Best Caulk for Gutters 2021 – Reviews and Buying Guide

There’s a gutter leak you need to seal off. Before you grab the first brand of caulk you come across, you need to make sure you get the right one for the job, or else you’ll be right back at it in a couple of weeks.

Not all gutter repair sealants are created equal. Some are designed to adhere to metal surfaces, while others just work on plastic. Then there’s the rare kind that works on metal, plastic, and a host of other material substrates. Now those are the superheroes of the caulk nation.

We tested various sealants that came highly rated by professionals and DIY gurus to bring you our top picks for the best caulk for gutters.

Loctite PL S30 CaulkSashco 14010 CaulkDAP Polyurethane Caulk
Best OverallBest Versatile OptionBest Industrial Grade Option


10 oz.10.5 oz.10.1 oz.



Compatible with

Plastic, metalPlastic, metal, wood, concrete, asphaltPlastic, metal, wood, concrete

Waterproof /

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How We Tested and Compared These Products

The first thing we looked at was the label. That’s right. Certain brands can’t let you down even if they try. We’re talking – Loctite, Sashco, and DAP. These three companies have a proven track record of excellence and high quality in the construction market. Their products are a testament to their expertise.

The next thing we weren’t going to compromise on was the materials they were compatible with. We wanted a caulking product that works on both metal gutters like aluminum and plastic gutters. We wanted something we could use more than once for different applications around the home.

We also tested both clear and black sealants. While their performance was not based on color, we did find clear caulk more versatile. We wanted products that delivered a smooth finish blended seamlessly with the material substrate we applied them to and were paintable.

Since we were going to use the products on a gutter, they needed to be waterproof and weatherproof. Anything that cracked in extremely hot or cold conditions, such as silicone caulk and rubber sealant, was automatically eliminated from our list.

Our Pick: Loctite PL S30 Caulk – Best Overall

Loctite PL S30 Black Roof




  • Size: 10 oz.
  • Color: Black
  • Compatible with: Plastic and metal gutter
  • Weatherproof: Yes

Loctite PL S30 polyurethane is the go-to gutter sealant for most professionals and DIYers. If you’re looking for reliable, long-lasting, industrial-grade caulk, this is your best bet. The company is one of the leading producers of adhesives and surface treatments and has grown to become one of the most trusted brands in the country.

If you need to fix a leak in your gutter, the PL S30 is precisely what you need for the job. It forms a permanent, waterproof seal in any exterior gutter joint or roof seam. Many of the products we tested and rejected were marketed as weatherproof and waterproof sealant caulks, only to find they were not. The PL S30 held up remarkably well even in extreme outdoor conditions.

The best thing about it has to be its ability to stay flexible. It expands and contracts along with the aluminum gutter without compromising the integrity of the original seal. It exhibits outstanding corrosion resistance, flexibility, and tear resistance. You would be surprised by how hard it is to find products with these features.

It has a low Volatile Organic Compound (VOC) formula, making it safe for indoor applications as well. All in all, we were quite pleased with this particular brand of caulk. It is a worthwhile addition to your construction arsenal.

  • Has ozone and UV resistance to remain flexible with sun exposure, unlike silicone caulk or rubber sealant
  • Weatherproof and waterproof
  • It is paintable and blends seamlessly with the material you apply it on
  • Low VOC formula
  • Tear and corrosion resistant
  • It might not be effective for masonry applications when working with roofing cement
Loctite PL S30 Black Roof and Flashing Sealant 10-Fluid Ounce...
1,959 Reviews
Loctite PL S30 Black Roof and Flashing Sealant 10-Fluid Ounce...
  • Country Of Origin: United States
  • Model Number: 1618181
  • Item Package Dimension: 47.63" L x 47.63" W x 287.5" H


Best Alternatives

Sashco 14010 Caulk – Best Versatile Option

Sashco 14010 Through The Roof Sealant




  • Size:5 oz.
  • Color: Clear
  • Compatible with: Plastic, metal, wood, concrete, asphalt
  • Weatherproof: Yes

Sashco 14010 caulk is another favorite. If you need to fix a leak in your gutter in wet weather conditions, this is the tool you need to get the job done. It is one of the very few sealants on the market that work even in standing water. Naturally, we had to test it to find out whether this was true or just another marketing gimmick. The results were nothing short of impressive.

We took an aluminum bowl and punctured a small hole in it. We used a bit of playdough on the outside of the bowl to temporarily seal it while we filled the bowl with water. The idea was to simulate a crack on the surface of a gutter in wet weather conditions under extreme moisture.

