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The main purpose of guttering is to channel rainwater away from the home and prevent it from damaging the foundation or seeping into the basement. During installation, rain gutter end caps and seams are coated with a flexible sealant designed to withstand hot and cold weather and moderate impacts. However, the gutters themselves are subject to all kinds of harsh conditions, which, combined with aging, could inevitably cause them to leak.
Several effective approaches to fixing rain gutter leaks and plenty of different gutter sealants are available to consumers. However, gutter styles and materials vary considerably. What works well on vinyl, for example, may not be as effective on galvanized steel, aluminum, or copper. Plus, different kinds of damage require different repair techniques. One product may work better for pinholes or cracks, while another product may be required for a separated end cap.
As a result, we decided to test a variety of gutter installation and repair products, including exterior caulks, tapes, and roof sealants. They differ significantly in application methods and curing times, but each one is capable of creating a watertight seal on vinyl, PVC, and metal gutters. Whether your project involves new gutter installation or repairs and maintenance of old rain gutters, one of the following best gutter sealants available today will be able to handle the task.
- BEST OVERALL: Geocel 2320 Tripolymer Gutter and Narrow Seam Sealant
- BEST BANG FOR THE BUCK: Amerimax SeamerMate Gutter Sealant
- BEST FOR LEAKS: Liquid Rubber Waterproof Sealant
- BEST QUICK FIX: Gorilla Waterproof Patch & Seal Tape
- BEST MULTISURFACE: OSI Quad Max Clear Paintable Sealant
- BEST FOR METAL GUTTERS: GE Metal Silicone 2 Sealant
- BEST SPRAY: Rust-Oleum LeakSeal Spray
- BEST TAPE: XFasten Super Waterproof Aluminum Butyl Tape
- ALSO CONSIDER: Flex Seal Spray-On Liquid Rubber Sealant
How We Tested the Best Gutter Sealants
We simulated gutter installation and gutter leak repairs in our tests and evaluated how each product performed on aluminum and PVC gutters. Using salvaged sections of aluminum and PVC gutters, we first drilled a series of ⅛-inch and ¼-inch holes in the gutter bottoms and applied the sealant product to repair the holes. Then, we used each product to install gutter end caps on both gutter types.
Throughout testing, we made sure to strictly follow the manufacturer’s instructions for each sealant. During the application process, we noted both whether the product was clean or messy to use and how easy or difficult it was to clean up afterward. We also noted the number of applications required, the cure time for each application, the total cure time, and overall durability. After we completed all applications and installations, we filled the gutters with water, observed the water level for 12 hours, and noted any leaks. Finally, we scored each gutter sealant on a scale of 1 to 5 for ease of application, ease of cleanup, quick results, and durability.
Our Top Picks
Our top picks feature a selection of the best gutter sealants on the market. We took into account each product’s effectiveness, value, and environmental impact. While each gutter sealant is a quality product, read on to discover which one may best suit your particular needs.
Best Overall
Geocel 2320 Tripolymer Gutter and Narrow Seam Sealant
Pros
- Adheres to all types of rain gutters, even when wet or oily
- Flows deep into gaps and seams
- Works at any temperature and in all weather conditions
- Seals narrow seams, gaps, and holes up to ¼ inch by ¼ inch
- Cures to a tough, rubberlike finish
Cons
- Emits a strong chemical odor while curing
- Full cure takes up to 5 days
Our Ratings: Application 4/5; Cleanup 4/5: Cure Time 3/5; Durability 5/5
Product Specs
- Application: Caulking gun
- Gutter material: All
- Dry time: 5 days
Building professionals use Geocel 2320 tripolymer sealant because it’s durable and takes the guesswork out of gutter installation and repair projects. It adheres to all types of material, works in any weather, and fills gaps up to ¼ inch in diameter. The self-leveling formula flows deep into the gaps and cures to form a tough yet flexible bond. Each 10-ounce tube contains enough product to extrude a ¼-inch bead of sealant up to 28 feet, using a standard caulking gun. Our tests proved the efficacy of the Geocel 2320 sealant. After loading it in the caulking gun, we squeezed a few small beads of the sealant into the holes we had drilled in the bottom of the gutter, then installed two end caps. This product adhered to anything it contacted, including concrete and wood as well as the gutter materials. It was easy to control the pressure and prevent messes via the dripless feature on the caulking gun. Even though our initial finish was not perfect, the self-leveling texture allowed the ridges and bumps to settle into a fairly smooth finish. The only downside to this product was the cure time. Although a surface skin began to form within an hour, it was extremely pliable for 24 hours. However, after the 5-day cure time, the sealant was very sturdy, puncture-resistant, and fully waterproof.
