Basement Wall Waterproofer Review: Super Thoroseal

October 6, 2009 | by Fred (email) |


Two years ago, we waterproofed over 1000 square feet of cinder block wall in our mostly-underground basement. We applied Super Thoroseal to 500 sq. ft., and SunnyDry Foundation Waterproofer to the other 500 sq. ft.

[See also: SunnyDry Foundation Waterproofer Review]

When we ran that initial review, we promised a follow-on article with a review of Super Thoroseal’s performance, but like so many things, it fell off the plate. So here’s that review, two years later.

What is Super Thoroseal?

To bring you back up to speed, Super Thoroseal is a portland-cement based waterproofer that is sold in 35 lb., five gallon buckets at a variety of stores–most notably Home Depot, where we purchased it.  Super Thoroseal is suitable for a variety of waterproofing applications, including above and below grade concrete and masonry waterproofing.  It cannot be applied to painted surfaces.

[See also: Super Thoroseal’s Official Site]

Super Thoroseal claims a 200 PSI waterproofing capability, nearly 10 times the standard waterproofing available from paint-based solutions like traditional Dry Lok.  (Note: Dry Lok now offers a portland cement based solution as well).

Installation method is extremely important as the product will not work as advertised if the instructions for wall prep and application are not followed to a “T”.  I’ll repeat this because it’s important:  installation method is very important.  Do not short cut the installation or your seal may fail prematurely.  Alright, enough of that.  Here’s how to apply it:

How to Apply Super Thoroseal

Wall Prep: The walls must be cleaned of debris and efflorescence, wet (as in, with a hose), and the temperature must be above 40 degrees.  You can see Thoro’s online instructions & product sheet for more information on application specs and performance.

Mixing: Measure and add the appropriate amount of water to a separate five-gallon bucket.  Do not add too much or too little water. Add the Super Thoroseal powder  and mix with a suitable drill & mixing paddle until it becomes a pancake batter consistency.  Do not try to mix Super Thoroseal by hand, you will not be able to get a good mix. Super Thoroseal stays spreadable for about 30 minutes.  Do not pour water into the Super Thoroseal bucket.  The water must be poured into a separate bucket and the powder dumped on top!

Application: Wet the walls with a garden hose and apply the mixed batter using a tampico fiber brush (also available at the big box). Cover the walls thoroughly. Full seal occurs after two coats. Note: you must apply both coats within a 24-48 hour period.  Do not let the first coat stand for more than 48 hours or the second coat will not bond and seal well.

Super Thoroseal Coverage & Price

One five-gallon bucket runs about $25 at the local big box. Coverage is up to 105 sq. ft. and requires two coats to achieve watertight seal. We found Thoro’s coverage claims on the bucket to be accurate.

Super Thoroseal Water Sealing Performance

We’re pleased to report that after two years, Super Thoroseal is living up to its promise.  We have no leaks in the basement, and recommend this product to folks looking to seal their own basements.  If we ever do experience an issue, we’ll update this article with the bad news.

Update 10/16/09: Last night, we examined the wall in one of the corner areas on the wall and noticed a small section (about 2×2 inches) of the ST had de-laminated from the wall. It appeared that the Super Thoroseal in this area didn’t form a good bond and was a bit ‘powdery’ – it wasn’t well mixed.  I don’t blame this on ST and actually believe it may have been an error in our installation process (the first coat we applied didn’t follow my instructions here exactly, and we may not have mixed it well because it was our first try).  The good news is the issue appears isolated and not characteristic of the rest of the wall.  Also, there’s still no moisture in the area despite the rain we’ve had, which leads me to believe some of the ST is still clogging the pours of the concrete.  I will continue to update this post if we have any other issues.

Update 2/7/12: Our walls have been encased in closed cell foam insulation for more than 2 years now. We have had no issues whatsoever with either the Super Thoroseal or SunnyDry leaking.

70 Responses
  1. Kelli says:

    Wow, this review was so educational! I had no idea where to even begin with the process of using a waterproofer. Sadly, I don’t think this will work for my basement. But I’m enjoying learning about what’s available. Thanks for the great article!

  2. Fred says:

    Kelli, glad you enjoyed it! We’re very pleased with Thoro’s product…

  3. H says:

    Great information. Thanks for the review! I was skeptic of using Super Thoroseal ($25 x pail) because the price difference between this product and Drylok ($100 x pail). I just applied the second coat and hope; as you, state that it works great!

