Guide to Gutter Patches and Sealants

Leaky gutter

Gutters can spring leaks. It’s just the way it is. You can replace the leaky section, or in many cases, you can save time and money by patching or sealing the leak, provided you know what types of gutter patches and sealants to use.

It’s important to know that not all sealants are the same. There are different varieties to fix different problems. Perhaps the leak is caused by a hole, or maybe it’s the result of a bad joint or seam.

Why Gutters Leak

Your gutter system collects and diverts rainwater, preventing leaks. However, if your gutters are already leaking, your house and your wallet will be in for a world of hurt.

For the purposes of this article, we’re talking about leaks in the structure of the gutter itself. We’re not addressing how water overflows from clogs or spills out because the gutter is bent or sagging. But if that’s the problem, here’s an excellent article on fixing sagging gutters.

Meanwhile, here are some of the reasons gutters leak.

  • Holes and Gaps: Even the sturdiest gutters can develop small holes and cracks over time, and they can grow if not fixed. Fortunately, you can fix most small holes by applying waterproof sealant over them.
  • Expansion and Contraction: Gutters expand in the heat and contract in the cold. This puts pressure on the seams where gutter sections join and can cause them to separate enough to leak. 
  • Age: Constant exposure to the elements causes gutters to deteriorate and leak, particularly in older gutter systems with aging sealants.

The Consequences of Leaking Gutters

When gutters leak, they become ineffective, leading to:

  • Damage to your home’s foundation.
  • Rotted fascia boards
  • Rotted siding
  • Pooling water near and around the foundation of your house.
  • The gutters becoming worn enough to fall off
  • Cracked and water-damaged driveways
  • Stains on your concrete and siding
  • Soil erosion

Repairing fallen gutters and structural damage is expensive, so if you see leaking gutters, fix them as soon as possible. 

Caulk vs. Sealant

There are two basic products for closing wounds on gutters – caulk and sealant. Both terms are used interchangeably, both are used to fill cracks and gaps, and both can be applied with a caulking gun. The difference is elasticity.

Caulk is made of latex and acrylic materials, which makes it more rigid than sealants, which are made of silicone. Because of this, it’s prone to cracking, especially under high-temperature fluctuations, and thus you shouldn’t use it to seal gutters.

Types of Gutter Sealants

Builder applying seal to guttering
Photo Credit: Mypurgatoryyears / Canva Pro / License

The best rain gutter sealants are either water- or solvent-based. 

  • Water-based sealants are thinner in consistency and easier to apply but need to be applied more frequently and degrade in half the time.
  • Solvent-based sealants are thicker, adhere more quickly, and last longer. But they produce strong odors and can irritate skin and eyes, so wear gloves and safety goggles while using them.

There are multiple types of sealants, each with considerable differences:

Liquid Rubber Sealants

Versatile and water-based, liquid rubber sealants offer all the benefits of their solvent-based counterparts without the toxicity. You apply them with a brush or roller.

These sealants create watertight seals, which prevent moisture from escaping. They’re paintable and work both indoors and outdoors. They’re also UV-stable, meaning the sun’s rays don’t damage them.

However, they can take up to 48 hours to dry after being applied, and when they do dry, they turn black or brown, making them less pleasing to look at. Additionally, you may need to apply more than one coat. 

Where to Buy: Liquid Rubber Waterproof Sealant

✓ Paintable
✓ Non-toxic
✓ Flexible
✓ Resilient against the sun’s rays
✗ Slow to dry
✗ May need more than one coat
✗ Not aesthetically pleasing to look at after drying

Butyl Rubber Sealants

Butyl rubber sealants are effective in temperatures from 20 to 120°F and on both wet and dry surfaces. They adhere quickly and remain flexible after drying. This allows them to flex with the gutter as it expands and contracts, all while ensuring a watertight seal.

However, they take a little skill to apply, as they’re dispensed from a caulking gun. Additionally, if left uncovered, they dry out quickly as they don’t have a cap. Furthermore, while they can withstand high temperatures, they lack UV protection.

Where to Buy: DAP 18377 3.0 Crystal Clear Premium Gutter and Flashing Sealant

✓ Handle cold and hot temperatures
✓ Work on wet and dry surfaces
✓ Remain flexible after drying
✓ Don’t shrink or crack as the gutter moves.
✗ Hard to squeeze out of the tube
✗ Dry out quickly
✗ No UV protection

(Poly)urethane-Based Sealants

Urethane-based sealants are designed specifically for sealing around galvanized, vinyl, and aluminum gutters. They have strong chemical and weather resistance and plug up cracks and holes of all sizes. Additionally, they can be easily painted and resist mildew.

Urethane-based sealants take anywhere from one to two days to fully dry. Apply them carefully, as they need correct installation and curing to last a long time.