Get the Geocel gutter sealant at Amazon.
Best Bang For The Buck
Amerimax SeamerMate Gutter Sealant
Pros
- Semi self-leveling sealant makes it easy for DIYers to achieve professional results
- Ultraviolet (UV)-, temperature-, and weather-resistant sealant for all metal rain gutters
- Quality gutter sealant at an affordable price
Cons
- Full cure takes up to 5 days
- Cannot reseal tube to store unused product for an extended period
Our Ratings: Application 4/5; Cleanup 4/5; Cure Time 3/5; Durability 5/5
Product Specs
- Application: Caulking gun
- Gutter material: Metal
- Dry time: 5 days
The Amerimax SeamerMate gutter sealant is a high-quality tripolymer product for metal gutters. Be aware that it is designed to bond metal to metal and may damage other gutter materials. Applied with a caulking gun, the self-leveling formula fills gaps and holes up to ¼ inch and leaves a smooth, tough finish. This sealant is designed for secure gutter installation and repairs that can withstand harsh weather for decades. One of the most affordable gutter sealants we tested, Amerimax SeamerMate was easy to apply, easy to clean up, and formed an incredibly strong bond. Our drip-free caulking gun helped prevent messes.
The product’s self-leveling consistency delivered professional-looking results, and it was paintable the day after application. Although we preferred the final results of the Amerimax SeamerMate over most of the other products, the slow cure time of up to 5 days might be problematic for some users. Also, for a single small repair, the full 10-ounce tube could be excessive, and there is no way to reseal it for later use once you’ve opened it. Still, this sealant is a great product at a great price, best for midsize and larger repairs.
Get the Amerimax gutter sealant at The Home Depot or Ace Hardware.
Best For Leaks
Liquid Rubber Waterproof Sealant – Multi-Surface Leak
Pros
- Easily bridges seams, gaps, and small holes over a broad area
- Excellent adhesion and flexibility for flat or shaped vertical or horizontal surfaces
- Remains flexible and durable and will not degrade from sun exposure
- Contains no volatile organic compounds (VOCs) or solvents and emits no harmful odors
Cons
- Relatively slow drying time
- Can require more than 1 coat
Our Ratings: Application 4/5; Cleanup 3/5; Cure Time 4/5; Durability 4/5
Product Specs
- Application: Brush, roller, or piston sprayer
- Gutter material: All
- Dry time: 24 to 48 hours
While a number of paintable, rubberized gutter sealants on the market are very effective, many are unfortunately solvent-based. Water-based Liquid Rubber sealant has virtually no odor yet all the benefits of its more toxic competitors. You can apply Liquid Rubber with a roller or even a piston sprayer—although the latter requires professional-grade equipment. This product adheres well to both vertical and horizontal surfaces, and the ability to perform without splitting or cracking means it will flex as much as necessary without compromising adhesion. Liquid Rubber is UV-stable, so the sun’s harmful rays won’t damage it.
Depending on the size of the repair, it may need two coats, and a slow drying time means it can take several days to fully complete the repair. In our tests, the first coat felt dry after 12 hours, but we waited the full 24 hours before applying another coat. In all, we applied three coats over the ⅛-inch and ¼-inch holes in the bottoms of our gutters, but two coats would have been adequate. We filled the gutter with water 2 days after the last application, and it held fast. You can paint over this sealant once it’s fully dry.
