SunnyDry Concrete and Masonry Foundation Waterproofer Sealer Review

July 3, 2008 | by Fred (email) |

About one year ago we applied Wall Firma’s SunnyDry Foundation Waterproofer to seal more than 500 sq ft. of mostly below-grade cement block in our basement.  Our goal in applying SunnyDry’s Sealer was two-fold: (1) to eliminate a small amount of water seeping through the block and pooling near the base of the exterior walls, and (2) to eliminate dampness on the block and reduce overall humidity in the room.

We applied a competitors’ product, Thoro Company’s Super Thoroseal, to a different 500 sq. ft. of below-grade wall space in the basement.  This review focuses soley on our experience with SunnyDry.  Super Thoroseal is reviewed separately, at that link. In the picture here, Sunny Dry is gray, and Super Thoroseal is white.  The wood studs sitting in front of the wall are anchored at the top and bottom of room, and are not anchored to the block walls (this would compromise the waterproof seal).

Selection Reasons and Overall Evaluation

We chose SunnyDry for its economical price, its 10-year guarantee to stop water and dampness in below-grade applications, and its relative ease of application over other types of waterproofing methods (trenching and sealing from the exterior, installing a french drain inside, etc).

Overall, we are extremely pleased with the results.  SunnyDry’s Foundation Waterproofer completely sealed the basement walls.  We’ve had no water seep through the block; the walls aren’t even damp.  Humidity in the room is substantially reduced.

Purchase Information & Price

We purchased SunnyDry Concrete Waterproofer from our local Lowes in 60lb. “contractor size” buckets for $28.98 each (2007 price).  The sealer is gray, both in powder form and when it’s dry on the walls.  The dull color isn’t particularly important in our application–our walls will eventually be drywalled–it only serves to distinguish the area of the wall covered by SunnyDry’s Waterproofer from the area covered by Super Thoroseal.

Applications for the Waterproofer Beyond Below-Grade Walls

SunnyDry is a a portland cement-based powder waterproofer designed to seal exterior below-grade walls.  Wall Firma advertises that their product will work on concrete, brick, stone, or masonry.  Our review is limited to concrete block.  While not applicable to our application, SunnyDry can also be used in potable water installations (e.g. drinking water tanks), bird baths, fish ponds, fountains, and pools.  If we ever build a fountain, they’re top on our list to seal the inside.

How Portland Cement-based Waterproofers Work

SunnyDry’s sealer has chemicals in it that, when activated with water, react and subsequently dry to a water tight seal.  The Waterproofer actually seeps into the pores in the concrete block and keep water trapped behind the block.  Super Thoroseal claims their product will stand up to 200PSI of water pressure.  Wall Firma makes no PSI claim on their Foundation Waterproofer.  For comparison, most latex-based waterproofers that you “paint on” seal walls to approximately 20 PSI.  I assume that, based on the technology employed in Super Thoroseal and SunnyDry, SunnyDry has a similar waterproofing capability.  In our situation, we have french drains built into the exterior front of the house that drain to the rear, so we don’t have a pressure build-up concern.

Foundation Waterproofer Preparation Experience

Overall, preparation was relatively easy, but a bit time consuming.  SunnyDry recommends four steps to prepare the walls for applying the waterproofer:

  1. Clean the surface of the block with a wire brush to remove any loose mortar, paint, or dust on the walls.  We didn’t have a wire brush handy, but our walls had never been painted, and were covered with insulation ever since the house was built.  There was very little, if any, loose mortar to deal with, so we skipped this step.
  2. Remove any efflorescence using Sunny Dry Concrete Cleaner or a mild acid.  We used a competitor’s product available at Home Depot, which sufficed just fine.  Essentially, the acid we purchased is mixed with water and sprayed using a pump sprayer.  After application, hose down the walls and vaccuum up the excess water.
  3. Plug any large holes, cracks, or active water leaks with a quick drying hydraulic cement.  Sunny Dry recommends their Hydraulic Leak Stop Cement.  We had no large cracks or leaks, so we skipped this step.
  4. Dampen the walls with regular water using a pump sprayer or garden hose.  We highly recommend using a hose, as a pump sprayer simply doesn’t put enough water on the walls.  You want the walls to actually be damp during application.  It ensures the block doesn’t absorb the water out of the waterproofer too quickly, and as a bonus, it makes SunnyDry easier to spread.  You will need to repeat this step throughout application, so run the hose inside.