Where to Buy: OSI GS121 Gutter and Seam Sealant

✓ Resist mildew
✓ Flexible
✓ Strong chemical and weather resistance
✓ Easy to paint
✗ Needs to be installed carefully
✗ Takes 1-2 days to dry

Seal Tape

Unlike the other products, this one is a tape, making it easy to apply: just tape over the leak. It’s designed for multiple surfaces, including wood, glass, and acrylic. Regardless of the surface, it seals large holes and cracks on pool liners, roofs, gutters, and vehicles.

Seal tape is versatile; you can use it indoors, outdoors, and even underwater. It also has strong UV and weather resistance, as it resists sunlight and temperatures ranging from -70 to 200°F.

Even though you can apply it wet, it works best on dry surfaces because adhesion to wet surfaces is always a little iffy. You should also apply it on smooth surfaces rather than rough surfaces. Finally, it’s very sticky, so it can be tough to cut with scissors.

Where to Buy: Gorilla Waterproof Patch & Seal Tape

✓ Versatile
✓ Repairs instantly
✓ Withstands sunlight, freezing, and high temperatures
✓ Works on many surfaces
✓ Can be applied underwater
✓ Flexible
✗ Can fail when applied to wet surfaces
✗ Hard to cut with scissors due to stickiness
✗ Doesn’t work on rough surfaces

How to Pick the Right Patch or Sealant

Choosing the right gutter sealant is challenging. No sealant is better than the other. The gutter material is the main factor, but other factors are involved, such as the location and type of leak, prevailing weather conditions, drying time, and flexibility of the final seal.

Here are what all the sealants have in common:

Adhesion strength and surface

How well a sealer adheres to the gutter material is crucial. No single sealant is best for all surfaces, and some don’t stick to certain surfaces at all. Check your gutter sealant’s compatibility before applying it. 

The most common types of gutter materials are vinyl and aluminum, but galvanized steel, zinc, and copper are also used.

Note that general-purpose sealants are a jack-of-all-trades, master of none. They are very versatile but generally aren’t the best sealant for the job compared to more specialized options.

Dry time, flexibility, and durability

When choosing a sealant, you should be cognizant of its drying time, its flexibility properties, and its durability.

Drying Time: Gutter sealants require anywhere from under an hour to two days to dry and cure. That makes a big difference if you want to paint over them as soon as possible. If you have to complete the job quickly, then, you may opt for a quick-drying product.

Flexibility: A sealant’s flexibility is crucial to its success. Gutters frequently shift due to wind, and temperature changes can cause them to expand and contract, compromising the integrity of the repair. If you live in a region prone to extreme temperature fluctuations, choose a formula that will flex with the gutter or gutter seam. This particularly applies to metal gutters, which expand and contract under fluctuating weather.

Durability: Durability also extends to protection from the elements. For example, UV-resistant sealants are protected from the sun’s rays. Sealants with chemical resistance are also worth looking into. For instance, if you live in a coastal area, look for a sealant with resistance to salt.


Sometimes, you just need to do a simple gutter repair. If that’s the case, it might be more economical to buy a more versatile sealant. Some sealants can be used for a variety of coating and repair purposes, such as sealing around window frames and fixing holes in pool liners. 

If you need such a sealant, check its shelf life before buying it. Some sealants have a shorter lifespan once opened, and it’s frustrating to use them to repair your gutters only for them to harden and become useless six months later if you need them for another task.

Frequently Asked Questions

How long does a gutter sealant last?

It depends on the type of gutter, weather conditions, and the type of sealant used. Some brands offer a lifetime guarantee, while others last anywhere from one to four years.

How long after rain can I put sealant on the gutter?

Some polyurethane sealants can be applied to wet gutters. However, it’s generally recommended to wait until your gutters are completely dry before applying sealant. If waiting isn’t an option, apply the sealant two to three hours after the rain stops. 

How can I remove old gutter sealant?

Use a sealant remover, mineral spirits, or lacquer thinner. Apply a small amout, allow it to sit, and remove it with a putty knife or chisel. Repeat the process if necessary, and wipe away any remaining residue until you get a smooth, clean surface.

When to Hire a Pro

If you don’t know what sealants or patches to buy, MyGutterGnome can put you in touch with gutter experts who will give you all the information you need.

*MyGutterGnome participates in the Amazon Services LLC Associates Program, an affiliate advertising program. MyGutterGnome may earn revenue from products promoted in this article.

Main Photo Credit: LeslieLauren / Canva Pro / License

Stuart Kushner

Stuart Kushner is a writer and aspiring product designer based in New York City. When he isn’t doing either, Stuart enjoys heavy metal music, exercise, and trying new food and drinks.