Get the Liquid Rubber gutter sealant at Amazon or Lowe’s.
Best Value
Gorilla Waterproof Patch & Seal Tape
Pros
- Easy to cut to shape, peel the backing, and cover the seam for an almost instant repair
- Withstands freezing, high temperatures, UV light, and abrasion
- Adheres to prepared surfaces underwater if the surface is properly prepared
- Multipurpose; also works for a variety of wet and dry applications
Cons
- Nearly impossible to reposition once the adhesive contacts the repair surface
- Difficult to remove the tape backing and cut to shape in cold weather
Our Ratings: Application 3/5; Cleanup 5/5; Cure Time 5/5; Durability 4/5
Product Specs
- Application: By hand
- Gutter material: All
- Dry time: Instant
Gorilla waterproof tape provides a durable repair virtually immediately. It is 4 inches wide—a good size for substantial cracks or splits—and is one of the best ways to seal gutter seams. The adhesive grip is very effective on all gutter materials. This product is UV-resistant and can withstand temperatures as low as -70 degrees Fahrenheit up to 200 degrees Fahrenheit. Each roll is 10 feet long, and it will store almost indefinitely in an airtight bag at room temperature.
Although the manufacturer states that you can apply Gorilla tape to wet surfaces, our tests revealed that only dry surfaces work well. The surface also needs to be sound: The tape will lift if the surface is dusty, flaking, or slimy. We had to cut the tape to fit with the backing still in place; otherwise, the tape stuck to the knife or scissors and was very difficult to remove. It’s also important to use caution while positioning the tape. Once we placed the tape, it was nearly impossible to remove.
One downside is that the Gorilla tape didn’t blend well with the gutter surface. The thick profile of the tape stood out, as did the pure white color against the patina of our 50-year-old gutters. Additionally, this product is not paintable and so is best used on the inside of the gutter, if possible, to hide the repair.
Get the Gorilla gutter sealant at Amazon, The Home Depot, or Walmart.
Best Multi-surface
OSI Quad Max Clear Paintable Sealant
Pros
- Fast acting; paintable in 1 hour and full cure in as little as 24 hours
- Versatile product for gutter installation and repairs, flashing, windows, doors, siding, and trim
- Adheres to most building materials, including metal, plastic, masonry, and glass
- Enhanced resistance to UV rays, dirt, dust, and extreme temperatures
Cons
- More expensive compared to other several high-quality options
- Sets up faster than competing products, so cleanup must be addressed promptly
Our Ratings: Application 4/5; Cleanup 4/5; Cure Time 4/5; Durability 5/5
Product Specs
- Application: Caulking gun
- Gutter material: All
- Dry time: 24 to 72 hours
Primarily labeled as a window, siding, and door sealant, OSI Quad Max is also highly rated for gutter sealant applications. It has a higher viscosity than other gutter sealants to allow for faster setup and creates a tough watertight bond that stands up to UV rays, dust, dirt, and extreme weather. This product is an excellent choice if you need to keep a project moving quickly, as it is paintable within an hour and cures fully in as little as 24 hours. During our tests, we noted stiffer resistance on the caulking gun while applying OSI Quad Max sealant compared to most of the other gutter-tested products.
This sealant is also less forgiving of sloppy work. Since it isn’t a self-leveling sealant, it didn’t flow downward into the voids quite as thoroughly, and any imperfections in the bead were likely to remain after curing if we didn’t take the time to smooth them out. However, once cured, our end caps and drilled holes stayed watertight.
Get the OSI Quad Max gutter sealant at Lowe’s or The Home Depot.
