Basement Waterproofing

Just thinking about basement waterproofing puts me on edge. Why? Because my basement had all kinds of weird water problems. If you're anything like me then you really can't imagine finishing your own basement until you've got this whole water issue under control.

Moisture in the basement is a huge problem. But there are answers and they won't cost your thousands of dollars.


Basement Waterproofing Paint Application

Basement Waterproofing Paint

Okay, so you've done all of the exterior waterproofing steps and you still have some water seepage through your basement walls.  What do you do?  Does basement waterproofing paint really work? Well.... that depends. Read this post to see if it's right for your basement.


exterior basement waterproofing downspouts

Exterior Basement Waterproofing

Before you spend a single dollar on getting water our of your basement - follow these tips to keep it from getting in there in the first place. Since executing these exterior basement waterproofing  tips - my sump pump hasn't gone off a single time. Not even once.


interior basement waterproofingInterior Basement Waterproofing

No cracks? You're telling me your basement is crack free? Maybe, maybe not. Here are 3 places water might try sneak into your basement. These are all things you can fix from the inside of your basement. Don't let water be the boss of you! Own that dry basement!


basement insulation rigid foam boardIs Rigid Foam Insulation (XPS) Right for Your Basement?

If you live in a colder climate (like Michigan, Canada or the North Pole) or if you're really worried about moisture problems on your basement walls you might want to consider using rigid foam board to insulate your basement walls. This goes up before you do your framing.

Adam installed it in his basement and wrote this article to take us through the installation process and pluses and minuses of using it.


dehumidifier with a hose hookupThe Best Basement Dehumidifier and 5 Things to Check Before you Buy

Once you've done the interior and exterior waterproofing steps you probably will still want a dehumidifier for your basement. To make sure you get a good we wrote this review of our current favorite.


Sump pumps with a float switchSump Pumps - Don't Make These 3 Mistakes

Sump pumps suck. It's basically admitting to the universe that you are expecting to get screwed over. But...  you will most likely need one and in that case you want to do it right. BEFORE finishing your basement, you want to make sure you can handle any basement floods that come your way.


basement finishing jasonWe're just getting started with this basement waterproofing content. Adam is writing a lot of the content. You are going to love his writing style, cause it's just like mine!

If you have a basement waterproofing question please leave a comment below.

Cheers - Jason

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Questions and Comments

Click here to ask a question or leave a comment.

  1. Tim Leonard says

    I am starting my basment project and I am inspecting the walls in the concrete so I can repair them, then i will damp proof the walls. Do you have any suggestions for products to repair cracks and also for damp proofing? I have heard mixed reviews about products like drylok. Any other products to recommend?

    • says

      Tim - Adam presents some options for basement cracks on his interior basement waterproofing post. Once your cracks are properly filled in I've heard that drylok is effective for keeping "dampness" out. In other words, it won't stop a full on water leak, but will keep out air moisture.

      Good luck finishing your basement, you can definitely do it!


    • says

      Hello Allen - THANK YOU! I didn't realize my page structure had broken, I've fixed it, you should now be able to see everything. Good luck finishing your basement! - Jason

  2. says

    Hello! I've been following your web site for some time now and finally got
    the bravery to go ahead and give you a shout out
    from Dallas Tx! Just wanted to say keep up the good job!

  3. Dawn Slinsky says

    Jason, what do you think of painting basement floor/walls with Kilz? I do not have any water issues, but have had trace amounts of mold which we washed/bleached. Would Kilz be an added protection?


    • says

      Yes, you should probably use a sealer / blocker on the floor as an extra precaution. Kilz has a floor specific product that gets good reviews. You can't use "regular" wall Kilz on the floor though - you'll need a concrete flooring specific product. Something like this. - Jason

    • Adam says

      Bill - My buddies sprayer is a 395. It is a nearly top of line model as he does a lot of home projects and such that require painting. The waterproof paint is thicker than normal paint and therefore required the larger tip sprayer than would be sufficient for normal paint. You could try using a smaller tip, but I would be worried it would clog you tip.

  4. Tom says

    A couple years ago we had bad/heavy/ continuous rains here in the DC/ Northern Virginia area where I noticed moisture. Nothing flowing but noticeable on the concrete floor so I tore the insulation to see the culprit/cracks. There is no spout in the area outside. Since then I always check the spots when we have heavy rain and there has been no moisture. You think it's worth addressing? If so should I address just that area or the whole basement just in case.


    • says

      Hey Tom - I remember that, we had an insane amount of rain that week. From your description it sounds like the moisture was on the floor? When you say you looked for the culprit on the walls... did you find a crack or moisture or no?

      My guess is that the water table rose up and the moisture came from under your basement slab, not from the walls. If that is the case, it is like that could happen again. Usually the water comes in through weak spots like around the footings. Unfortunately the best resolution is to install a sump pump as it's nearly impossible to make a concrete basement floor water tight. You might also try extending your down spouts (all of them) away from the foundation of your house. This is what solved my very similar issue.

