5 Common Types of Caulk: Which One Is Best for Your Next Project?

Caulk is a versatile sealant that you can apply to everything from sinks to gutters to chimneys, but for it to be effective, you’ll have to use the right type. So, how do you know which kind to choose? It’ll probably come down to one of these five common types of caulk: acrylic latex, silicone, siliconized latex, polyurethane, or butyl rubber. Let’s break down the differences between these varieties of caulk so that you can pick the right one for your project.

What Is Caulk?

Caulk is a flexible sealant used to fill gaps and seal joints around doors, windows, and plumbing fixtures. It also serves as an adhesive between different surfaces (like a sink and a countertop). 

There are several varieties of caulk, each with its own purpose. For example, some types are good for sealing showers to prevent water damage and mold growth, while others are better for filling cracks in masonry or concrete.

1. Acrylic Latex Caulk

Acrylic latex caulk—also known as latex caulk or painter’s caulk—is a multi-purpose type of caulk that you can use in a variety of projects. It’s a good choice if you need to seal baseboards or patch holes or cracks in your drywall, but it won’t hold up as well in kitchens, bathrooms, or other moist locations.

Best for: Filling gaps in wood trim or sealing baseboards

2. Silicone Caulk

Silicone caulk is highly flexible and elastic, so it won’t crack as easily as more rigid types of caulk (like latex caulk). For this reason, silicone caulk is ideal in areas that sit in direct sunlight or experience extreme temperature changes—like the exterior of your windows. It’s also recognized as the best caulk for showers because it holds up well against moisture and can prevent mold growth.

Best for: Creating a waterproof barrier around showers, tubs, sinks, and other plumbing fixtures

3. Siliconized Latex Caulk

Considered the best caulk for windows, this hybrid caulk offers the benefits of both latex and silicone caulk. This means it’s easy to work with and clean up (like latex), but it’s also fairly flexible and somewhat moisture-resistant (like silicone). 

With that said, siliconized latex caulk isn’t as effective as silicone at preventing water damage, so it’s better for areas that receive a modest amount of moisture—like a backsplash—rather than places that are constantly wet.

Best for: Sealing the interior and exterior of your windows

4. Polyurethane Caulk

Ideal for outdoor projects, this heavy-duty caulk adheres to many different surfaces and building materials, including wood, concrete, brick, and metal. It’s often used to seal gaps in windows and siding to prevent insects and rodents from entering a home.

However, polyurethane caulk is thicker and gooier than many other types of caulk, so it takes longer to dry and cure. In fact, while latex and silicone caulk dries in a few hours or less, it’ll take a full day for polyurethane caulk to dry.

Best for: Caulking between siding and windows to keep pests out

5. Butyl Rubber Caulk

Butyl rubber caulk—like polyurethane—is one of the best exterior caulks on the market today. Once applied, it creates a water-tight seal and holds up well against temperature changes, making it particularly effective for gutters and roofs. 

Butyl rubber caulk also works nicely on concrete and masonry, which is why it’s sometimes used on chimneys or foundations. For these types of projects, you should hire a handyperson or local caulking service rather than trying to apply the caulk yourself.

Best for: Sealing gutters, flashing, and other parts of your roof