Whether you’re a painter, a homeowner, or a construction worker, the odds are that you’ll need exterior caulk at some point. Outdoor caulk is essential for preventing moisture, insects, and other nasties from invading or damaging your home.
It’s also important to maintain the internal temperature of your home and increase its efficiency. In this article, we will look at a list of the best exterior caulk and how to choose the right one for your project.
Our Top Picks
Best General Purpose Caulk For Outdoors
Gorilla Waterproof Caulk & Seal
Best Caulking For Exterior Windows
Red Devil Window & Door
The Best Caulking For Outdoors
Gorilla Waterproof Caulk & Seal
Gorilla Waterproof Caulk & Seal is the perfect general-purpose caulking for outdoor exterior projects.
Gorilla caulk is water resistant in 30 minutes, it won’t shrink, crack, or yellow, and you can use it indoors as well if you wish.
It’s the perfect caulking to prep your exterior before painting or to weatherproof your home by filling all the gaps and cracks.
Choosing the Best Exterior Caulking For Outdoors
Choosing the best exterior caulk is difficult but essential. There are so many different kinds of caulk, which can make the choice confusing. There are also tons of factors to consider that could impact how well your caulk seals and adheres to a particular surface. Choosing the wrong caulk will result in an imperfect seal and could potentially allow pests and pathogens to cause damage to the interior of your home.
The best exterior caulk will save you money on your heating and cooling bills. Caulk is a two-way street in that it keeps the thermostat-set temperature inside your home, all while keeping other things outside of it.
Where Should I Never Use Exterior Caulk?
A common misconception that many people have regarding caulk and sealant is that it’s a cure-all. However, there are certain places where you should never use even the best exterior caulk because it will cause more harm than good. Let’s look at a few of those places.
Window Weep Holes
Window weep holes are designed to give rainwater and runoff a place to go after it falls. If you caulk your weep holes, there’s a good chance your window sill and trim will end up rotting and becoming moldy because the rainwater sat stagnant instead of flowing away.
Garage Door Panels
You must never caulk between your garage door panels. Caulk will stick the panels together and prevent them from opening and closing properly.
Caulking underneath siding will cause the same problem as caulking weep holes in windows. Water will get trapped behind the siding and potentially cause water damage and mold to the walls of your home.
In Doors and Windows
Caulking around doors and windows is beneficial as long as the caulk doesn’t end up on the wrong part of the window or door. Be careful where you apply caulk to that it doesn’t cause doors or windows to stick closed.
Caulk and sealant are great tools for homeowners and construction workers, but only when they’re used in safely in the right places.
What Are the Most Common Kinds of Exterior Sealants?
Now that we know the importance of sealants and where you should use them, let’s look at the most common types of sealants. We’ll also look at the proper application for each sealant for best results.
Exterior Latex “Painter’s” Caulk
If you’re a painter or a painting contractor, you’re likely familiar with one of the best exterior caulks, which is latex caulk, or specifically water-based latex. Latex caulk, also known as latex painter’s caulk, is one of the easiest caulks to manage and clean up after. Painters prefer it because it’s easy to paint over, and not all sealants do well with paint.
Latex caulk is very durable and lasts anywhere between 4 to 8 years, depending on the quality. Whether you’re sealing around window trim, expansion joints, or anywhere else, latex caulk is an excellent choice. The only downside is that it doesn’t stick well when you apply it in conditions that are moist or less than 40 degrees Fahrenheit.
Exterior Butyl Rubber Caulk
Butyl rubber caulk is very flexible and sticks well to masonry, metal, gutters, and other tricky surfaces. Its flexibility also makes it the perfect caulk to apply to a surface that will move and shift about. Chimney flashing, roofs, and other outdoor areas are the perfect place for butyl rubber caulk. Be warned, however, that butyl rubber caulking shrinks with time, so don’t use it to fill large gaps.
Exterior Acrylic Latex Caulk
Acrylic latex caulk is very similar to latex caulk. It can do all the same things and has the same benefits that latex caulk has, but it’s longer-lasting. This type is on our list of the best exterior caulks because you can expect to get anywhere between 10 and 25 years of life out of acrylic latex caulk.
Exterior Polyurethane Caulk
Exterior polyurethane or urethane caulk is one of the top exterior caulks on the market. It’s UV resistant, which means that it won’t yellow or discolor if it’s been in the sun for too long. Polyurethane caulk is a one of the best exterior caulks for roofers and those who apply a sealant to sunny areas of buildings. It can also be painted over and has a slight flexibility to it.