      I hope that helps. For what it's worth, I had a very similar problem, before I fixed my drainage situation with the down spout extension.

      Cheers - Jason

      • Tom says

        Hi Jason,
        Thanks for the quick reply. The leak wasn't from the floor. There is a crack on the wall where there is small weak section of the crack had some leakage/moisture that dripped to the floor. Seeing on the floor was the only way I saw it since the actual cause was behind the shiny insulation. You think Behr waterproof paint to the specific area in addition to redirecting the spouts away from the house would do the trick? Or do you think I need an expert help

        • says

          Tom - Aaahh, I see. This is just my opinion, so take that for what it's worth, you can solve this with a combination of the down spouts and drylock or waterproofing paint. If the crack is really big you may need to fill first. (read this article from Adam if you haven't yet)

          Good luck! - Jason

    • Tom says

      I have put extensions on my downspouts but I finally realized what caused the was the sump pump drainage pipe. I never put one on. In combination with some sealant and waterproof paint I should be good.


  5. says

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  6. Joshua says

    Jason and Adam, I'm a HUGE fan of the site. You've inspired me to finish the basement in my future home. My wife and I are looking for our first home and the biggest thing I want to do is finish the basement by myself. However, we live in southeast Michigan and I'm terrified that I'm going to spend $15k to finish a basement and have it flood. I've read all of your basement waterproofing tips twice and I have to say I'm still a little scared of flooding. Mostly because this house will be new to me. I wont know if its had a water issue in the past. Are there any warnings, tips, or hints you can give me so I know what to look for in the basement when purchasing a home? I have no idea how to tell if a basement has a flooding, leaking, seeping, or weeping issue. Any help would be great. Thanks!

    • says

      Josh - Looking for warning signs is probably a whole article in itself. In fact, I'm writing that down now to my article list. Briefly, you can look for stains on the walls and or concrete floors that show whether or not water may have risen up there at some point. Sometimes this shows up as a line of brown, dirt like stain where the water lift up dust/dirt and pushed it all to the edge. You can also check the wood framing on the floor under the stairs - if it's flooded you may see some discoloration on the framing. - Jason

  7. Miriam says

    hi. We're just starting the basement. I've found 9 cracks that are about 5' high on the walls extending to the floor. I don't see any stains around them. We did get water 3 times in 8 years during very heavy storms. But when I got home from work I couldn't tell where the water came from. I'm guessing 1 area was by an exterior door that had a drain that was plugged with leaves. There was just a little water that may have run to a low spot of the uneven floors. I do have a sub pump. I'm questing if I should have these visible cracks fixed.... Or am I wasting my money???

    • says

      Hi Miriam - Sorry, I'm not a basement wall crack expert so I can't tell your for certain - BUT - at 5 feet I would personally want to have those addressed. Perhaps ask a basement finishing company in your area to come give you a quote - and ask them specifically about these cracks. - Jason

  8. Danielle says

    Hi Jason, We're in Georgia so I'm assuming our basement will be more in line with yours climate wise. It's a walk-out basement and I haven't seen any moisture issues. What did you do to waterproof your basement? (Seems like these articles are for Adam's midwest basement--definitely a different beast).


    • says

      Hi Danielle - Yes, we really need someone from the South to write a series of articles on moisture control for Southern basements. Then we'll have covered each of the regions. I didn't do to much. We do have high humidity here in Virginia, especially closer to the "swamp lands" we all know and love as Washington DC. I have a dehumidifier that I run in the summer - if I leave it off the humidity gets to around 50-55% in the basement - not terrible but not great.

      Still, I haven't noticed any mold at all, and almost (almost) no musty smell. The big difference is that my humidity season is much shorter than yours in Georgia. By the fall we're back to a normal 30% and in the winter it gets super dry, to the point we're I'd like to add humidity back in.

      My primary recommendation is to design your basement to hold and run a permanent dehumidifier. Once that runs automatically at night and drains continuously into a drain so it's almost maintenance free.

      Good Luck! - Jason

  9. Tyler says

    So I'm finally getting to start my basement. The house was built in 2013 and is framed around the border with insulation behind plastic. Is it safe to say the contractor probably waterproofed or should I still go through this step?

    • says

      Hi Tyler - Unless you see signs of water issues, it's safe to assume that you're ready to begin and that water in your basement isn't going to be an issue. - Jason

  10. June says

    Hi, I am pricing interior waterproofing for my basement. I have one problem area. Is it safe to get just that wall done, or do I need to do all 4? Thanks, June

  11. Amy says


    I'm finishing a detacted cinderblock garage in a humid climate. Once I cool the interior I know the cinderblock will sweat and could cause the insulation to mold. I don't want to waste inches with foam board. An engineer suggested I use HLM 5000. Is there anything else that you'd recommend using that isn't as expensive?