    Thanks again,

  4. Fred says:

    H – We’re still happy with the product. I will say that in one 2 inch by 2 inch area on the basement wall we recently had a piece delaminate. Now, that’s not characteristic and when we applied the Super Thoroseal, we didn’t follow my instructions here 100% …

    In fact, we applied the first coat and then let it sit for a week. We then applied two more coats. We still aren’t getting moisture in that location, I suspect because the ST seeped into the pours of the concrete.

    I think you’re real safe going with ST vs. Drylok — The Drylok product that is in the same size barrell gets a little more coverage, but doesn’t seal as tight as ST… Just make sure to follow the instructions. We’ve talked to a number of local contractors and they trust ST for this type of sealing job.

    • Ken Kishtok says:

      I am going to try ST just like you did on your home. wondering what you used to seal your floor. Do you think ST will work on the concrete floor where I just use the basement for storage and my workbench. Hardly any traffic down there. what’s your thoughts?

      • Fred says:

        Ken, most concrete slab floors are polished and ST will not adhere to them. You should not need to seal your floor. If you do, you’ve got a bigger problem with water drainage and need to look into a french drain / alternative method of taking care of the water. ST is also very coarse when it dries. Would be very hard on feet. It does not dry smooth like a typical basement floor.

  5. Tammy OHagan says:

    Wow! Love the article. Hubby and I have a huge two stall commercial truck garage on our property and have been debating if we should attempt to build a home out of it. One of our main concerns is that when the garage was built 30-35 years ago, the previous owners did not lay any type of moisture barrier before pouring it’s concrete floor. The drainage is awful and the floor is always wet. Two rooms were built into the back of the garage and they are full of mold. (as I’m sure the trusses and rafters are also). This garage is 32′ x 48′ with 12′ ceilings… This (in my humble opinion) would make a great start for a house!

    Thanks for the review!!!

    Tammy OHagan

  6. Art Glick says:

    Thanks for taking the time to post such valuable information. We, too, are preparing to seal a block wall and found your advice to be most helpful. I notice that with most of these products, there is a need to remove any efflorescence. Did you have to do that, and if so, how did you do it? We’ve seen a variety of conflicting advice on the subject.

  7. Tim Schmidle says:

    RE: Basement Wall Waterproofer Review: Super Thoroseal

    Loved the review on the Thoroseal and SunnyDry waterproofing. How is the SunnyDry holding up after 2 years?


  8. Fred says:

    Hi TIm,

    SunnyDry is also performing well.

    In November, we had the walls insulated with closed cell foam, permanently closing up our work, so it will be hard for me to monitor further progress unless something really goes wrong (which I certainly hope it doesn’t).

    Can’t say it enough – prep instructions are important.

  9. Cole says:

    Any advice on basement floor sealer. Will this work on the floor as well?


  10. Fred says:

    Cole, this won’t work for basement floors… Unfortunately, I don’t know a good product for that. Have you looked at something like Schluter’s Ditra? What are you planning for a final walking surface?

    • Jeffrey Willis says:

      Hi Fred,

      Thanks for your contribution on ST. I just checked it out at HD & thought I had the best product for my concrete basement floor, which is slightly damp in a few spots but mostly dry. Do you say it “won’t work” on this surface if it is smooth or is there another problem? Can the current surface be roughed up first?

      If somehow acceptable, can another product be used to top the rough ST, resulting in a smooth surface? Maybe Top n Bond or similar? I want to adhere carpet tiles for finished surface.

      I will also check out Schluter’s Ditra.



      • Fred says:

        1 – smooth surface will have bonding issues. You might be able to “rough up” and etch the surface but I’m not sure.

        2 – when we installed ST, the instructions specifically state not to top coat (or even paint the surface). Doing so will void your warranty. I know that ST is not recommended for floors.

        Also, it’s worth noting that ST dries “rough” – like extremely coarse sandpaper. It wouldn’t be a good walking surface.

  11. Derek Taylor says:

    i have cut back the existing plaster and render back to the brick/cement block. Should I apply the Thoroseal onto the brick/cement block or between coats of new render? and what plaster finish should I use

  12. Fred says:


    ST should be applied directly to the cement/brick. Note that you can’t apply anything directly to the ST after you waterseal with it (e.g., no painting, plaster, etc). You will have to frame out a finished wall.


