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Roof sealants not only cover roof leaks, but they also provide a protective layer to prevent water and sunlight penetration. These sealants come in many forms, including liquid in a paint can, liquid in a spray can, liquid in a caulk gun, and adhesive tape. They’re also made of a variety of materials, including silicone, rubber, and polyurethane.
Choosing the best roof leak sealant to help you patch up a roof leak can depend on several factors, such as the size of the seal and the type of your roof. You can expect to spend between $20-$50 on most individual sealant packs. However, sealants sold in larger quantities for whole-roof sealing can cost upwards of $150-$200. After researching over 20 of the best roof sealants available and reading hundreds of customer reviews, our pick for the best sealant for small roof leaks is Dicor Self-Leveling Lap Sealant, which come in an easy-to-apply tubes, while our pick for larger leaks is Liquid Rubber’s Waterproof Sealant. Read our guide below for more of our top picks.
Best Sealant for Roof Leaks: Our Top 5 Picks
- Best Overall: Dicor Self-Leveling Lap Sealant
- Best for Large Leaks: Liquid Rubber Waterproof Sealant
- Best for Minor Leaks: Flex Seal Liquid Rubber in a Can
- Best Tape: Gorilla Waterproof Patch & Seal Tape
- Easiest Application: Flex Seal Spray Rubber Sealant Coating
Best Overall
Dicor Self-Leveling Lap Sealant
Good For: Homeowners who need to fill a small seal quickly on roofs or other areas of their home.
What Are People Saying About the Dicor Self-Leveling Lap Sealant?
We found that customers who gave this sealant a positive review liked that it was long-lasting and had an easy application. Several others complimented its self-leveling ability. However, we found that some others felt this product had cheap packaging, and others said it bubbled up instead of sealing flat on their roof.
“Use to seal cracks and screw heads on RV roofs. Have used for 20 years, quality product, Shipped quickly, liked the price. I usually, order 12 at a time. Never been disappointed in the results.” — Roger W. Stone via Amazon
“Was such a good price for a popular product but after using four tubes, it made our TPO roof bubble up where ever it was put. That was put on over a week ago, and it has not been laid down all the way yet hoped it will when it gets warmer.” — Sarah Boneham via Amazon
Best for Large Leaks
Liquid Rubber Waterproof Sealant
- $200
Prices taken at time of publishing.
Good For: Customers who need a large amount of sealer for large leaks or whole-roof projects.
What Are People Saying About the Liquid Rubber Waterproof Sealant?
We noted that many reviewers who liked this product commented on its ability to dry quickly and how easy it was to apply to rooftops. Others said that it was particularly good at getting through tight cracks. However, some others said that it didn’t work well on wood, and others said it leaked easily.
“This is sort of a liquid rubber as you apply it out of the bucket. Consider it thicker than paint, but still ‘paintable’ in application. I really like it because it will ooze into all the cracks and nooks and crannies that you want to be filled without making you aggravated doing it. Then it settles and flattens out really nicely. Once completed, your roof will be sealed.” — NE Major Dude via Amazon
“I just received my item, and I’m sure the product itself is great. However, the bucket leaked during shipping, so I’m unsure just yet if the product has cured at all due to lack of sealing.” — Emily via Amazon
Best for Minor Leaks
Flex Seal Liquid Rubber in a Can
Good For: Those looking for a non-toxic easy-to-apply sealer for small or minor roof leak repairs.
What Are People Saying About the Flex Seal Liquid Rubber in a Can?
We found customers who left positive reviews for this product liked its thick coating and long-lasting, water-tight seal. Others liked that it However, numerous customers said this sealer was messy and leaked easily.
“I used it to reseal the joints and seams of an aluminum-vinyl type roof on a sunroom that is 15 years old. It looks professional and is watertight; any roofing company would have charged a lot for this project…. There are not too many products that live up to what they say they do, but this product does! It works great, and the flex glue also is a winner.” — Amazon Customer via Amazon
“It works very well as a sealant, but it’s very messy, hard to clean off the brushes and will get messed up if air hits it in the can. You have to use mineral spirits to clean it up or off.” — Ms. SDS via Amazon
Best Tape
Gorilla Waterproof Patch & Seal Tape
Good For: Customers looking for a quick-fix sealer to patch up areas and keep them protected from water damage.