It can also be applied to most surfaces and is perfect for areas when two different surfaces meet each other. The only downside of polyurethane and urethane caulking is that it’s expensive and extremely messy to work with.
Exterior Silicone Caulk
Look no further than silicone caulk if you’re looking for the godfather of exterior caulking. Contractors, homeowners, and everyone outside of painters love silicone caulk and sealant. It’s on our list of the best exterior caulks because it’s one of the most durable and water-resistant options on the market, and it’s also extremely flexible and easy to work with, but not as easy as latex.
The only thing you should be warned about with silicone caulk is that you usually can’t paint over it, and it’s extremely difficult to remove once it hardens. However, it’s very affordable and versatile, making it a great all-around product.
Hybrid Exterior Caulk
Hybrid caulk is like the best of both worlds when it comes to caulks and sealants. It combines the adhesion and flexibility of silicone to the longevity of polyurethane caulk. Hybrid caulks are also easier to apply neatly than polyurethane but not quite as easy as acrylic latex. The downside of hybrid caulks is that they’re usually quite expensive because they’re one of the best options for all types of projects.
What to Consider When Choosing the Best Exterior Caulk
Now that we know the different caulking options available to us, let’s look at things to keep in mind when making your selection. These factors will affect which sealant you choose and how well it will perform.
Durability is an extremely important thing to consider when choosing your caulk. If you’re trying to seal an area that will see lots of rain, snow, cold, and seasonal changes, you need something that can adapt to the changes. Polyurethane, silicone, and rubber butyl are the most durable and multi-functional sealants and would be the best exterior caulks to consider for this job. Latex and acrylic latex are the least durable.
How easy it is to use the product is also important, especially if you’re not an experienced caulker. Sealants such as rubber butyl, polyurethane, and silicone are more durable, but they’re also tougher to use. Any type of latex caulk is easier to apply, clean up, and work with than other types of caulk.
The area where you’re applying the sealant also makes a difference in which type would be the best exterior caulk for you. If the caulk needs to be neat, tidy, and aesthetically pleasing, then latex and acrylic latex are your best bet. Silicone and polyurethane products are usually thicker and gooier, making them more difficult to apply neatly.
Not every type of caulk can stand up to extreme temperatures, whether they be hot or cold. Some may have difficulty setting up initially in extreme heat, while others may not be suitable for homes in very cold or windy environments. Humidity, rain, snow, and sun exposure also play a role in which would be the best exterior caulk for you.
Just as you do with paints and stains, you should always check the label of your caulk to see which surfaces they can adhere to. “Latex concrete,” silicone, polyurethane, and butyl rubber caulk are the best exterior caulk choices for mortar, brick, and rock surfaces. Wood, however, might require more delicate caulking, such as latex or acrylic latex.
Color isn’t a big deal if you’re using latex or acrylic latex caulk because you can paint over it. Polyurethane and rubber butyl can also be painted over. Silicone, however, doesn’t adhere well to paint, so the color is something to keep in mind when making your sealant selection. Luckily, because of how difficult sealant is to paint, many colors are available to choose from.
Curing time for caulking refers to the amount of time it takes to dry completely from the inside to the outside. Curing time depends on the product you choose and the conditions you apply it in. Typically, all types of exterior caulk will dry within half an hour, but the curing time is closer to several days.
Wrapping Up the Best Exterior Caulk
As you can see, there are a ton of things to keep in mind when choosing the best exterior caulking for outdoors or sealant for your project. It’s important to keep each of the previously mentioned factors in mind and never apply caulking in an area that isn’t designed for it. Caulk is a great all-around tool, but it’s not a cure-all for every situation.
If you’re going to caulk an exterior area that will be seen close up, like around a ground-level window, it might be worth it to use acrylic latex or latex since these are easier for the paint to bond to. If durability is your priority and it’s an area that won’t be seen frequently, then polyurethane or silicone will be a better choice, even though they are messier to apply because they will last longer and don’t need to look pretty.
You should also make sure to perform a practice run with your caulk and caulk gun before permanently applying it to a surface. With a little practice and prep work, you’ll soon have your house sealed up tighter than Fort Knox.
Check out our Exterior Painting page for even more information on exterior painting, paints, and products.
I’ve been a professional painter since 2001 and spent the last 12 years specializing in kitchen cabinet refinishing. I started the DIY Painting Tips blog in 2015 to start sharing everything I’ve learned over the years and help all the people who’d rather tackle their painting projects themselves. In 2019 I started the DIY Painting Tips Youtube channel where I publish in depth videos all about kitchen cabinet painting, painting gear reviews, and interior/exterior tutorials.