Drylok Vs Flex Seal: What’s The Difference?
For a flexible waterproof coating of concrete and masonry, Drylok is your go-to. It creates a breathable barrier that can stand up to some serious hydrostatic pressure. But if you’ve got cracks and holes that need some serious sealing, Flex Seal will stick and ooze its way right into those gaps for targeted leak protection.
Drylok Vs Flex Seal: Specs & Uses
⏰Drying Time
Drylok: 2-3 hours
Flex Seal: Flex Seal will usually dry to the touch within 2 to 3 hours and fully cure in 24 hours.
🆚Key Ingredients
Drylok: Latex polymers, titanium dioxide, zinc oxide, ethylene glycol
Flex Seal: Toulene, mineral spirits, aliphatic solvents, liquefied petroleum gas
🛠️Common Uses
Drylok is Suitable for concrete basement floors with future flooring installation; Can be applied to damp walls; deal for waterproofing and sealing concrete garden ponds after proper surface preparation; effectively seal leaks in stucco walls; coat cement steps and walkways.
Flex Seal is suitable for EPDM rubber roofs; Effective for filling large 1-2″ cracks in driveways; provides waterproofing and adds grip to heavily used decks and patios; You can Combine Flex Shot and Flex Seal Liquid for effective duct sealing.
Technical Info
My Hands-on Test: Drylok
✅Pros: Drylok
Its look and texture are similar to rubber cement (difference between contact cement and rubber cement), and I opted for the clear variant, which dried nice and thin with just a subtle sheen. It’s hardly noticeable on the painted deck. As an extra precaution, I also applied it inside the drain scuppers and on the deck rail flanges.
Easy to Use
Initially, I found it challenging to spread the product around. I had expected it to be something I could pour, but it actually had the consistency of rubber cement. However, I quickly found a solution. I put on some gloves
and spread it where I needed it, which worked much better than using a brush. Now, a month into using it, I can confidently say it’s working great for my application.
A few days later, I put the deck to the test by flooding it, and to my delight, not a drop of water leaked below. In the attached photo, you can see how the water beads up. Drylok provided a cheap and easy fix to a significant problem, making me an instant fan. Although I’m unsure of its long-term durability, even if I have to apply it seasonally, it will be worth it.
Versatility
I ordered four cans of Drylok, and I must say, it works as advertised! It has proven to be incredibly effective in solving the issues I was facing. On my second can now, I’ve discovered the best use for Drylokis to seal the top of exposed wood posts. No longer do I need to worry about the tops wearing down due to the weather. Additionally, I’ve used it to seal a few concrete tree rings with decorative tops, and it even repaired a tear in a fabric cover for my fire ring. The process was simple: I placed a temporary backing behind the tear, painted over it with this product, let it dry, and voila! It was all fixed!
❌Cons: Drylok
One thing to keep in mind is that you can’t paint over this product directly; it requires the use of Kilz paint for painting purposes. You’ll find it in the paint aisle. While it works great for many things, it’s not suitable for an RV roof.
FAQ: Drylok
Q: Can I apply Drylok to a wall that is already wet, or should I use a separate product to address the moisture issue before applying this one? (the wall consistently appears damp)
A: If I recall correctly, when I painted the bottom cellar steps, they were wet, and Drylok seemed to work fine in that situation.
Q: How long should I wait after using Drylok Fast Plug to paint the walls with Drylok Extreme?
A: Personally, I waited 72 hours to ensure everything was as dry as possible. I found other instructions that suggested waiting as little as 8-24 hours, but I wanted to be certain that I wouldn’t trap uncured material under a paint designed to seal moisture without breathing. I can confirm that my approach worked, and I haven’t experienced any issues since.
Q: What type of sprayer gun and tip should I use to apply Drylok?
A: For optimal results, it’s best to use a 3/4 Nap roller. However, if you prefer to use an airless sprayer, you can use a .019 tip.
Q: Can I use this to waterproof wood?
A: I used it on concrete, so I’m not sure about its effectiveness on wood.
Q: I already have Drylok oil-based around my foundation. Will UGL latex waterproofing adhere to it?
A: Generally, mixing oil and latex isn’t the ideal solution. I strongly recommend sourcing an oil-based product since you don’t want to risk failure or having to redo the application. Sometimes you can find smaller cans of oil-based paint, even in states that have banned it. Alternatively, you can search online or visit different stores until you find one that can ship to your state.
