The 7 Best Roof Sealants for Lasting Repairs, Tested
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Avoid expensive roof damage by repairing gaps and preventing leaks with these tested roof sealants.
Roofs are designed to withstand an impressive onslaught of extreme weather, but daily exposure to sun, rain, hail, or snow can eventually degrade even the toughest roofs. The small leaks and weakened sections that form can let in moisture that may result in the need for expensive repairs, or even a new roof.
By filling little gaps and damaged sections with a sealant, DIYers can make protecting and repairing a roof an easier and more affordable task. While some products are meant for small and isolated leaks, others are designed to create a virtually impenetrable barrier over the entire roof. If you need to repair your roof or extend its life, keep reading to learn how we chose the seven best roof sealants for various roofing materials. After putting these picks through 2 weeks of hands-on testing, we have tangible insight to give on each one’s pros, cons, and best uses.
- BEST OVERALL: Liquid Rubber Waterproof Sealant
- BEST BANG FOR THE BUCK: Gorilla Waterproof Patch & Seal Tape
- BEST FOR LEAKS: Liquid Rubber Peel & Stick Seam Tape
- BEST FOR RV ROOFS: Liquid Rubber RV Roof Coating
- BEST FOR FLAT ROOFS: Rubberseal Liquid Rubber Waterproofing
- BEST FOR METAL ROOFS: Liquid Rubber Color Waterproof Sealant
- BEST FOR FLASHING: Loctite PL Roof and Flashing Polyurethane Sealant
How We Tested the Best Roof Sealants
We wanted to ensure that we were suggesting only the best roofing sealants because a mistake here could leave us (and our readers) all wet. After reviewing popular and well-reviewed options, we ordered seven top sealants and put them to the test. Since we had a roofing project coming up, it was the perfect opportunity to take some of these products for a spin.
First, we wanted to test how difficult each product was to apply. We followed the manufacturer’s instructions (most recommend three coats), applying the sealants to our roof as well as a sheet of sheathing for side-by-side comparisons. To test the tapes and caulk, we covered some gaps we created between scrap boards and left them out in the rain and snow.
At the end of the 2-week test period, we scored each product and gave it an award based on performance. Overall, these products do exactly as they claim: create effective barriers against moisture and seal gaps.
Our Top Picks
To make selecting an appropriate sealant easier, we tested the following top picks and categorized them by roof type or need. Since all of these products proved themselves to be capable waterproofers that work as the manufacturer suggests, we considered ease of application, odor, and value when determining which roofing sealants were best.
Best Overall
Liquid Rubber Waterproof Sealant
Photo: istock.com
Product Specs
- Type: Water-based polymer
- Amount: 1 quart, 1 gallon, 5 gallons
- Application: Brush, roller, or sprayer
Pros
- Thicker than most of the other sealants we tested, so it’s better for larger gaps or cracks
- Blends in well if users sprinkle some shingle grit on top
- Adhered very well to plywood and shingle surfaces during our tests
Cons
- Consistency might be a little too thick for some sprayers
Regardless of the roof material or the climate, Liquid Rubber’s sealant is designed to protect. It’s capable of creating a waterproof membrane on metal, shingle, or rubber roofs that are either flat or sloped. The rubber coating this sealant creates is so resilient against standing water that it can be used on the bottom of planter boxes or gutters; thus, it can certainly protect a roof from rain or snow. This sealant is also ultraviolet (UV) resistant to help shield a roof from aggressive sun exposure.
During our test, we found Liquid Rubber waterproof sealant to be the most dependable. It’s thicker than many other materials, so it’s great for filling in gaps or larger cracks as well as creating a good barrier in one coat. It’s also the most “blendable” of the products we tested, allowing us to hide a repair on a black asphalt roof with a bit of roofing grit sprinkled on top. It adheres very well to plywood and asphalt, but because it’s thicker, it may need to be thinned to be sprayed, which can affect its durability and elastic properties.
Get the Liquid Rubber waterproof roof sealant at Amazon, Lowe’s, Walmart, or Liquid Rubber.
Best Bang for the Buck
Gorilla Waterproof Patch & Seal Tape
Photo: amazon.com
Product Specs
- Type: Tape
- Amount: 10 feet
- Application: Manual
Pros
- Very easy to apply; simply requires cutting, peeling, and sticking
- Much thicker and far more adhesive than duct tape
- Application surfaces don’t have to be dry, making it an excellent choice for emergencies
Cons
- Users only get 1 chance to apply it without bubbles, which takes time and attention
For those who need to repair only a small section of roofing and don’t want to purchase an entire container of liquid sealant, Gorilla’s 10-foot roll of seal tape is a solid, budget-friendly option. This waterproof tape creates a permanent bond that can patch a leak on a variety of roofing materials, including metal, rubber, plastic, and wood. While it works best if applied on a warm and dry day, it can also be used during cold, hot, humid, and wet weather. It can even be used underwater; however, it’s not designed to patch asphalt shingles and may not stick to a roof already treated with a liquid sealant or other water-repellent material.
During our test, the Gorilla waterproof tape was easy to apply, requiring us to simply cut, peel, and stick it. But we quickly realized we only had one chance to get it on without bubbles—it cannot be repositioned once it’s attached. The tape is thick and durable (much thicker and gooier than a piece of duct tape), but the adhesive is so strong that it can damage the material underneath it. Its strong adhesive ability means users can apply it underwater or on wet surfaces, making it an excellent choice for emergency repairs.
Get the Gorilla roof sealant at Amazon, Lowe’s, Ace Hardware, The Home Depot, or Walmart.