Best for Metal Gutters
GE Metal Silicone 2 Sealant
Pros
- Faster setup than most paste-type sealants; waterproof in 30 minutes
- Low-odor silicone caulk is less irritating during application
- Long-term durability and allows for 25 percent joint movement
- Resists mold and mildew growth for 10 years
Cons
- Cures to a softer finish and lower adhesion than tripolymer-type gutter sealants
Our Ratings: Application 4/5; Cleanup 4/5; Cure Time 4/5; Durability 4/5
Product Specs
- Application: Caulking gun
- Gutter material: Aluminum, galvanized steel, copper
- Dry time: 24 hours
While general-purpose products are often capable, specialist alternatives invariably provide a better solution. This GE sealant, for example, is formulated particularly for metals. It is a silicone-based sealant that we applied with great accuracy and economy using a caulking gun during our tests. It flowed easily into gaps, seams, and cracks, and we found the initial drying time to be very rapid. This product is permanently waterproof in around 30 minutes, although a full cure takes 24 hours. The silicone component keeps the sealant flexible, so it will not shrink or crack. It has high UV resistance and can withstand temperatures from -60 degrees Fahrenheit to a staggering 400 degrees Fahrenheit.
Although odor-free once cured, the GE sealant does emit an unpleasant vapor during application, so it’s important to wear a mask during use. It can also irritate the skin, so gloves and eye protection are equally necessary.
Get the GE gutter sealant at Amazon, Lowe’s, The Home Depot, or Walmart.
Best Spray
Rust-Oleum LeakSeal Spray
Pros
- Easy-to-use spray-on formula; works just like spray paint
- Fills gaps up to ¼-inch wide with just 1 or 2 applications
- Several color options from which to choose
Cons
- Highly flammable while spraying
- More difficult to clean up than water-based options
Our Ratings: Application 5/5; Cleanup 4/5; Cure Time 4/5; Durability 3/5
Product Specs
- Application: Spray
- Gutter material: All
- Dry time: 24 hours
Rust-Oleum LeakSeal gutter spray sealant contains butyl rubber, which is known for flexibility and high adhesion. Spraying it on is an easy and convenient way to handle small gutter repairs. This product is dry to the touch in about 30 minutes, and you can apply a second coat, if necessary. For example, it may successfully fill gaps up to ¼-inch wide, but more than one application would be required. The sealant then takes 24 hours to fully cure.
Rust-Oleum LeakSeal is available in five colors and can also be painted over with latex or oil-based paint. In our tests, Rust-Oleum LeakSeal spray went on as easily as advertised, with a tight spray pattern that helped minimize overspray. We used a scrap of cardboard to shield the peripheral area, and it worked well. The sealant filled both the ⅛-inch and ¼-inch holes in a single application, but we added a second coat to increase strength. As with the tape and paint-on products, this spray sealant is not designed for attaching end caps. However, it did a thorough and relatively quick job of patching pinholes and bridging joints.
Get the Rust-Oleum gutter sealant at Amazon, Tractor Supply Co. (black), or Walmart.
Best Tape
XFasten Super Waterproof Aluminum Butyl Tape
Pros
- Creates a watertight seal to repair leaks and gaps in metal, plastic, rubber, and other surfaces
- Aluminum backing is engineered for flexibility and high puncture resistance
- Thick butyl rubber adhesive conforms to fill surface voids and provides maximum contact to textured surfaces
- Resists degradation due to temperature extremes, UV rays, chemical exposure, and other adverse conditions
Cons
- Adhesive can become excessively sticky in warm weather
Our Ratings: Application 4/5; Cleanup 5/5; Cure Time 5/5; Durability 4/5
Product Specs
- Application: By hand
- Gutter material: All
- Dry time: None
Waterproof butyl tape makes gutter repair fast and easy. XFasten aluminum butyl tape has a unique “quilted” backing that allows the tape to conform to textured or uneven surfaces. The thick adhesive side embeds into surface voids for a perfect watertight fit, and the aluminum side is highly puncture-resistant. The roll measures 16 feet long by 4 inches wide and has a 5-year storage life, making it an ideal choice for storage in an emergency repair kit.