    Thank you!

    • says

      Hi Amy - I'm not familiar with HLM 5000. Sounds like a cool top secret government experiment. Most people in your situation like to use XPS, rigid foam board. It's a bit expensive but seems to help that exact issue. Good luck! - Jason

  12. Len says

    Jason, thanks for all the great info, especially for a newbie. We are starting to finish our basement but I'm in a sort of paralysis by analysis stage w/ the waterproofing aspect.
    We completely remodeled our house 3 years ago and dug out an addtional 20 feet of new basement in addition to the existing basement. The builder put up foil faced insulation against the new concrete walls. I contacted another builder from a link on your site and he strongly recommended I take it down and put up XPS because he said mold will definitely develop. Did you not take your insulatin down because of cost? It'll cost me almost $1K in XPS alone. We live in MD near you so in a similiar climate. I will say we already had a crack in the new basementwall, so had a major leak in the spring right where the new basement wall meets the old basement. I had a company come out and patch it on the outside and inside.
    Again, I'm not sure if the XPS is worth it other than peace of mind?

    • says

      Hi Len - Nope, I left my insulation just as it was installed and did not use XPS. I haven't had any issues. XPS is great, but as you're noticing it's also expensive, and is it necessary??? If foil backed insulation was really that bad there would tons, I mean TONS, of homes with mold issues. Many of the major new home builders using regular foiled insulation. XPS is the exception, not the rule. Again, really depends on your specific situation but for me - I didn't need it. Hope that helps, good luck! - Jason

  13. Leigh says

    Hi Jason! A year ago my husband agreed to finish our basement. I bought him your online book for Christmas and here we are 12 months later with absolutely nothing done. His fear is with the water we get in our basement after heavy or continual rain. We do get a stream in from 2 or 3 areas in the basement. I'm at a loss as to what to do. We have 5 kids in a 3 bedroom 900 square foot house and I need that basement space usable for my sanity!!!
    Thanks for your advise!

    • says

      Hi Leigh - Did he watch the very detailed video on how to handle this water issue? This is critical! It's not uncommon to get hung up on starting because they are worried their new basement will just get flooded. Watch the water videos, they will definitely help. The most common and least expensive solution is gutters with downspouts that are extended at least 6 feet from your foundation. Please have him email if he has any questions. This is your year! Reboot! - Jason

  14. Rob says

    So I'm looking to finish my basement room by room. We just moved in and my first room is planning to be a wine cellar. All the books suggest some type of moisture barrier. Either spray foam or 6mil plastic. I was thinking DRYLOK then maybe the foam board and then regular insulation then green board (because of the humidity level recommended). Should I just skip the waterproofing step? The basement is dry except when we had a broken water main and the French drain couldn't handle it all.

  15. Michael a. Massetti says

    Jason ,
    how do I get your free basement cost estimator . I signed up and never got a link ?
    like the emails and references . starting to collect information on my region ;Midwest ; chicagoland area. gonna use ridgid foam, 1/3's and drywall to warm and finish basement. have 3d home design to do floor plan.
    thanks for your time.
    Michael a. Massetti

  16. David says

    I've lived in my house with the basement unfinished for 7 years now and never had any water in the basement. Also we're up on a hill with a french drain around the outside perimeter. Should I still water-seal the walls?

  17. Emily says

    Hey Jason!
    We currently bought an older Home (1950's) and had to gut the entire basement! over the cement walls was this fake wood paneling. When we pulled the fake wood away there was mold and mildew on the concrete. Yes, we have our fair share of cracks all over!! I was wondering what my options were. The previous owner had painted the cements walls so I'm not sure if I can put a sealer over that or not? Do I fill the cracks first and then seal? Pretty much I'm saying help me with an order of what to do and what to purchase.
    Also, at the bottom of the walls there was beaver board. We ripped it out but now have the open holes.

    • says

      Emily - Super curious... what the heck is beaver board?? It's a new term to me, guessing maybe it's base trim board? OK, let's get to the cracks and such. This isn't my area of expertise but I know the general order. 1. Remove all of the old stuff, you don't want to paint over it. 2. Fill the cracks. 3. Reseal the wall. Then give it a couple weeks and see if you see any moisture issues. We can go from there. - Jason

  18. Thomas says

    I was thinking of painting my basemnet floor before laying down carpet. Whats ur recommendation when it comes to the basement floor.