Q: Can this be used to seal leaking stucco on the side of a house?
A: It’s likely possible, but you need to first locate the source of the water or leak and address that. Otherwise, the moisture or water will find another path if it can’t penetrate the stucco. You can also use the elastomeric silicone sealant 
Q: Can Drylok be used for exterior stucco walls?
A: Yes, it can. For maximum effectiveness, I would recommend applying at least two coats or using Elastopatch. Here is how to use elastopatch.
Q: Does Drylok Extreme come in 5-gallon buckets?
A: Yes, it does, but you can only find them at retail outlets.
Q: Will it effectively seal and hold water in a concrete garden pond?
A: Yes, it should work as long as you properly prepare the concrete. It’s designed to do the job!
Q: Could I use this to waterproof my painted chimney and fill small cracks in the mortar?
A: I don’t foresee any issues as long as the chimney is clean, dry, and the paint isn’t flaking or deteriorating.
Q: Can Drylok be tinted, or do I need to paint over it? I want to use it as a replacement for the liner in a small water feature made of concrete blocks.
A: I used it to coat a concrete pond, and I tinted it using a standard tinting color. It turned out beautifully.
Q: I have a fish pond made of concrete. Is Drylok safe for the fish?
A: I’m not sure about its impact on fish. It would be best to contact DryLok directly for their advice on this matter.
Q: I need to seal 170 sq. ft. of concrete as a sub-floor. How many gallons of Drylok Extreme would I require?
A: Please refer to the directions provided, but generally, less than 2 gallons should be sufficient.
Q: Has anyone used Drylok to paint an in-ground pool?
A: Yes, it has been used successfully. I personally employed it on my skimmer, and it worked well.
Q: Can Drylok be used on RV roofs?
A: No, Drylok is specifically formulated for concrete and masonry surfaces. Since an RV roof is likely made of metal or aluminum, I would recommend using a high-quality elastomeric roof coating, which you can find at most home improvement stores.
Q: Is it possible to use this paint to coat cement steps and a walkway?
A: Technically, you can use it for that purpose, but it’s important to note that its primary function is to water seal concrete. It may not hold up well under heavy abrasion from foot traffic. Instead, I would suggest considering a cement seal that stains the concrete. It lasts longer, is easier to apply, and is more forgiving of imperfections and mistakes.
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My Hands-on Test: Flex Seal Liquid
✅Pros
I also used Flex Seal to patch a leak in a galvanized wash tub, which constantly has water in it. After six months, there has been no sign of any leaks.
Flex Seal Liquid on RV
Make sure you clean the top and don’t have rain roof must be dry before doing the roof or will leave openings or air pockets
Drying Time
In the past, I’ve had incredible success using Flex Seal for various repairs. For instance, I used it to fix the roof of an old RV and repair a leaky car port. However, I had never tested it on an aluminum bird bath before. The drying time was quite lengthy, with the first coat taking over 48 hours to dry, even though I kept it in a warm place. The second, lighter coat took a little over 24 hours. It’s important to allow ample time for drying. Additionally, make sure to stir the can, even if it doesn’t seem necessary. Despite the longer drying time, my project was a success, as it sealed an 8″ crack perfectly, restoring my antique birdbath to full functionality.
Weatherproof Outdoor Furniture
Here’s a fun fact: you can use Flex Seal to weatherproof outdoor furniture. I even used it to weatherproof a pool table. It goes on smoothly and maintains a shiny finish. However, be aware that it does take several days to dry. While I’m unsure about its long-term durability on something like a pool table, it worked well for my initial application.
Easy to Use
I found it easy to use. The coverage is precise, at 18.75 square feet. I recently painted decking boards measuring 60″ x 5.5″, which required a total of 8 boards. I recommend using a disposable brush
, as the paint stiffens quickly. I used a 2″ all-purpose polyester brush that cost $2.99. Depending on the length of your project, you might need a spare brush, as the paint can become inflexible if left for too long. I’ve attempted to clean a brush before, but it was challenging to remove all the product. Avoid using foam disposable brushes, as they don’t work well. I tried using two foam brushes for one quarter of a board, and they quickly became heavy and crumbled, making a huge mess. However, despite my mishaps with brushes, the paint remains usable if properly sealed in the can.