What are people saying about the Gorilla Waterproof Patch & Seal Tape?
For this product, we found that many of the positive reviews centered around the strong adhesive and user-friendly design. Others were impressed by its ability to stick on wet surfaces. On the other hand, several other customers felt this tape didn’t hold up to heavy precipitation, and others said it was difficult to use.
“Sticks to nearly anything wet or dry. Even underwater. I use it to repair spots on my RV’s roof. Have had some on there for nearly a year now with no signs of coming off. One thing about this tape is that you need to make sure you place it exactly where you want it because it isn’t coming off without one hell of a fight. Extremely pleased with this tape.” — Bocephus193 via Amazon
“I found this extremely difficult to use. You get a very short length with this rool. You have to peel a piece of paper off of one side it’s extremely sticky and difficult to use. I bought it to keep a living room rug in place on top of a larger rug but it didn’t work for me.” — WHH via Amazon
Easiest Application
Flex Seal Spray Rubber Sealant Coating
and vulnerable edges, because of its small size.
Good For: Homeowners who prefer a spray sealer that can handle small or medium-size roof repairs.
What Are People Saying About the Flex Seal Spray Rubber Sealant Coating?
Several customers we found were pleased with this sealer’s strong seal, noting it held up to wind and rain. Others liked how simple it was to apply and how versatile it was to use on various parts of the home. However, some others said it did not stay in place and others said it had a strong smell that took several days to go away.
“I live in high plains with tons of high wind. Some of my shingles started getting loose and flapping. Before it turned into a full-blown leak I decided to buy these cans and some shingles to replace the crap ones…. The Flex-Seal actually stuck the new shingle to the roof a bit, making it so the wind has less of a chance of blowing it up now. It’s been about a month since I replaced the shingles, and so far, so good. I bought the two-can pack but didn’t need the second one since the one can has a lot of coverage.” — MJ Castle via Amazon
“I used this both to seal a retaining wall over a newly repaired (by a contractor) foundation and to fix a leak in my large, free-standing waterfall. So far, no problems! Make sure you ventilate!! Very strong chemical smell, which dissipates within a few hours. You simply cannot stay in the same room as the spray for several hours, even with windows open.” — Debra50 via Amazon
Types of Roof Sealants
Typically, roof sealants are separated into five categories based on what they’re made of, including:
Acrylic
Acrylic sealants are designed to deflect UV rays, making them popular in the South and West where roof sun damage is common. They also have a moderate amount of moisture resistance, making them best for sloped roofs because flat roofs tend to create pools of water that acrylic isn’t strong enough to withstand.
Polyurethane
Polyurethane sealant is highly resistant to water but not as resistant to sunlight, making it best for areas that get a lot of rain and snow as opposed to sunshine.
Silicone
Silicon-based sealants offer both water and sunlight protection, making them good for protecting your roof from any weather condition. The main downside to this type of sealant is that it’s expensive, preventing it from being financially feasible for homeowners on a budget to buy enough of it to cover their entire roof.
Rubber
This type of sealant comes as a liquid form of rubber. It’s usually water-based to thin the rubber and make it easier to apply. It protects against both sun and rain.
Tape
While most other options are liquid, this type of sealant comes as strips of moisture-resistant material. It has an adhesive backing that you stick onto the roof to stop leaks or seal seams. It’s an affordable sealant option, but because of its small size, it’s not meant to cover an entire roof.
Buying Guide
Each roof sealant will vary in terms of water resistance, UV reflectivity, longevity, and application. It’s important to take all of these factors into consideration before choosing the best product for your needs. Read our buyer’s guide below to find our more information on selecting the best roof-leak sealant.
What sealants have the best water resistance?