Foundation Waterproofer Application Experience

Applying the sealer is relatively simple, but very tedious.  In a nutshell, applying SunnyDry boils down to a few easy steps:

  1. Mix the powder with several quarts of water;  use a wire-frame style mixing blade to mix.  Add powder until the mix reaches a mildy thick pancake batter-like consistency.  Note that Wall Firma says you can use a paint mixer.  I highly suggest going with a drywall mud mixing blade, as some paint mixers like the “the squirrel” available at home depot, will clog.  Drywall mixing blades are available at the big box.
  2. Dampen the walls.  We used a hose and found this to be a very good method.
  3. Spread SunnyDry using a Tampico-fiber brush, starting at the top of the wall and working down.

Coating & Coverage Experience

SunnyDry recommends two coats in order to obtain the best waterproofing performance.  We found this true.  After one coat, we still had some water seeping through the wall.  After the second coat, the dampness was eliminated.  We actually applied a third coat, something SunnyDry indicates may be necessary at the base of walls or in tough-to-waterproof spots.  We did it because we’re paranoid about future leaks.

SunnyDry claims 265-340 sq. ft. of coverage for the first coat on porous surfaces and up to 440 sq. ft. on second coats and non-porous surfaces. We found their claim to be spot-on. It took us approximately five 60lb. buckets to cover our 700 sq. ft. area with three coats.

Final Thoughts

After 12 months of use, many products have left us wanting more – a feeling that we really didn’t get what we paid for.  SunnyDry Foundation Waterproofer has left us feeling just the opposite.  We’re extremely pleased with the results, and 1 year later, we’re enjoying a dry, relatively low-humidity basement space.  Way to go, SunnyDry!

What do you think? Have you had a good experience with a basement waterproofing product?

37 Responses
  1. Nicole says:

    Hmmm … sounds like a great product. I’m just a bit concerned about the effects — if any — on the color. If it dries gray like that, I’m thinking it would darken all my bricks.

    Will be looking to seal my new brick porch and walkway later this summer so your timing on this couldn’t be better!

  2. Fred says:

    Nicole — This product is completely opaque – not a clear sealer that you would apply to brick that will remain visible on an exterior or finish interior room. The difference being that this is a permanent waterproofing solution, where as the brick sealer you would use on a porch and walkway is actually a temporary sealer that will wear off after several years. (SunnyDry is guaranteed to prevent leaks for 10 years).

  3. Todd says:

    Sounds like a great product. I’d argue there’s NO WAY they can maintain 200 psi!! However, using a portland cement based product is definitely the way to go. Portland cement reacts with water and hydrates to create a very strong bond to other portland cement products (block, concrete, etc). The big problem with sealing from the inside is it’s like trying to plug a dam, it’s much more effective to do from the outside. I’m glad it has taken care of your small water problem.

  4. Fred says:

    Todd- I wish there were a way we could test this easily to determine whether Super Thoroseal meets its claim of withstanding 200psi (note, just for clarification, that SunnyDry never makes suchs a claim).

    And, you’re right about plugging from the inside being a challenge. In most cases, giving this stuff a shot first is the easiest solution. If it proves to hold tight for a good period of time, you get to save all the money/work associated with “fixing it right.”

  5. Todd says:

    My take is it’s impossible. Maybe from the outside and most likely that’s where their claim comes from. The other argument/reasoning they may be using is that most tensile strengths of concrete are about 10% of the compressive strength. So…if you say the stuff has a compressive strength of 2000 psi then maybe you can say it has a tensile strength of 200 psi. At any rate it at least is working for you so that’s great. I tell people that these paints/sealers are a great second line of defense and a great way to keep out small amounts of moisture.

