing the moister to flow through the concrete normally. He stated that when you apply the waterproofing paint, the water pushes against it, causing pressure and ultimately cracking and possibly leaks. His recommendation was to leave as much space between the foundation and framing as possible (maybe a couple of inches, and use 6 mil barrier in the back of the framing. This will allow the foundation to utilize the air circulating behind it to stay dry without undue pressure on the concrete. You obviously lose some finished space, but said it would be well worth it to avoid any issues. What do you think about his theory?
I think he's right that you don't want it right up against the wall with no breathing room. I typically recommend 3 to 5 inches of space between foundation wall and framed wall. - Jason
My masonary block basement walls have flakingand bubbling paint that is very easy to remove with a brush. No actual water running down the walls. It is not on every wall and shows up mostly after a very wet winter. My questions is the previous owner, house built in 1965, painted the walls with what I call interior room paint that you would paint your living room with. I have scrapped the flakes and bubbles but want to know Does all the paint have to be removed in order for Drylock to work?
Hi Linda - I'm not 100% sure but if you scrapped off all of the loose paint then you should be good to go. Drylock will have some more details for you on how to apply their product. Good luck! - Jason
My parents have bought a new home and are looking for a way to ensure that their basement is protected. It was cool to learn about how waterproofing helps to prevent water from condensing between your drywall and concrete. I hope that I see my parents soon so that I can share this article with them and help them to protect their basement from water damages.
Hydro-Seal 75 is the way to go here, rolling with a 1/2" nap roller instead of spaying with a Graco 433 or equal sprayer. 2 coats applied at a rate of 150 square feet per gallon should do the trick.
Prep with TSP by just washing the walls/floors using a bristle brush working from a 5 gallon pail with 1 to 2 cups of TSP. Apply the Hydro-Seal right over a damp surface after washing!
Hydro-Seal is a water based epoxy that is mixed prior to application with paint rollers, brushes or sprayer. Once mixed, Hydro-Seal needs to be applied in 30 to 40 minutes so we mix 1 gallon at a time and 1 guy rolls and the other guy cuts the edges. This product works great, looks great in a white or Gray color and works on the floor as well. For patching we just add some Portland Cement, or Hydraulic Cement or concrete sand mix to the Hydro-Seal and make a waterproof mortar that is skimmed with a putty knife or trowel. Clean up is with water .
We typically will wash and apply two coats on walls and one coat on floors in one day if doing the entire basement. Then the 2nd coat on the floor will take a few hours tops. No smell, no solvents and a very easy application that does not peel and stops water better than anything out there.
I am finishing a basement with no water issues and has a 25 year old Drylok coating. I've seen the corny Flex Seal commercial and was wondering if anyone has used this product on basement walls?
Why wouldn't you just use Drylok again?
Great tips Jason & Adam. Thank you!!
Looks like I'm down to DryLoc (Latex based) vs. Behr WaterProofing Paint (Acyrlic) for painting my existing below grade (poured in place) concrete foundation wall. Going to patch some of the tie rod holes with hydraulic cement first and then apply two coats of either Behr or Dryloc.
No water problems in the basement since I got the main water line repaired 18 months ago. But I have to run a de-humidifier regularly down there about half the year. I'm guessing when you open up the HVAC returns to air-condition the basement area, that will eliminate most of the humidity down there.
I'm based in Atlanta (Climate Zone 4), if it matters.
Also quick question on the Graco Magnum X5 Airless Paint Sprayer. The online info I'm reading says the max tip size you can use with it is .015. How are you able to use the .023"-.025" tip with the Graco Magnum X5?
Thanks.
Any respiratory protection required for this paint?
Hey David - Check with the label on the can but I believe you just need to open all windows and doors. Again, double check with the manufacturer.
HI
We had a water heater relief valve leak that compounded what seems to be a very slight foundation leak...since we have been in our house (built in 2005) for almost 10 years with a fully finished basement (wall to wall) with not a hint of a water issue until the water heater fail and removal of the wall to wall!
We are re-finishing and want to apply Drylok however the wall framing with 2x4's along the floor is still in place. Would spraying Drylok behind & under the framing to get to the wall-floor seams work and would Drylok work with the Graco sprayer?
Thx
Deb
So waterproof paint and then solid insulation as a moisture barrier over the paint? The walls are painted already, but have seen better days. Should I repaint them first, then stick up the insulation, or just lay the insulation over the existing painted wall
Hi Adam, what do you think about the brand Radinseal, heat of them, they claim their products is the bomb?