Best for Leaks
Liquid Rubber Peel & Stick Seam Tape
Photo: istock.com
Product Specs
- Type: Tape
- Amount: 50 feet long by 2 or 4 inches wide
- Application: Manual
Pros
- Can be used to repair a leak or as flashing tape when applying sealant on top
- Adhesive is very strong, allowing it to stick securely to a variety of materials
- Creates a structural bond when combined with roofing sealant
Cons
- Somewhat expensive for the amount of tape received; other products will be a better value for larger areas
- Has to be combined with roofing sealant for the intended bond
To prevent small roof leaks from creating expensive damage down the road, Liquid Rubber’s seal tape can quickly and easily seal leaks on a variety of roofing materials. This seal tape comes in 2- or 4-inch-wide strips with an adhesive backing that sticks to metal, shingles, and rubber. It can be applied without additional tools and doesn’t require any surface protection or cleanup.
After testing, we almost removed this tape from our list. While it’s great at what it does, there are some caveats users will want to understand. For one, it has to be coated with an additional roofing sealant to be protected from UV rays. Also, it’s relatively expensive for the amount of tape received. But if users know how to use it, it’s a superior product: It can serve as a leak repair tape or flashing, and the adhesive is extremely strong. It created a structural bond between the boards we sealed together, likely due to the mesh backing and its absorbing the roofing sealant.
Get the Liquid Rubber roof sealant tape at Amazon, Lowe’s, or Liquid Rubber.
Best for RV Roofs
Liquid Rubber RV Roof Coating
Photo: istock.com
Product Specs
- Type: Polyurethane
- Amount: 1 quart, 1 gallon, or 5 gallons
- Application: Brush, roller, or sprayer
Pros
- Thinner material can be sprayed without diluting with water
- 5-gallon drum provides enough material for multiple coats to most RV roofs
- Flexible compound won’t crack; can withstand the RV driving on bumpy, uneven roads
Cons
- Requires a primer coat to be applied to the roofing surface first
A leaky RV roof can quickly cause extensive damage to the RV’s interior, but Liquid Rubber’s roof coating is specifically formulated to protect against this costly problem. It creates a waterproof and UV-resistant rubber coating over an RV’s rubber or metal roof, which should keep it cool during the summer and protect it from weather damage year-round.
The rubberized membrane has a high level of flexibility, making it perfectly suited for the constant movement of an RV. One 5-gallon container is enough to provide two to three coats on an RV up to 30 feet long, so users may only need a single bucket to seal the entire roof. For users who only need to cover existing leaks or cover vulnerable seams, this sealant is also available in 1-quart and 1-gallon containers.
Liquid Rubber’s RV coating is thinner than almost all the other roofing sealants we tested, meaning users can spray it without clogging their sprayers. However, it’s important to note that this sealant requires a primer, so while one 5-gallon bucket can cover an entire RV roof, users must prime the roof first. Since it’s a highly flexible sealant, it’s a great choice for withstanding the rigors of driving along bumpy and uneven roads.
Get the Liquid Rubber RV roof sealant at Amazon, Lowe’s, or Liquid Rubber.
Best for Flat Roofs
Rubberseal Liquid Rubber Waterproofing
Photo: amazon.com
Product Specs
- Type: Liquid rubber
- Amount: 1 quart, 1 gallon, 2 gallons, or 5 gallons
- Application: Brush, roller, or sprayer
Pros
- Material is thin enough to spray without diluting with water
- Emits a very low (if any) odor during application
- Reflects UV rays to keep surfaces cool; Energy Star certified
Cons
- Doesn’t feel quite as elastic as the other roofing sealants we tested
Flat roofs are particularly susceptible to damage caused by water seeping inside leaks or cracks, and preventing issues caused by pooling water on flat roofs is where Rubberseal’s roof seal really stands out. It provides a protective membrane that’s moisture-resistant and virtually impenetrable to standing water while also possessing high solar reflectivity to keep a roof cool and protected all summer long.
Rubberseal offers this sealant in several colors, including white, black, light gray, and dark gray, to suit different aesthetic preferences and UV-resistance needs. We didn’t have a way to time-collapse and intensify the sun’s damage on this roofing sealant during our test, but the white version we tested certainly appeared to reflect the sun and stay cooler than other sealants. Its thick, solvent-based formula is easy to apply with a paint roller or brush; we also found it thin enough to spray. It had minimal odor, and we liked that it didn’t require a primer. Our only complaint is that it didn’t feel quite as flexible as some of the other compounds.
Get the Rubberseal roof sealant at Amazon, The Home Depot, or Rubberseal.
Best for Metal Roofs
Liquid Rubber Color Waterproof Sealant
Photo: istock.com
Product Specs
- Type: Liquid rubber
- Amount: 1 gallon, 5 gallons
- Application: Brush, roller, or sprayer
Pros
- Thinner and easier to apply than the base waterproofing sealant from the same brand
- Available in multiple colors so users can give their roof a fresh look
- Adheres well to plywood and is just as difficult to remove as the standard sealant
Cons
- Thinning it may affect its color and make it hard to replicate
For a sealant specifically formulated for metal roofs, this option from Liquid Rubber is hard to beat. The water-based formula can be applied with a brush, roller, or sprayer, and it dries into a moisture- and UV-resistant thick rubber membrane. The waterproof barrier it creates is resilient against pooling water, so it can be used on flat roofs as well as sloped.
We expected this product to be exactly the same as the waterproofing sealant from Liquid Rubber, but it was thinner and easier to apply, though just as difficult to remove. We liked that it’s available in multiple colors (our test bucket was white and very bright), which will please folks looking to give their metal-roofed buildings a fresh new look. This sealant’s specialized nature gives it an edge on metal roofs, but it can also be used on concrete and wood. Note that applying it in thin layers affects the color, which makes it harder to replicate.
Get the Liquid Rubber color roof sealant at Amazon,