  13. Lou says:

    My question is i did not see on the instructions for ST you had to apply second coat within 48 hours. I have first on so far concrete wall but its close to being 48 hours and plus. Is this going to be worth putting/attempting second coat of ST or is there an other product to put over ST for a second coat? Please Advise
    Thank you

  14. Steven says:

    After this winter we had here in the Philadelphia area, we have numerous small cracks in our stucco finish. Our contractor wants to paint/cover the small cracks with ST. We are looking to paint the house later this summer. Is this a good idea? Please let me know.

  15. Mary says:

    I had thoroseal recommended to me by a mason for waterproofing decaying stucco over cinder blocks and for cement floors. Both surfaces are painted and that is obviously a BIG issue.
    I spoke with the company and many of the elements of the powder are carcinogenic-how did you all deal with this? did you move out of your homes. It was part of the EPA superfund cleanup-so I am worried about kids and dogs and ourselves being in the house.
    If we cannot use this this product for all of the above stated reasons, what do you recommend for waterproofing? Are all of these mixtures carcinogenic?
    Thanks for your help.

  16. Charles Sferrazza says:

    I want to seal my cinder block basement wall. There is a white salty-like substance coming through the wall. I’ve been told it is lime. Will Thoroseal stop this? Also the people I bought the house from painted the walls with I believe to be a ceiling paint. What must I do to use thoroseal? Thank you for your attention. Charlie.

  17. j marcotte says:

    We had all 4 walls of our foundation replaced about 3 years ago. Unfortunately, the split faced block used above the ground level was defective( an inappropriate “lighter” mix was used, and after many applications of clear water repellant on the outside, the contractor assured us that thoroseal, applied inside was the best choice to stop the walls from becoming saturated every time rain hit the outside, above ground, block. The first area that it was applied to was obviously not mixed properly- it looks all uneven, and very “thick”, also it was applied to dry walls. In these ares there is staining appearing, that looks “wet” and discolored, but is dry to the touch. I am concerned that the application was botched, and am wondering if there is any way to remove this stuff and reappply it, or, is there any way to “fix” what was done? We are at our wits end, as this job cost us $55,000.00 and a load of headaches. Any thoughts?

  18. Mary says:

    I am wondering what happened to all of the advice that was being given by the website owner for all of us who don’t know what to do to wateproof our basements. I think this is a great forum, but if no one tells us how to handle our issues we are just venting the same issues to each other.
    Thanks for listening.

  19. Mary Gervasini says:

    My mom’s fixed basement just got about 5 inches of water in it due to the bad flood that just recently happened in our area. We have to take down her paneling and redo tile on her floor. We had someone come in and quote us around 1400.00 to put thoroseal on her walls. Is this a good idea? He says he can make it decorative??

  20. judy says:

    I don’t think thoroseal will stop water from pouring in… it seems to me (it is on our walls now) that it is better suited for a “dampness” of the walls, or small crack repair. We had our contractor apply it, and, unfortunately, the first day it was not mixed properly, so the first walls they did are not reacting well, in fact, water stains are on those areas. Proper mixing and application seem to be VERY important. As for the price, I am not sure what labor cost are where you are, but you may want to do some research-Home Depot sells the stuff, however, like I said, application and mixing are the key, so it may be worth paying an experienced person to do this for you. I am just a homeowner, but this is my opinion- we do have it on our basement walls. Hope this helps!!

  21. steve says:

    I used thoroseal on a basement wall it was some block and some poured concrete, it was painted in a lot of areas but we cleaqned it well and applied as directions said, we did two coats, and im telling you this was the driest basement ever and before that this basement was damp and wet. i miss that base ment so much. Thoroseal beats anything, just prep area wet walls and mix with paddle mixer and pancake mix consistancy . best investment for a basement you can do , been recommending thoroseal for years. i dont know why mine work over paint, didnt remember it saying that, i have painted walls now and im gonna try it. good luck

