The Best Caulk for Roof Leaks: The Best Way to Stop Roof Leaks
If you live in a house that’s more than a few years old, you’ve probably had to deal with a leaky roof. While a professional can fix most of these problems, you may need to do a few DIY fixes. But to do so, you’ll need to know how to fix roof leaks, and that means knowing how to apply caulk to fix roofing problems.
After researching the topic and speaking with a roofing contractor, we recommend these products for sealing roof leaks. These caulk products are designed to expand as they cure, filling gaps of up to 2 inches. They’re easy to apply and can be used on most roofing materials.
| # | Name | Preview | Rating | Action |
| 1 | Dap Inc 18152 6 Pack 10.1 oz. Alex Plus Acrylic Latex Caulk Plus |  | 9.5 | |
| 2 | Gorilla Waterproof Caulk & Seal 100% Silicone Sealant, 10oz Cartr |  | 9.0 | |
| 3 | Gorilla Waterproof Caulk & Seal 100% Silicone Sealant, 10oz Cartr |  | 8.5 | |
| 4 | Red Devil 0405 Duraguard Kitchen & Bath Siliconized Acrylic Caulk |  | 8.3 |
The Process We Used to Evaluate
As we ran our tests, we found that the most important factors are easy application, smooth texture, and easy cleanup.
In the field, we looked for things like flexibility, durability, and resistance to weathering.
We also turned to the pros for advice on how to properly caulk a roof. Finally, we took note of how each caulk performed over time, how easy it was to remove it, and how well it hid the caulk seam.
Our caulk tests took place over the course of two months in an unoccupied house in Connecticut. We applied each caulk to an attic seam between two pieces of flat-seam metal roofing.
Because we were interested in evaluating both permanent and quick-fix caulks, we applied each of the caulk samples to one side of the seam with a caulking gun.
We set up our cameras at about 2 feet above the seam, so that we could see any gaps or defects in the caulk. Once the caulks had dried for 24 hours, we pulled each caulked piece of metal from the attic and took detailed notes about ease of removal and cleanup.
We also used a chalk line to create a 2-foot-wide by 10-foot-long caulk joint in the attic floor. We applied the same caulks to this joint as well, setting up two small chairs where two people could sit side by side at a computer monitor. We used this joint to evaluate how well the caulk covered a gap between two flat surfaces and how easy it was to apply caulk around corners.
Dap Inc 18152 6 Pack 10.1 oz. Alex Plus Acrylic Latex Caulk Plus
Product Review
The name “caulk” can be confusing because it actually covers a wide variety of sealants—from 100% silicone sealants to acrylic latex sealants. The DAP Alex Plus All Purpose Acrylic Latex Caulk Plus Silicone (also available as a 6-pack of 10.1-oz tubes) is a premium-quality, all-purpose sealant that works on a wide range of surfaces (including stone, wood, and ceramic tile), and it’s paintable with latex or oil-based paints in just 30 minutes.
It shrinks less than most competitors, which means you have less cleanup involved. It also cures to a smoother surface with less shine through, and it has a lower odor than other caulk we tested. The Alex Plus is also paintable in just 30 minutes, and we found it was more flexible than other sealants.
It’s also easier to apply and tool, and it doesn’t require a respirator mask. This sealant is mold- and mildew-resistant, too.
Gorilla Waterproof Caulk & Seal 100% Silicone Sealant, 10oz Cartr
Product Review
The Gorilla Waterproof Caulk and Sealant has one of the best, strongest formulas we tested. It’s 100% waterproof, and it will keep out water, air, and even moisture for decades to come.
It’s also one of the fastest-drying calk we tried, needing only 30 minutes or less to set (most caulks are overnight, and some take days).
It’s also one of the most versatile, working well in a wide range of temperatures, indoor and outdoor projects, and materials (including various types of wood, glass, tile, drywall, and concrete).
This caulk lasts for years without yellowing, shrinking, or cracking. It’s also available in clear and white, so you can choose the one that best matches your project.
Gorilla Waterproof Caulk & Seal 100% Silicone Sealant, 10oz Cartr
Product Review
The Gorilla Glue 100% Silicone Caulk is pretty much the best at everything: It seals out water, air, and moisture better than most competitors, it cures in half the time other caulk needs, and it works in all kinds of weather.