We then proceeded to apply Sashco 14010 on the inside part of the hole while submerged in water. We gave it a few minutes to set and then removed the playdough we had stuck on the outer part of the bowl. There was no leak. We left it standing all day, and still, no leak. The caulk had sealed it off completely.

We were pretty impressed, to say the least. If you ever need to fix a leak in your roof or gutter in the middle of a storm, this is the sealer you need to take up there with you.

It sticks to concrete, wood, metal, plastic, and asphalt and also works well on dry surfaces. It creates an invisible, permanent gutter seal and stays intact even in extreme 0⁰-120⁰F weather. It’s a solid choice overall.

  • Fast-acting gutter sealant even in standing water common in the downspout
  • Compatible with a wide range of materials, unlike silicone caulk or rubber sealant
  • Ideal for wet and dry surfaces, including those with rust
  • Forms an invisible, permanent, paintable seal
  • Excellent elasticity even in extreme temperatures
  • This gutter sealer isn’t as durable on tile flashing
Sashco - 14010 Through The Roof Sealant, 10.5 oz Cartridge, Clear...
379 Reviews
Sashco - 14010 Through The Roof Sealant, 10.5 oz Cartridge, Clear...
  • Adhesives, Sealants & Patching/Caulk & Sealants


DAP Polyurethane Gutter Caulk – Best Industrial Grade Gutter Sealant

Polyurethane Construction Adhesive and Sealant




  • Size:1 oz.
  • Color: Black
  • Compatible with: Plastic, metal, wood, concrete
  • Weatherproof: Yes

If you’re looking for a commercial-grade gutter sealant that retains adhesion and flexibility even in tough weather conditions, DAP polyurethane caulk is by far the best in its class. It was a little thicker than the other products we had tested, which made it a little difficult to exit the nozzle. That said, its performance more than made up for this initial shortcoming.

It is completely waterproof and even works for caulking gaps and cracks in areas permanently submerged in water. It can withstand a temperature range of -40⁰F to 170⁰F, which is much wider than the range of the two sealants we’ve reviewed so far.

It is super versatile and can be used in a wide range of applications, unlike silicone sealant products. Although we just tested it on the gutter, you can use it to seal gaps in your doors, windows, vents, ducts, expansion and control joints, gutter seam, and lots more. DAP polyurethane caulk is 100% weatherproof and exhibits remarkable elasticity even in extreme temperature fluctuations.

All in all, if you’re looking for industrial-grade gutter sealant for home or professional use, DAP will do the job.

  • Ideal for wet and dry applications, unlike silicone sealant or butyl rubber, caulks that don’t do well when exposed to moisture or surfaces with rust
  • Can withstand extreme temperature fluctuations without cracking
  • It has a smooth, paintable finish
  • 100% waterproof, including permanent submersion
  • Retains adhesion and elasticity in tough weather conditions
  • It takes 4-7 days to fully cure before you can paint your gutter system
Dap 7079818816 18816 Polyurethane Construction Adhesive and...
1,036 Reviews
Dap 7079818816 18816 Polyurethane Construction Adhesive and...
  • Adhesives & Sealants
  • Country of manufacture: United States
  • Manufacturer: Dap


DAP 3.0 Caulk – Best Premium Gutter Sealant

DAP Crystal Clear Premium Gutter and Flashing Sealant




  • Size: 9 oz.
  • Color: Clear
  • Compatible with: Plastic and metal
  • Weatherproof: Yes

We thought DAP polyurethane caulk was hard to beat until we tested DAP 3.0. To say we were blown away by its performance would be an understatement. For one thing, DAP specifically made this gutter sealant for outdoor applications only. It doesn’t crack, shrink, sag, or melt even in extreme heat or freezing cold weather.

The thing we liked most about it was how fast it worked. Once we applied it, it took about 30 minutes to dry up, at which point it became paintable. It delivers a smooth finish like nothing we’ve seen before. It blends seamlessly with any kind of building material substrate you apply it to.

We also noticed that it didn’t have that characteristic pungent odor synonymous with gutter caulk. We didn’t even need to wear a mask when applying it. It was that mild. This can be attributed to its significantly low VOC levels, rendering it virtually odorless.

It works great on both wet and dry surfaces and is backed by a lifetime guarantee. All in all, we were pleased with the results.