  22. Tom Roth says:

    Having been in the commercial waterproofing business for a number of years I can honestly say that I would not rely on any waterproofing system that is applied to the opposite side of the wall to which the water is pressing against. Waterproofing should always be on the same side of the wall as the water. Next, avoid using anything other than concrete for a wall you wish to waterproof. Stick to products that remain indefinitely elastic and pliable such as rubberized asphalt. Typical manufacturers are Laurenco or Gaco Western LM60. Follow their installation guidelines and you should be all set. As for Thoroseal I have used it to reduce pourosity of a substrate prior to applying the rubberized asphalt products, but never alone for preventing water penetration. For the record I have worked on buildings that are over 40 feet into the ground. Hope this helps

    • Sarah says:

      Tom Roth- interesting, you’re saying it is possible to put something over the Thoroseal walls? I just had a contractor coat all my subgrade cinderblock basement walls, two coats, of TS. The reason I came to this forum was because it’s been 2 weeks and I can still smell (or more like feel in my lungs) the smell of it. It’s sort of powdery toxic. Then, above, I read that it’s carcinogenic?? And, I don’t know if it was applied properly, with walls wet first. i don’t know if the guys cleaned the walls in any way first either. The guys used some sort of blower/sprayer with a compressor going. I was disappointed to find out afterwards that I can’t paint over it… But, you said you’ve put “rubberized asphalt products” over it. Would that seal in the Thoroseal smell, and hopefully not smell worse? Is it carcinogenic? Maybe using rubberized asphalt products over the TS would also seal over anything carcinogenic. I see you posted in 2010, so…hope this finds you because sounds like you’ve got most experience of anyone on here.

  23. Tom Roth says:

    For those of you with a concrete block wall for a basement your in a real pickle. Best bet is to dig all the way around the house and apply a rubberized asphalt product to a clean substrate then install drain board such as Henry DB200S and new drain tile wrapped in filter fabric and backfilled with pea gravel. Tie the drain system to a pump and slope the finished grade away from the house. Alternatively, you could drill either through the wall or down through the dirt and inject a hydrophobic material to create a curtain of water resistant material. This is a specialty trade and can cause the wall to crack due to the added pressure on the exterior of the wall. You need someone who has a substantial amount of experience to do this type of work, and I would check with a number of commercial waterproofers in large metro areas to find out who to use. Don’t try and find them in the Yellow pages. If you have a concrete wall that is leaking at a crack or a joint in the wall you can inject the crack with a product that expands to seal the joint. This is also a specialized trade and you should seek the advise of a professional commercial waterproofer working in a large metro area for the proper experience. Lastly, if you haven’t installed a commercial grade waterproofing system and your basement has real water intrusion problems you should avoid installing a finised basement using carpet and insulated stud walls. If you really want a finised basement stick to products like tile for the floor and a breathable paint like TNEMEC for the walls or faux stone that is glued to the wall. Use throw rugs over the tile if you want something softer on the floors. Otherwise, you risk creating the perfect enviroment for Black Mold.

    PS: The black stuff your cheapskate builder bought at the local home center doesn’t count as Commercial Grade Waterproofing. To do it right takes planning and attention to detail. You should also be careful of fumes and fire when working with this stuff.

  24. Stephen Herrera says:

    I am planning to use Thoroseal as a waterproofing coat on my concrete roof deck. 2 months ago, the roof deck was waterproofed using a locally produced product. The waterproofing product used is a specially formulated acrylic polymer designed for compounding with Portland cement. However, this product did not live up to its promise as I have water leaks in several spots in my roof.

    My question is: Can I use Thoroseal on my roof deck on top of the previously applied local waterproofing product?

  25. Fred says:

    Stephen, you’re best bet is to get in touch with Thoro Products and ask this question yourself. They make little warranty beyond their product working when directly applied to stone or masonry. My guess is that if the underlying product can bond with portland cement, you might have a shot, but I doubt they’d be willing to give you an answer.

    If this is a flat surface, I should warn you that super thoroseal doesn’t really go on “smooth” – it will definitely be a rough surface, no matter what. And I’m not sure how good the seal will hold up under foot traffic. It seems like the deck should have been designed with a waterproof membrane and drainage system. I assume its old?

  26. Stephen Herrera says:

    Fred, thanks for your immediate comment . The roof deck I mentioned is a new one, almost 6 months old. And yes, we are talking here of a flat surface. Definitely, it won’t be subjected to foot traffic.

    The original roof I had was made of corrugated GI sheet. We were burglarized twice last year. The burglars were able to break into my 3-storey building by cutting a small portion of the corrugated GI roof. Hence, to obviate any future “break in” , I decided to have a concrete roof.