Sorry I meant Radonseal
Hey Chi - I think the real question is whether its the best concrete sealer. Sounds a little gimmicky to tout Radon prevention. I'd just go with flex seal...jk! Let me know where the crack is and how deep it is. I haven't found a one size fits all product.
-Jason
Did you use Radonseal? If so how did you like it? I'm looking at it for my basement.
I have painted basement walls & the moisture forms behind the cement wall and shows through as yellow/orange spots. I have tried different paints but the moisture bleeds through. I have had my basement floor dug up and put in new floor tile but still have this problem. Is there any paint I could I use to prevent this from happening?
Hey Rosella,
I think you have to seal the walls. Any paint repeatedly exposed to moisture is going to bleed.
-Jason
My husband has suggested that we get some waterproofing paint in our basement because of how moist the air has been getting, and it's good to know that it really does prevent water from condensing between the drywall and concrete. We've had issues with mold before in the basement, which is another reason we're looking into getting waterproofing paint, and preventing places for water to settle and form mold is important to us. We'll probably have professionals come to make sure that it's applied correctly, especially so that we get that seepage protection you mentioned.
Jason, thank you for all your comments. I have bought a home in Blairsville, GA, CLimate zone 4. Basement is poured concrete walls; area is one wall 26x 12 ft high, and 17x12 feet high. From all the information; Clean the walls, prep any holes with sealer. Use the Behr waterproof paint....hand brush around windows, etc. Use the sprayer..my area around 520 sq feet. Dry. Add XPS foam board, then put up studded wall (2x4) then if desired add fiberglass insulation for more R value. The guy I hired for a bid said just Dryloc, 2x4 wall, then add insulation. Ahh, from what I read NO BUENO...condensation on insulation, mold, mildew. Thoughts?
Hey John - I agree with your contractor. If you don't put up plastic or some crazy vapor barrier, your wall will be able to "breath" and the poured concrete walls will limit moisture.
-Jason
When insulatingbasement walls, use Rockwool vs. Fiberglass.
I had a lot of stains and efflorescence on my concrete walls I washed them and the efflorescence has come back (not as bad) I read hay it will keep coming back because of what it is. Should I just dry brush it off and then paint on my waterproof sealer? Also when I dry brush it not all of it comes off just the rough spots and it still has a white tint to it!
My cinder block basement walls are all completely painted already. There are some spots where the paint is flaking or bubbled out a bit. What would be your recommendations for waterproofing with paint/drylock in this situation , before I put up the rigid foam boards?
Thanks
I’ve just finished using drylok waterproofer paint on my basement walls and parts of the walls are starting to blister. Was wondering what can be done to fix this issue?
Having trouble deciding what to do with my basement. Poured cement walls in a 1929 house have stucco in some areas and several layers of paint. Some of the stucco is hollow sounding in places.
There are no cracks anywhere but water vapor and some seepage has caused paint to bubble/peel and stain the walls. 99% of this was from the previous owner doing no water management maintenance. I’ve dealt with those issue and have had no seepage or moisture over the past year.
So now what do I do with the walls and the floor? Scrape and repaint? Does everything need to be taken off down to the bare cement? Can I patch the stucco and repaint? If I repaint, will it all just peel off again eventually?. So many questions and so many options have me at a loss of what direction to go. Please help.
If your foil test showed that water is soaking through your basement walls and leaving them wet, seal the interior of the walls with a high-quality waterproof paint, such as DRYLOK White Extreme Waterproofer (available from Home Depot ). This type of sealant comes premixed and goes on just like a coat of paint. When waterproofing basement walls with it, brush or roll the paint on thickly enough to fill all the little surface holes, then allow it to dry fully before a second coat is applied. When completely dry, the sealant forms a watertight bond to keep any more moisture from seeping through. A five-gallon container treats approximately 500 square feet of wall.
Would the Graco x5 sprayer w/ a tip 0.023 or 0.025 work w/ (Lowe's) DryLok pro? I assume it's thicker than DryLok Extreme.
We moved in just over two years ago. House is on a pretty steep hill near the top but not quite. The previous owners had excavation work done to help drainage.
Last summer, we had torrential downpours that filled the window wells and got into the basement. We cleaned up, but it had seeped too far. A week or two later, my wife smelled mold and mildew, so I tore out the wall paneling and carpeting, plus pad.
It's now down to concrete on walls and old asbestos tile on floor. We'll cover over that tile soon, but we need to tackle the walls first so the septic backup replacement can be fixed. (Yeah. It was a busy summer.)
Will the Behr paint cover over the existing paint remnants from years gone by? I've read conflicting opinions. If I have to strip these walls bare down to nothing and clean out every little porous hole, I may just finish this project shortly before my ninetieth birthday.