To cover our ⅛-inch and ¼-inch holes, we cut ½-inch by ½-inch squares of the XFasten tape. Because the weather was cool and dry, we were easily able to remove the backing and place the adhesive patches over the holes. The tape held water instantly. Next, we added a seam test by overlapping two gutter system sections—the end of one section nested inside the matching end of the other section, overlapping by 4 inches. We taped the seam from the outside, with the XFasten tape centered on the seam. Then, we taped the inside seam the same way. The tape provided a perfectly drip-free seal while strengthening the joint.
The main problem with the XFasten tape was that the sides of the roll, where the adhesive was marginally exposed to air and handling, became extremely sticky. This made the roll more difficult to handle, especially while taping interior seams. Still, the end result was a strong waterproof patch that was ready within seconds instead of hours or days.
Get the XFasten gutter sealant at Amazon.
Also Consider
Flex Seal Spray-On Liquid Rubber Sealant
Pros
- Easy spray-on application and fast drying time for quick, convenient repairs
- Tough, flexible coating resists punctures, abrasion, and joint movement
- Tolerates hot and cold temperatures, without weakening in summer or cracking in winter
Cons
- Requires ambient temperature above 65 degrees Fahrenheit for application
- Not suitable for sealing newly installed seams and end caps
Our Ratings: Application 5/5; Cleanup 4/5; Cure Time 4/5; Durability 3/5
Product Specs
- Application: Spray on
- Gutter material: All
- Dry time: 2 to 3 hours
Flex Seal sealant has been an infomercial staple for years, and it works as advertised for rain gutter and downspout repairs. This rubberlike product goes on like spray paint and becomes a tough, flexible, watertight skin that resists sagging and dripping in hot weather and won’t crack in cold weather. It’s a great choice for quick repairs of leaky seams and pinholes.
Since our testing period was in late November, we took note of one instruction in particular. Flex Seal requires an air temperature of at least 65 degrees Fahrenheit during application, so we performed our testing on a warm afternoon. After applying the first coat, we waited 24 hours before applying a second coat. After another 24 hours, we tested the seal. It worked perfectly on the ⅛-inch and ¼-inch holes as well as the overlapped seam. The gutter was leak-free, and the cured spray showed a fair amount of toughness against attempts at scraping with a paint scraper and puncturing with a finishing nail.
We didn’t love that Flex Seal sealant required mild temperatures for application. However, we did like how easy it was to apply and how effective it was once cured. This product is also useful for a wide range of household projects, so it could be a handy item to have available.
Get the Flex Seal gutter sealant at Amazon (2-pack), The Home Depot, Walmart, or Staples.
Jump to Our Top Picks
What to Consider When Choosing a Gutter Sealant
There are several considerations to keep in mind when choosing a gutter sealant. While the gutter material is a key factor, the position and type of leak can also impact your selection. Prevailing weather conditions, curing time, and the flexibility of the final seal also play a part. Here are the characteristics that the best gutter sealants have in common—as well as what might make one product better for a particular job than another.
Type
Before discerning between types of sealants, it’s important to recognize that caulk and sealant are different products. Caulk usually comes in a tube, which you apply using a caulking gun. Acrylic caulks are water-based and paintable, but they lack the flexibility of sealants. As a result, they are more prone to cracking—particularly under wide temperature fluctuations—so avoid using acrylic caulks to seal gutters.
The best rain gutter sealant can be either water- or solvent-based. Some of the latter emit a strong odor and can be irritating to the skin, eyes, and nasal passages, so be sure to wear gloves, eye protection, and a mask during use.
Different sealants can vary considerably:
- Paste sealants most closely resemble caulks. Often silicone-based, they are frequently used for aluminum and other metal gutters.
- Liquid rubber sealants are versatile, water-based, multisurface products applied with a brush or a roller.
- Spray-on sealants apply quickly and easily over small areas. They are often similar in composition to liquid rubber sealants, though they tend to be more expensive.
- Sealant tapes are another rapid adhesion, multisurface solution. Some sealant tapes may be less durable than other types of sealants.