    I’ll keep you posted on any development with regards to my use of Super Thoroseal on my roof deck as a waterproofing product

  27. james says:

    Hello, We have a basement with a sump pump in it. The pump is in a corner and in a recessed hole in the floor. (concreted hole) There seems to be 4 1″ pipes coming in from different sides. water pours into the pump and it pumps it out no problem. But we get water in from other areas of the basement. The floor is no pitched to the pump so this water gets 2 to 3 inches deep in places. We clean the water out and in about a hour it has started to come back in. It doen’t pure in BUt if you look close you can see it trickleing in. It’s a cinder block wall on a concrete slab basement. The walls don’t leake at all BUT where the blocks and the wall meet is where we have the problem. My mother-in-law has put Dry-Lock down for years to try and stop it. so there is a little build up at the junction of the wall and floor. Is there anything we can apply or bursh on the will dry and seal while the water is trickling in? Some places it runs faster than others. It takes all night to get 2 to 3 inches deep in an area about 8 feet by 10 feet. Thanks

    • David says:

      Your basement sounds exactly like mine. In my case I couldn’t afford the product to deal with the situation. So I made my own french drain using some 1″ roof edging and a few tubes of high grade construction adhesive, applying both to the joint where the wall and floor meet. Being sure to apply a generous amount of adhesive to the joint and then pushing the drip edge into the joint. I ran it around the basement to the sump pump. While it didn’t completely stop all the water from entering, it’s now down to a trickle. I am continuing to use this until I can afford a more permanent fix.
      I should note too that our basement is fo

  28. Fred says:

    James, it sounds like you have a real challenge here that is beyond what STS or any inside-applied waterproofer is meant to handle. There is obviously a serious external source of water problem that is going to require professional help – potentially the installation of a French drain around the perimeter of the foundation. I recommend getting a professional in to take a look. Unfortunately, with that kind of water coming in and standing, you are likely facing an expensive fix.

  29. Soggy says:

    Thoroseal cannot be applied to a pre-painted surface…which is exactly what I have. Any alternatives?

  30. Fred says:

    Soggy! I love the alias. You have a few options, but none are like Thoroseal. You can try to tackle this from the exterior of the house (which would involve adding drains around the perimeter). You could also install a french drain around the perimeter of the interior of the house. However, in general, I think the best approach for where you are at this point is to call a professional.

  31. Erik Johnson says:

    I appreciate your insight on the Thoroseal questions. I am getting ready to do this project. I’m imagining I should use a cement mixer drill paddle not a paint mixer. I have remove the furring strips that were installed for panelling however the nails are not as cooperative should I just cut the tips?

    I have used concrete and mortar seals to fill cracksin the walls. I carefully removed the floor tiles (asbestos) and sealed it with an oil based primer and two coats of floor paint.

    The grand plan is to install the furring pressure treated furring strips and rigid foam insulation and then cover with green mold resistant drywall that will be painted and then install carpeting.

  32. Fred says:


    1) Drywall paddle is what you want. Paint mixer might work but only if its the right style.

    2) The nails question is a tough one. How many and are you sure they cannot be pulled out? If you could get them all the way flush, I MIGHT cover them over, but I stress the “might” – it would depend on a lot of factors and I’ll bet you wouldn’t get the Thoroseal folks to agree its the right thing. I don’t think there’s any particular reason it wouldn’t work, except that you could have a weak spot in the bond.

    3) How are you going to attach the furring strips after you seal? Hopefully not with nails? Have you considered just framing out 1×3 walls about 1 inch off the block/cement? You shouldn’t penetrate the seal once it’s applied.

  33. Erik johnson says:

    how would you suggest anchoring the wall?

  34. dadskills says:

    is there any product that can be applied over a painted cinder block wall?

  35. diana says:

    we applied Thoroseal in our basement about 6 years ago. we noticed recently that in one area it is “flaking” off if you brush it with your hand, don’t kow the cause of this, the area is quite large. was wondering, can we recoat over the “old” Thoroseal to cover up the area that has flaked? there are “black” areas where the Thoroseal has flaked off.

    • Fred says:

      Can’t pass judgment in your particular situation, but the most likely causes for flaking are:
      1) Surface preparation wasn’t done correctly.
      2) Thoroseal was mixed to the wrong consistency (likely mixed with too much water).
      3) Thoroseal was applied over a painted surface.
      Depending on the reason, you may be able to re-apply. If the problem was just a bad mixture, you should be able to re-coat following all the instructions for an initial coat and you will get a water tight seal.

