Find the right formula to fill in your home’s gaps
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.
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.
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.
| Pros | Cons |
|---|---|
| Easy to apply | May crack or shrink over time |
| Cleans up with water | Not ideal in high-moisture areas |
| Can be painted | Can weaken in sunlight or high heat |
Best for: Filling gaps in wood trim or sealing baseboards
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.
| Pros | Cons |
|---|---|
| Excellent in wet and humid areas | Harder to clean up |
| Remains sturdy through temperature changes | Gives off a powerful odor |
| Can expand and withstand movement | Costlier than other types of caulk |
Best for: Creating a waterproof barrier around showers, tubs, sinks, and other plumbing fixtures
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.
| Pros | Cons |
|---|---|
| Simple application | Not as durable as pure silicone caulk |
| Stretchy and adhesive | Less water-resistant than silicone |
| Good for indoor and outdoor use | Has a strong smell |
Best for: Sealing the interior and exterior of your windows
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.
| Pros | Cons |
|---|---|
| Tough and durable | Difficult to apply |
| Can block pests from entering your home | Takes longer to dry and cure |
| Suitable for outdoor use | Challenging to clean up |
Best for: Caulking between siding and windows to keep pests out
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.
| Pros | Cons |
|---|---|
| Works on a variety of surfaces | Can be harsh and irritating to the body |
| Withstands movement and expansion | Not suitable for indoor use |
| Water-resistant | Messy application that requires a pro |
Best for: Sealing gutters, flashing, and other parts of your roof
Butyl rubber caulk may be better than silicone caulk in certain situations. For example, if you need to repair a leaky gutter or seal roof flashing, then butyl rubber caulk is the better choice. However, if you’re caulking an indoor shower or bathtub, then silicone caulk is a more appropriate option.
Yes, you should remove old caulk before adding new caulk. Start by cleaning the area, then use a sharp tool (like a utility knife or putty knife) to pull up the existing caulk. After you’ve pulled up one edge of the caulk, you may be able to peel the rest by hand—kind of like string cheese. If that doesn’t work, try softening the caulk by soaking it underneath a towel filled with hot water (for water-based caulk) or white vinegar or mineral spirits (for silicone-based caulk).
Yes, you should caulk a toilet to the floor for several reasons. Bathrooms are constantly wet—and if water splashes out of your shower and collects on your floor, you don’t want it seeping underneath your toilet, where it could potentially cause damage. Plus, caulk adds stability and helps prevent your toilet from wobbling.