  6. Josh says:

    I’ve got a couple places where something like this could be very helpful. Thanks for the review, Fred. I’m looking forward to the follow up on Thoroseal.

  7. Dixie Scheiderer says:

    We have a farmstead cheese making facility. SunnyDri was used in 2003 to plaster all the interior walls of a 60×30 block building and a 28,000 gal. block water supply cistern built and Sunny Dri covered in 1998. We have been EXTREEMLY pleased with the results. The interior walls of the facility are washed everyday and of course the cistern is wet and holding a lot of water. BOTH structures meet FDA regulations and have remained bright white[non yellowing], non stained even with chlorine and chemical use. We are now finishing our 2nd farm cheese facility and will guarantee SunnyDri will be on all outside surfaces including the milking parlor. The first facility is in Ohio[now owned by our son] and our second one is in Kentucky and will be named Kentucky Farm Cheese. This building is a remodel of an existing block building that had been painted but last year we put the Sunny Dri over a small painted wall against the weather to test it. It has been washed, frozen, super heated in summer , chlorined and is still super hard and white. The rest of the building is to be done this week. Next is the block foundation of our new home. NOW THERE! That makes us all feel good… sure could use more Sunny Dri

  8. aaron oberster says:

    Where’s the Thoroseal review? Been more than another year now. Both still holding up?

  9. kevin says:

    I can not find this product on the shelves anymore ?

  10. Andy Cohen says:

    I applied Sunny Dry as per instructions. Everything seemed to go OK.
    Now 2 days later the area is “weeping”. I’m guessing that the moisture
    I’m seeing bleeding from the treatment is water. Is this normal? How
    long before the treated surface will be dry. We’ve had no rain for weeks
    hence the “weeping” liquid is not external water coming through the wall.

  11. Daniel Jordan says:

    Where can I find Sunnydry products ?

  12. Fred says:

    SunnyDry products are available at Lowes.

  13. G says:

    Thanks for the review Fred. I’ve been doing some research on how to seal my basement to bring down the humidity and can’t decide which way to go.

    I read that the paint on sealers can be pushed off the surface by hydrostatic pressure and start to flake and crack, but they are cheaper.

    Did you consider any of the silicate sealers? The premise is that they penetrate deep into the concrete and seal it internally by reacting with lime and alkalis. The silicate mineral seals the gaps permanently. They supposedly bond, strengthen, and waterproof concrete and stop efflorescence.

  14. Fred says:

    G – We didn’t look into other options such as a silicate sealer. That said, my understanding is that SuperThoroseal and SunnyDry work the same way you describe here…. by bonding with the cement and closing the pours.

    Super Thoroseal claims a 200 PSI waterproofing capability… That’s about 10X the typical paint-on sealer’s claim.

  15. Matt says:

    Do you know of a waterproofing product that I can apply to the exterior (below grade) concrete block basement?

    I have a finished basement and the cost to tear everything out….

    I am going to dig up the outside and attach the leaking problem from there.

    Any advice would be greatly appreciated.



  16. Chuck says:

    I’m presently in the process of applying SunnyDry on my basement walls. The walls are hideous looking and SunnyDry has completely transformed the look. Since my house is nearly 100 years old and there was flaking paint (I am using proper procedures to remove as much paint as feasable) I still have some old color bleeding causing some spots to show through. I have already applied 2-3 coats and am wondering if I could paint the walls? This would also soften the very rough texture.


  17. Chuck says:

    I’ve answered my own question about painting over SunnyDry. I applied a coat of white masonry paint and it looks fantastic. The surface is smoother and not as rough.

    One problem that I would like to point out is when applying over a painted surface, make sure you use at least a 50/50 solution of their acrylic bonding liquid and water. I used the minimum and found out the hard way that it didn’t stay adhered to the wall. It came off in big sheets. I redid the bad sections with the 50/50 solution and everything seems to be ok now.