    • says

      Hi Thomas - If you're going to put down carpet I would recommend sealing the floor, I think it helps to keep dust down even though you are covering it with carpet. Paint is a sealer but a better choice would be a pure concrete sealer that specifically formulated for that job. Hope that helps. - Jason

  19. Keith Crum says

    Jason – I’m currently in the midst of refinishing my basement (I’m helping my remodeling buddy do the work). The original owner did a terrible job and I had serious water, black mold and mildew issues for years. I’ve spent weeks researching waterproofing agents and here is what I found out; UGL is a temporary solution and won’t stop major leaks. It’s only guaranteed for 15 years and once it fails you have to ripe out everything you worked so hard on and start over. The walls have to be pristine for Drylok to even remotely work or the warranty to be valid. Through my research I decided on a product called RadonSeal. You have to do the same block wall prep, but application is easy to accomplish with a garden sprayer and it has no discernable odor. RadonSeal soaks into the block and creates a seal within the block and also pushes out the efflorescence. It’s pretty amazing and I’m very satisfied with the results.
    After completing the RadonSeal application and relocating my entire water system (heater, softener, pressure tank and reverse osmosis) to the other side of my basement and framing I had 3” of closed-cell spray foam applied to the walls of the remodeling portion of my basement and the entire band-board perimeter of the house. Expensive, YES! Worth it, ABSOLUTELY! Closed-cell insulation creates a rock solid moisture barrier and additional peace of mind (not to mention an R-value of 15-18). The insulation was installed two weeks ago today and the difference in the basement humidity level is absolutely amazing. It was so bad before that the HVAC boots had condensation dripping from them when the AC was on, even with a 70pt dehumidifier running 24/7.
    That same week I had “purpleboard” drywall installed. Purple-board resists moisture, mold and mildew and is becoming the standard over “greenboard” because of its additional resistant properties. Again, it’s more expensive (about $20/board). But, if you’ve had the water issues that I’ve had its well worth the extra expense.
    You’ve got great tips on your site, keep up the good work!


    • says

      Thanks Keith! This is great info. Yes, you can solve really bad water issues. No, just painting the walls won't be the answer. Great work! - Jason

  20. Matt says

    Hi Jason
    We just had a new home build and now we are wanting to finish the basement . But we wanna put some kind of waterproofing on the block walls before we cover it . Is there any kind of waterproof sealer you'd recommend using that we can do ourselves ?

  21. April B says

    After removing panelling and foam installation from my basement walls i found some mold spots, some cracks, and the walls have been painted light green. I have since used a grinder with a diamond bit, and applied hydraulic cement to those cracks. Im wondering if i should use a sealant on my already painted walls... unsure it is regular paint or old sealant. What should I do.??

  22. Lisa says

    Hi, my basement has moisture stains in the middle and bottom of one wall. I am going to have company waterproof one half of the wall with tar and clean out the footers with jetted water. Do you think this will be ok for now. Will cleaning out the footers help solve the issue? I'm only doing half the wall b/c the other half I did stamped concrete, didn't think I had a problem. Although most of the staining is on the other half that is not stamped.

    • says

      Hi Lisa - I can't say that I've ever of heard of "cleaning out the footer". If you have water staining then you certainly have or at one point had a water issue. Do you know how long ago that was? I also have not heard of using "tar" to waterproof a wall - seems like something they might have done in the "olden" days. I'm not saying I know it won't work, I'm just saying I haven't heard of these two solutions. I'd love to hear in update if this does indeed help waterproof your basement or what it is if you have any other info or links.

  23. Lisa says

    Hi Jason,
    I noticed staining when I first moved in in 2010. I cleaned and painted the walls with Behr basement and masonry waterproofer. I saw a little stain come back and then sealed the gap outside the house between the outside brick and concrete where I thought water was getting in. I thought it was ok after that. I never had any water that I've seen since 2010. Just recently I noticed more staining come back. I'll let you know how it goes. The footer I was told may be blocked by dirt etc. and the thought was to get to the footer and clean out any debri that may be clogged in some spots. I hope it works.

  24. Brett says

    We are getting ready to finish our cinder block basement and are in the waterproofing stage. We don't get any water on the walls or foundation but have some efflorescence on the block. We are insulation with rigid XPS foam. Do I need to drylok the walls before putting the XPS up or will the XPS be fine by itself?

  25. Heath says

    A few years ago my sump pump failed to work. It didn't overflow but the water level was high up to the top. I saw some damp concrete sections on the basement floor that appeared as though the water was running under the concrete trying to come up through the floor. I replaced the sump pump and it hasn't happened again. Do you think that may have cause some permanent damage to the floor ?

    Also when I purchased the house there was a couple of stress cracks that had been repaired professionally in the basement both ran from different windows (these windows have dug in window wells on the outside) This year I have noticed a small amount (around 1 cup or so) of water that that has come in from these stress cracks. I was planning on having the cracks reinforced in a similar manner that was done in the past (steel rods with some kind of polymer I think) redone. Anyway I guess my question is - do you think there is more going on here and should I get a professional in to have a look ?

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