Every sealant provides some level of water resistance, but rubber, silicone, and polyurethane have a waterproof quality, allowing your covered roof to withstand heavy rain and standing water. However, in order to create a completely waterproof barrier, your sealant will require several layers. Its directions will instruct you on how to do this.
What should you look for to determine a sealants UV reflectivity?
A sealant that can reflect sunlight helps to keep your house cool. This is especially useful in the summer months, as it can decrease air conditioning use and result in a lower electricity bill. Rubber, acrylic, and silicone sealants have the highest reflectivity levels. The color of the applied sealant will also play a role in its reflectivity, with lighter colors being better at reflecting than darker colors.
How long lasting is the average roof sealant?
Each sealant has a varying lifespan, but most last 10-20 years. Tape sealants last this long with one layer of tape, but the remaining liquid types may require several coats, as a thicker coating lasts longer. Proper application is another factor that affects longevity. If you don’t follow the manufacturer’s instructions, you’ll decrease the sealant’s life. Most manufacturers warn against applying their sealant in cold weather, to a wet or dirty roof, or before a storm when it hasn’t had enough time to cure.
What is the process like for applying roof sealant?
Different sealants have different application methods. The tape type of sealant has a self-explanatory application process, but the remaining types may come in a paint can, spray can, or caulk tube. The paint can method gives you a thick layer of sealant along with the quantity to apply it to a large surface area. Spray cans and caulk guns take less work, but they come in smaller quantities, making them best for small leaks.
How to Identify a Roof Leak
Finding a roof leak that needs treatment is the first step before narrowing down your sealant options and helping you avoid the cost of a new roof. There are several tell-tale signs that can help you identify roof leaks, both from inside your home and from the roof. Read this guide below for some common roof problems.
- Water on the ceiling: The most common sign that you have a leak is a wet spot on the ceiling. If you can access your attic, check the area above the leak and see if there are more leaks or wet insulation.
- Musty smell or Dripping Sound: If you can’t visibly see a roof leak appearing on your ceiling, but still hear a consistent dripping sound or smell musty odors, it may still be the cause of a roof leak. This should also prompt a trip to the attic or on the roof to help you find the exact source of the leak.
- Vent boot needs to be replaced: Rubber boots around plumbing vents can sometimes tear or crack, which can cause a leak. If you notice a tear in the boot, try to replace it with a new boot and see if that solves the leaking issue.
- Damaged shingles: If you’re looking at your roof and see damaged shingles, that could be a tell-tale sign of a leak and should warrant further inspection.
- Pooling water: If your roof has pools of water after a rainstorm that doesn’t evaporate in 48 hours, it could lead to a leak and should be treated immediately.
- Mold or mildew: If you notice mold or mildew seeping into your home, it means water is leaking into your home, and it’s likely coming from the roof. At the first sign of mold, inspect the attic as soon as possible.
Frequently Asked Questions
What does the ISO certification on my roof sealant mean?
The International Organization for Standardization (ISO) created standards for testing how well a sealant protects a surface from corrosive elements. The scale ranges from C1 to C5, with C1 offering minimal protection and C5 offering maximal protection. It’s up to you to determine how much protection you want your sealant to offer, but if you live in an area with harsh conditions, we recommend looking into a C5 sealant.
Can you remove roof sealant?
Yes. You can remove liquid sealant with a plastic putty knife if you’re looking to DIY. If you’re having trouble peeling your tape sealant off with your hands, you can also use a putty knife. However, be careful not to damage the shingles underneath.
How long does it take for a roof coating to dry?
It depends on the sealant’s formula and the weather at the time of application, but most liquid sealants will take between eight and 24 hours to dry.
What is the difference between solvent-based and water-based roof sealants?
Solvent-based sealants are highly resistant to the elements, but they’re more expensive and take more effort to apply because of their thick consistency and requirement of wearing a respirator. Water-based sealants are less resistant to the elements, degrading faster and requiring more frequent touch-ups. However, they’re more cost-effective and easier to apply.
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