  18. Laura says:

    I did a lot of research on Sunny Dry. My husband and I were concerned about one wall in our basement that stays wet right where the air conditioner discharges the water outside. We tried attaching a pipe to the existing pipe to get the water farther away from the house, but it didn’t seem to help, so we decided to attack it from the inside. We bought on 60# bucket of Sunny Dry and also the hydraulic cement. The walls are not very old and don’t have cracks or anything, but there were some small areas of effloresence. I didn’t get the acid cleaner, but used bleach instead, and I did not rinse the walls afterward/ I applied the hydraulic cement as directed, and a couple weeks have passed. The spots are looking like the cement is not going to seal. They are darker. We haven’t put the waterproofing solution on because I am afraid that we will be wasting our time. Could I just go over the spots with the correct acid product and then rinse as directed, then re-apply the hydraulic cement? Or…is it too late to do anything about it? It has been frustrating. Thanks!

  19. Fred says:

    Laura, I would definitely clean off the effloresence and then apply the sunnydry after that. I’m not 100% sure I understand. Did you cover the effloresence with the hydraulic cement?

  20. Laura says:

    Yes, I did cover the effloresence with the hydraulic cement. I am not sure whether I did the right thing BEFORE I covered the effloresence with the cement. I did not use the acid recommended on the efflorescence. I used bleach, and do not know if that took care of the efflorescence. By the way, what is efflorescence?! What I mean is, is it a mold? Salt deposits, what?
    I have another question for you about the waterproofing, but want to get the answer to this one first. Thanks!!! Laura

  21. Fred says:

    Hi Laura, Efflorescence is salt. See here:

  22. Chris says:

    Im a new general contractor here in Ohio, Ive gotten a order to do a basement that is made of cinder block. I took care of cracks and gaps with Hydralic Cement and Cement Caulk. I cleaned all the walls down with soap, mildew/mold removed and bleach. Then went around and scraped the entire wall (even the good spots) with a wire brush to make the painted surfaces and non painted surfaces rough. I used the Addition chemical it said to use to make it bond to painted walls… However I didnt apply any water at all to the first coat on the first wall (havent gotten any further) and its really grainy paint like Stucco paint. Has anyone else had that feeling or look? I got the “White” 60lb buckets.

    • Fred says:

      Chris, are you using the powder or a paint-on substance? You said, “I didn’t apply any water at all to the first coat on the first wall”…

      If you are using the powder, it should go on this but I wouldn’t describe it as stucco paint / sandy when it goes on.

  23. James says:


    I have a cinder-block basement garage which you drive down into. It looks like it has had a gray-sealant on previous years that has now failed.

    On one side, the wall is completed underground and was growing mold as well as having white salt deposits. It also had patches that were cold and damp (when I scrubbed with a wire brush, I actually got splashed from the water coming through).

    I sprayed it with bleach to kill the mold, and scrubbed the white deposits with a wire brush (until there was no loose/raised debris).

    Then I dampened the wall all over and applied a first thick coat of sunnydry (white powder).

    However, all the patches that were previously damp are still damp and are a light gray color instead of white. It has been 4 days since I applied the first coat. The sunnydry doesnt come off when i touch it, so maybe it has hardened?, but it is an odd salty/fluffy texture. Is this normal?

    How come it hasn’t turned white and stopped the water? Is it just that the first coat still has areas the water can seep through and it will be fixed when I apply the next 2 coats?

    Thanks, James

    • Fred says:

      James, I’ve got a few concerns about your story:

      1) The wall needs to be completely stripped of any existing paint product before applying SunnyDry. The only exception, I think, would be of the product that was on before was a cement-based waterproofer.

      2) SunnyDry is only waterproof after two coats, and those coats must be applied within 24 hours of each other, if I remember correctly. This is because you really want the cure to happen slowly and create a full bond.