  • Can withstand a wide range of harsh weather conditions
  • It does not crack in extremely hot or icy cold weather, unlike other caulks like silicone sealant
  • 100% waterproof
  • Blends seamlessly with all kinds of material substrates
  • It is paintable in just 30 minutes
  • It is quite thick
DAP 18377 3.0 Crystal Clear Premium Gutter and Flashing Sealant,...
250 Reviews
DAP 18377 3.0 Crystal Clear Premium Gutter and Flashing Sealant,...
  • Sealant comes in a 9 oz. Cartridge, is intended for exterior...
  • Gutter and flashing point sealant can be applied to wet or dry...
  • Thanks to its Crystal Clear Color, the sealant will blend in...


How to Choose the Best Caulk for Gutters – Buying Guide


A man using caulk for roof repair

If you find yourself staring at your screen dumbfounded and overwhelmed by all the different gutter sealant choices that exist and are not quite sure which one to pick, this section is for you. Here are a few critical things to keep in mind when shopping for the best caulk for your cracked seamless gutter or siding.

Hybrid vs. Solvent-Based Caulk

It goes without saying that any product designated for use on metallic, plastic, or vinyl gutters needs to be waterproof. It should also be tough enough to withstand ice and debris synonymous with freezing weather. The buzzwords to keep an eye out for on the packaging include “tear-resistant,” “abrasion resistant,” and “flexible/elastic.”

Keep in mind that many of the sealants on the market do a pretty good job on metal gutters. These don’t always adhere to plastic.

Hybrid caulk (a combination of silicone, polyurethane, and butyl flex caulk) is generally designed for use on metal surfaces like aluminum. A solvent-based seam sealer works on both. Pay close attention to the packaging to check which surfaces particular solvents are compatible with.

Ease of Application

It is not unusual for caulk guns to break while trying to squeeze sealant through the nozzle of a tube. The solution would be to get a lighter caulk that’s not as thick or a better gun. If you’re caulking your gutter, we recommend the latter. Here’s why.

Polyurethane sealants are typically a lot tougher than most other caulk types. This makes them a good choice for gutters, roofs, and anywhere else that’s bound to take a beating. The downside is, their thicker consistency makes them difficult to work with – hence the “get a better gun” recommendation.

That said, their gooey texture that’s a little like old caulk or old sealant is a small price to pay for their durability.

Weather Resistance

Caulks designed for outdoor use should be able to withstand extreme weather conditions without cracking, tearing, sagging, or buckling. Look for products rated for -20⁰F to 120⁰F. This range means the caulk will expand and contract with the substrate material without giving out.

Also, look for products marked “corrosion-resistant” and “sun/ozone resistant.” You want to steer clear of silicone sealant.

Cure Time

Some caulk products dry up within 30 minutes. Others take as long as 4-7 days. While there’s nothing wrong with long curing times, it comes down to convenience.

Ensure the caulk you get has a smooth finish that blends seamlessly with the roof or gutter material. That way, when you paint over it, no one would be able to tell there was ever a crack in the first place. Check that the caulk you get is paintable beforehand.


What kind of caulk should I use for gutters?

It depends on what your gutter is made of. Most hybrid caulks work only on a metal roof or gutter surfaces. Solvent-based caulks work on both metal and plastic. That said, make sure the product you use is 100% waterproof and weatherproof.

Polyurethane caulk products deliver the best results for outdoor use. Loctite PL S30 and DAP Polyurethane Caulk are excellent options to consider. Whatever you do, don’t use acrylic latex.

What caulk do professionals use?

For indoor applications, acrylic latex caulk is the go-to gutter sealant for most professionals. It is easy to work with, can be applied using a putty knife, and can even be cleaned up with soap and water.

For outdoor applications, you’ll need an industrial-grade caulk that can withstand moisture and rust on metal gutters. DAP 3.0 Caulk is a solid choice for caulking a leaky gutter or roof. Silicone sealants don’t hold up quite as well.

What is the best caulk for outdoor use?

When looking for a roof and rain gutter sealant to use outdoors, ensure it is waterproof and can withstand extreme weather conditions without cracking or buckling. Polyurethane-based caulks like Sashco 14010 Caulk and tri polymer caulks are designed to take a beating. Unlike silicone sealants and acrylic latex caulk, these caulk products are specifically formulated for outdoor applications.


There you have it – the best caulk for gutters. Any of the products we’ve reviewed here are guaranteed to keep your leaking gutter or roof in check. If we had to pick one winner, though, it would, no doubt, be Loctite PL S30. Its performance is simply unmatched.