  36. Vicki says:

    Fred, this is the best info on Thoroseal I can find, so thank you. We had a fireplace built, and have had trouble with dampness on the chimney breast (made of cement or cinder block). Contractor came back today for the third time in as many years and pulled down all the drywall — completely soaked with mold on the back in places. He’s coming to apply Thoroseal tomorrow. Since this fireplace is in the MBR, it will have to be drywalled or plastered, then painted. What is the process for finishing this and eventually painting it?? Thanks so much…

    • Fred says:

      Vicki, I’m not sure what will really “work” but I know that Thoroseal says you cannot paint it on the can. I’ve not tried finishing it… I’m not sure that painting it would necessarily be bad – but I would avoid it just because of the instructions.

      Many times chimney problems are due to poor flashing. Are you sure that Thoroseal is the answer? My parents had big problems for years with a chimney until they got a guy who knew how to properly flash the chimney. Never needed Thoroseal, and I know our chimney on our house doesn’t have it. I would get alternative opinions before committing.

  37. Maryanne Alfano says:

    Fred – Hi! Thanks for your insight, and infor on ThoroSeal. My husband and I have been geeting water in our basement for years, a little at a time, but is now increasing and spreading. It starts in the back boiler room, which is lower than the patio and garden behind our property, and 9′ below the property of the neighbors behind us. We get rain water in the backyard and the rainwater of our neighbor since the original owners put drainage pipes coming out of the retaining wall onto our yard. Water comes in through the seam between the wall and floor, which my husbad mops up (to the tune of 6 pails, usually. However, the water is now working its way toward the fron of the basement coming up through floor tiles. The back wall is wet when it rains (or snow melts) and the wall is flaking – we were recently told that whoever applied paint to that wall made the mistake. We are considering a frencgh drain around the perimeter, and a de-humidifier. Do you recommend sanding down the back painted wall and applying the Thoroseal, then doing a finishing wall in front of it?

    • Fred says:

      Maryanne, your situation sounds a little too “wet” for Thoroseal, in my opinion. You really need to address the major issues creating the water first: poor grading, drainage, etc. If you are getting 6 pales of water in the basement on a good rain, you need to work on other aspects before you go after the wall. Think about where the downspouts drain and try to get the water far away from the house. Figure out ways to route the water. Once you are to the point where the walls are getting damp at most, then Thoroseal could take you the rest of the way. If you don’t fix the source of the problem, with that much water, it’s going to get worse.

      • Maryanne Alfano says:

        Thank you Fred. Your comments, at least, make me feel justified in arranging for the French drain and the de-humidifier. It was in my mind to ‘kill 2 birds with one stone’ so to speak, in the backyard, by directing my downspouts into a rain-gathering system, so that I could keep it out of the ground and use it to water my garden later. You have validated that plan too! Many, many thanks.

  38. Joe says:

    I would never recommend nor would I ever use any Throseal product again. They are really good at answering your pre-sales questions but they will let you hang out to dry if you have a problem after using their product. I used their product as directed yet still got water leakage in my basement. I requested assistance as well as later requesting a refund. All of my requests went unanswered.

  39. HANDYMAN51 says:

    Good information on waterproofing and framing in a wall for finishing. Part of the area I’d like to waterproof is painted, flaking. Is there a product that removes the paint & allows fo effective use of ThroSeal?

  40. Jeff says:

    I have a building that was built in 1945. The block on the basement seems to be a mixture of brick, hollow block mostly I think. I had my nephew use motor mix to fill in every last hole, crack, etc. we could find on the walls. When it rains, the water damp mark goes out 6-14 inches from the bottom of the wall. Looks wet, not that you can actually see water. He put the first coat of Tamaseal which he loves to use and then after that, he is going to use two coats of drylock. I noticed the 1st coat of tamaseal that he put on the wall 2 days ago shows darker spots on the wall that are not completely dry, basically showing you where the most moisture is I suspect. Should you go over it a 2nd time with tamaseal or the 2 coats of drylock after the tamaseal will do the job. I realize that this should help fight the dampness in the basement for about 5-7 yrs. I plan on recoating it in 12 months with another passing of the drylock. Any input or suggestions out there. And yes, I do know that the only way to truly fix the problem is to dig up all around the building. I just don’t have the money for that, so this is the poor mans version of trying to combat this.