Low Temperature
I have used Flex Seal on the wrong type of wood before, and after four months, there was no mold or rotting. Flex Seal Liquid held up exactly as advertised. I’ve even applied it in temperatures as low as 45 degrees Fahrenheit without any issues. I made sure to paint both the front and back of the wood to prevent future replacements.
❌Cons
Even after Flex Seal has dried, it can still leave a sticky, oily residue on your hands. Once fully cured, it develops a rubbery texture that can prevent objects from sliding smoothly on its surface. This characteristic may not be suitable for all applications, so it’s important to consider the specific needs of your project before using it.
FAQ
Q: Can Flex Seal be applied on EPDM rubber roofs?
A: Many customers have successfully used Flex Seal Liquid for various applications, including EPDM rubber roofs. It is also suitable for use on a wide range of surfaces such as concrete, glass, brick, stucco, masonry, wood, copper, plastic, tile, fabrics, wires, vinyl, fiberglass, ceramic, porcelain, metal, aluminum, natural stones, foam, asphalt, EIFS, TPO, PVC, EPDM, CSPE, Hypalon polyurethanes, and more!
Q: Is it suitable for filling large 1-2″ cracks in a driveway?
A: Absolutely!
Q: Can I apply it to a heavily used back deck or patio? Will it hold up against constant scraping from patio furniture?
A: Yes, Flex Seal Liquid works wonderfully on back decks and patios. It provides effective waterproofing and adds a bit of grip to the surface. Just ensure that you allow it to dry for 24-48 hours before placing furniture back on it.
Q: What temperatures are ideal for roof application? I need to seal a leak, and the temperatures here are dropping. Thanks.
A: For roof application, it is best to apply Flex Seal Liquid when temperatures are above freezing.
Q: Can Flex Seal be used in tires?
A: While customers have found innovative uses for Flex Seal Products beyond their intended applications, Flex Seal Liquid is not specifically designed for high-pressure applications like tires. We do not recommend using it for this purpose. Additionally, it is not recommended for underfoot applications where the surface may come in contact with water, as it may become slippery when wet. Thank you for your interest in the Flex Seal Family of Products.
Q: Will Flex Seal work on pavers?
A: I’m not familiar with pavers specifically, but before making a purchase, please read the compatibility instructions. I have personally used Flex Seal to repair a toilet tank that had multiple leaks, and it worked exceptionally well. After applying a thick layer every 24 hours for three days, the tank was completely sealed, and there were no more leaks. The toilet now functions perfectly, although it still retains its antique charm.
Q: Can it be used to seal leaky ducts?
A: That’s a great question! Yes, you can use Flex Seal Liquid for sealing leaky ducts. Some customers have found success by combining Flex Shot and Flex Seal Liquid for this type of repair. First, apply Flex Shot to fill any gaps or seams around the vents, and then apply 2-3 coats of Flex Seal Liquid over it. Allow approximately 24-48 hours for it to fully dry and create a weatherproof seal.
Q: Does Flex Seal come in white?
A: Certainly! Flex Seal Liquid is available in four fantastic colors: White, Black, Gray, and Clear. If you have any further inquiries, please don’t hesitate to reach out to us. Have a fantastic day filled with Flex-tacular experiences!
Q: Will it seal pressed wood?
A: While I haven’t personally used it on pressed wood, I can attest that it seals concrete better than any other product I’ve tried.
I’m Ronald Stevens, a Mechanical Engineer obsessed with adhesives, glue, and all things sticky! My passion began in childhood when I’d always be the one playing with glue during arts and crafts. And I’d spend hours researching and experimenting. Happy reading, and remember: stick with the best, and you’ll never be stuck in a mess!
Will Drylok be effective in waterproofing concrete basement floors? We plan to install flooring on top eventually.
Absolutely, it can work as long as you intend to cover it with something. However, it's not specifically designed for foot traffic on floors. It performs exceptionally well on walls, providing approximately 10 years of protection in basement applications.
Can Flex Seal withstand high temperatures? I need to seal wood that will be exposed to extreme heat.
Flex Seal Liquid is designed to withstand normal environmental temperatures. However, it is not recommended for use in extremely high-temperature conditions.