Adhesion Strength and Surface
How well a particular sealant adheres to the gutter material is clearly of major importance. Most gutters are made of vinyl or aluminum, but some gutters are constructed of galvanized steel, zinc, or copper. Certain sealants may not stick to particular surfaces, and while general-purpose sealants can be versatile, no single product is the best gutter sealant for all materials. Thus, it’s vital to check compatibility. Failure to do so may mean a temporary fix, but adhesion strength will be compromised and the leak might soon reappear.
No matter the gutter material, preparation will be key. Nearly all of the best gutter sealant reviews emphasize the need to follow the manufacturer’s instructions carefully, and we echo that advice: It’s essential to read and follow directions to avoid failure of the repair.
Dry Time, Flexibility, and Durability
Gutter sealants can require anywhere from under an hour to up to several days to dry completely. That can be a big difference if there’s only a short time window for the repair, especially if you also need to paint the gutter.
Generally speaking, a degree of flexibility in a sealant is beneficial because gutters are subject to movement from wind and temperature changes. Flexibility can also impact the durability of the fix. It’s not only about surviving freezing temperatures but also the wide range of temperatures a repair may have to endure depending on the part of the country in which you live. Metal gutters in areas that experience extreme fluctuation in weather conditions can be particularly challenging because of how much they will expand and contract.
It’s worth considering a sealant that contains UV inhibitors, which give increased protection against the harmful effects of the sun’s rays. Chemical resistance can also be beneficial. Salt, for instance, can be a problem for homes in coastal areas.
Versatility
Numerous products are designed to seal gutters and nothing else. Shoppers can purchase other products, however, for various coating and repair purposes—from sealing around window frames to fixing holes in pool liners. If you only have a modest gutter repair, it may be economical to purchase a versatile sealant that could come in handy later for another home improvement project.
Still, be sure to check shelf life before investing in a large can of multipurpose sealant: Some of these products have a limited useful lifespan once opened. In these cases, a sealant might work well for gutter repair now, but when a different task arises in a few months, it might have hardened and become useless.
Tips for Using Gutter Sealants
As noted above, remember to follow the manufacturer’s instructions as closely as possible for any gutter sealant you purchase. In terms of basic advice, the following tips should help ensure a successful gutter repair.
- Cleaning gutters once every 6 months will help identify damage early on and allow for repairs before major problems arise.
- Try to only apply a gutter sealant on top of existing repairs or surfaces that are damp in an emergency. Ideally, the gutter should be clean, dry, and free of any previous product.
- Ensure that the sealant thoroughly penetrates cracks and seams rather than just lying on the surface.
- If the joint in need of repair will not hold together on its own, apply clamps or binding while the sealant cures. Depending on the product, curing can take several days.
- While gutter sealants can be very effective and often handle large repairs, there are limits. Sometimes, the best solution is to replace a section of the gutter.
FAQs
The gutter material, prevailing weather conditions, and the type of sealant all impact longevity. If applied carefully while paying close attention to the manufacturer’s instructions, a gutter sealant should last at least several years. Extreme cold or heat can reduce that time, but a careful product choice can maximize durability.
Use a caulk and sealant remover like Krud Kutter, mineral spirits, or lacquer thinner to remove old gutter sealant. Apply sparingly, allow it to soak in, and then lift with a putty knife or a chisel. Apply more remover if needed and wipe with a rag until you have a smooth, clean surface.
Some polyurethane sealants are safe to apply while moisture is present, though it is generally recommended to only seal gutters when they are dry. However, depending on the temperature, waiting 2 to 3 hours after the rain stops to apply sealant should be safe.
It depends on the product, so check the manufacturer’s instructions. Keep in mind that no type of gutter sealant should have prolonged contact with the skin, so it’s best to wear gloves. In particular, nitrile work gloves are reasonably tough yet thin enough not to restrict your movements.
Meet the Tester
Mark Wolfe is a writer with an extensive background in the green industry and an avid DIYer who lives in a 50-year-old home. When he isn’t writing, he spends his time upgrading, repairing, and replacing anything and everything in his home, yard, and garden. He tests and writes reviews about hand tools, lawn care and home repair products, and outdoor living goods.
Additional research provided by Bob Beacham.