    • Fred says:

      Jeff, unfortunately I am not familiar with the Tamaseal product so I can’t answer this one with any kind of authority. If Tamaseal is like Super Thoroseal, then you must use two coats before it is waterproofed, and the dampness on the wall will not hurt it.

  41. Michelle says:

    Hi Fred, What is the recommended way to remove some very old paint from a poured wall? (prior to using Theroseal) I was initially just going to wire and stiff brush the loose stuff, but it appears I need to remove it? If I used a soy gel, would I risk leaving a film behind that would prevent adhesion?
    Thank you!

    • Fred says:

      I’m not sure about soy gel or other thinners / strippers and what their effect would be on the ultimate adhesion of the mix. I would actually recommend reaching out to the folks at Thoro and asking them what they would recommend. You may be able to get away with etching the surface of the paint, I’m just not sure… They always recommend complete removal — I’m not sure what their method is though.

      Best of luck!

  42. Icarus says:

    Good post very valuable information

  43. karen h says:

    really liked yr review and side by side tests, and your follow up – great work!

    I just got thoroseal from HD and was going to seal the chimney exterior with it, but just read that I need to use Acryl-60 to make the TS work right – is A60 necessary if temps are high enough, i.e., can i/did you just mix it with water?


  44. Steve says:

    I’m considering Hydro-seal 75. Were you familiar with Hydro-seal 75 when you did this project? If so, why didn’t you use that? If not, what do you think about that product? Thanks!

  45. Joseph says:

    I just finish the application and so far it looks good and appears to be working on keeping the dampness out of the wall . The wall looks a lot better than before now …

    Do I need to apply cement primer after the thoroseal application or I can just paint the wall ?

  46. Chris says:

    I just found this blog, and am pretty upset. I wish I had found this before my contractor came out yesterday and applied TS to my basement. I am fairly certain he did not first wet or clean the block. Can anything be done? He has not yet applied a second coat. Can a second coat be applied on top, maybe wet the surface first? Please advise. I can’t believe after hiring someone that they would apply incorrectly!

    • Sarah says:

      THANK YOU! This review and subsequent replies are awesome. Thanks so much for posting and letting the comments keep going year after year. SO VALUABLE! Just wish I’d found before i had my basement done.

  47. troy cauldwell says:

    what should I expect to pay per SF for a thoroseal application?

  48. Trisha Seals says:

    We are building a waterfall out of cinder blocks. Plan to using Super Thoroseal for waterproofing. Have looked everywhere but can’t find if it can be applied to green concrete. Thoroseal customer service is not taking phone calls right now. Do you know the answer?

    Thank you for all the info you provide!

  49. Jon says:

    Anybody with experience on how this compares to Zinnser WaterTite mold and mildew proof for water resistance (Zinnser can hold back up to 32 psi)? how about for mold resistance?

  50. Tony DiVecchio says:

    I live on a hillside and I’m handicapped…I hired a contractor who applied Thoroseal on both inside and outside basement walls…(twenty years ago and not one drop of water in the basement)…A few tiny cracks have appeared on the outside wall…Can you reapply both sides with Super Thoroseal??

  51. dennis kulig says:

    Can any of your products be used in waterproofing
    swimming pools- 3ft to 5ft deep ?

    • Fred says:

      They aren’t “our” products. We’re just an independent blog reviewing them. I think the answer, however, is no. these products aren’t really designed for that, though they may work. Typically you’re going to want a swimming pool liner or pond liner for what you’re describing.

  52. Craig says:

    I have a home built in 1880 with a 12ft section of basement wall that is stacked stone with Sandy mortar. Could I use ST to deal it? It’s not wet i just want to deal it. Thanks.

  53. Donna says:

    Blue Max will stick to a painted surface. However the condition of the paint is an important consideration. Any paint that is peeling or flaking will have to be removed to assure a good bond to the wall surface. In addition make sure the wall is completely dry before applying Blue Max by Ames at ACE HARDWARE and other places .

  54. Randee says:

    So, I’ve used a concrete based variant of this product to seal a1200 gallon underground irrigation holding tank. It’s since started to leak again. Would this be a better product to use?

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