      3) The wall should be etched to remove flourescence. It sounds like you did that.

      4) The sunnydry will have a rough texture, but it should not flake off at all. If you are getting sandy/dust coming off the wall, you likely did not mix the material to the right proportions.

      Up in my “Related Content” section there is a review of Super Thoroseal. That may be a good second resource for you to review.

      I know that leaky basements and garages can be frustrating … Let me know if I can help any more.

    • Fred says:

      James, I should have added that you should have used an etching product. Look in the related content section above for a link to Wall Firma’s etching product. The efflourescence on the wall could prevent a good bond. I think from where you are now, you will have to do a minimum of two more coats. Definitely read the super thoroseal article. Hopefully you are mixing this stuff with a drill paddle.

  24. Daniel Perlmutter says:

    how can I color the powdered Sunnydry product?

  25. Brent says:

    Fred, I searched the internet on information about sunnydry, and your page here was the best written and most descriptive information out there. You have helped me make my mind up that this is what I am going to use. I just wanted to say thank you for putting all your time and effort into writing this and anwsering everyones questions.

  26. ranch-burger says:

    Would this be a product that you would use under carpet? Just removed the carpet in several rooms and noticed some small cracks that need to be sealed as well as some effevessance and funky smell. The previous owner had not graded the yard properly, allowing for some moisture issues – so before I lay new carpet, I want to make sure everything is sealed up properly

  27. Mickey says:

    Hi Fred,
    Great post as usual. Wish I had happened upon it sooner. In any event, if you are still receiving comments on this, I do have a question for you. My concrete block basement has been painted with a masonry paint sealer called Fostex 40 I believe (similar to Quickrete, but was supposedly more industrial with mold treatment). Short of sand blasting, there doesn’t seem to be an easy (or price-effective) way to remove this paint (I’ve tried wire brushing it and it doesn’t come off). Nevertheless, we still get effervescence coming through in several areas. I know the product you describe requires that we remove the paint, but I was wondering if there is anything you’d recommend that we could apply over the paint? For instance, what if we sprayfoamed the walls? Besides providing insulation, do you think foam would also act as a reliable water-proofer? Any other ideas? Thanks for your thoughts (and anyone else who responds to this).

  28. Will says:

    I have cinder block walls in my basement with high humidity during the summer from water vapor escape into the basement, leading to the typical musty basement smell. I do not have any water seepage – the blocks are dry to the touch. I intend to insulate with closed-cell foam. Closed cell foam is a water and a vapor barrier. How important is it to first apply SunnyDry (or equivalent) waterproof coating to the cinder block walls, before the closed-cell foam, as you describe in your video?

  29. Todd says:

    Can you go through the steps for applying to basement walls again?

  30. greg says:

    I have heard good stuff but also can’t find this product anywhere. I have seepage three my walls and water in basement. Would like to do this before spring rain

    • jhnwmaliani says:

      I have the same problem,they had in in stock @lowes but not anymore
      have e-mailed the co. wall firm but never get any response.i have a feeling that it is only sold retail to contractors,and that they have to apply it

  31. Johnny says:

    I appreciate what you said about adding coats. If there is only one coat, there is a good possibility of a leak, with additional coats that likely hood decreases. We recently had a leak that ruined part of our wall. It has left us a little paranoid about future leaks as well. Its better to worry about preventing then to worry about taking care of the damage.

  32. Daniel Boyle says:

    I used Sunny Dry back in the late 70s when it was available in colors, (I used a yellow/gold color), and was awed by the results. I used it on the inside of block basement walls that at one place had a spring oozing water through. When dry, the water no longer came into the basement and the walls had a finished appearance. Damp and moisture free! (The area where the spring perpetrated dried with a glossy finish, compared to the rest being flat, but another coat could have created a match. I didn’t care about the gloss, as it was my laundry room area. Sold home 11 years later with a beautiful dry basement.

  33. john d baxter says:

    used sunny dry 10 years ago .where can i buy it now around rochester new york

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