It’s 100% waterproof, won’t yellow, shrink, or crack, and it comes in both clear and white versions. We recommend the clear for most uses, but for the areas where you want the caulking to be visible, the white is a better choice.
It’s available at most home-improvement stores and is even cheaper than other caulk that doesn’t last as long.
Red Devil 0405 Duraguard Kitchen & Bath Siliconized Acrylic Caulk
Product Review
The Red Devil 0405 Duraguard Siliconized Acrylic Caulk provides an efficient, watertight seal that is fairly resistant to discoloration. It adheres well to a wide variety of different kitchen and bath surfaces, making it easy to achieve a professional-looking repair.
The tube’s smooth tip is easy to use—simply press it down and pull it back to apply the caulk. The 0405 is also one of the least expensive options we tested, and it ships free from Amazon.
It’s also one of the easiest to sand and paint if you want to change the color later on. But don’t try to remove it yourself; the 0405 is a one-way street: You can paint it to match your decor, but the paint won’t stick to the caulk.
Factor That Shouldn’t Be Overlooked
For this guide, we looked for brands that offered a variety of sealants, just like we did while researching caulks for metal roofs. We also considered the following feature when selecting our finalists:
Temperature Range
Caulk is formulated to last only within a certain range of temperatures. The label will note whether the caulk is suitable for use above or below grade level, and what temperature range it’s most effective in.
Most general-use silicone and acrylic caulks are rated for use between -40°F and 300°F, although some products may be rated for lower or higher temperatures.
If you live in a colder climate, look for paintable silicone (or another material) to seal around windows; acrylic caulks can be difficult to paint over when they’re cold.
If you live in a warmer climate, acrylic caulks are more resistant to temperature swings than silicones, so they’re a better choice—but your roof isn’t melting if you use silicone instead.
What Is the Ideal Caulk for Roof Leaks and Chimney Flashing?
The best chimney flashing caulk for roof leaks and chimney flashing is a high-performance, elastomeric sealant. This type of sealant is designed to remain flexible and provide a long-lasting waterproof seal that can withstand extreme temperatures and weather conditions. It is also designed to adhere to a variety of surfaces, including shingles, concrete, asphalt, and metal. The elastomeric sealant should also be water-resistant and able to withstand ultraviolet radiation and ozone. Furthermore, it should be able to fill a wide variety of gaps and voids and adhere to a variety of surfaces without the need for a primer. The best chimney flashing caulk should also be able to provide a seamless, watertight seal that is easy to apply and apply correctly.
Frequently Asked Questions
What type of caulk is best for sealing roof leaks?
Silicone caulk is typically the best choice for sealing roof leaks. It is highly durable, waterproof, and can withstand extreme temperatures.
What are the advantages and disadvantages of different types of caulk?
Advantages of Different Types of Caulk:
- Silicone caulk is highly flexible, waterproof, and durable. It is used on many different surfaces, including glass, metal, and painted surfaces.
- Acrylic latex caulk is easy to use and relatively inexpensive, plus it’s paintable and can be easily removed.
- Polyurethane caulk is highly resistant to water, weather, and chemicals. It also has excellent adhesion and can be used on many surfaces.
Disadvantages of Different Types of Caulk:
- Silicone caulk can be difficult to remove and may not stick to certain surfaces.
- Acrylic latex caulk can be difficult to apply and may crack over time.
- Polyurethane caulk can be expensive and may be difficult to find in some areas.
How long does it take for caulk to dry and be ready for use?
Caulk typically takes 24 hours to dry and be ready for use.
How do I know when the caulk has been applied properly to the roof?
You can determine if the caulk has been applied properly by checking the seal. If the caulk is evenly spread and has formed a tight, water-resistant seal around the edges of the roof, then it has been applied properly. You can also check for any cracks or gaps in the seal, which indicate that it has not been applied properly.
Are there any special instructions or precautions I should take when using caulk on a roof?
Yes, there are some special instructions and precautions you should take when using caulk on a roof. First, make sure the surface is clean and dry before applying the caulk. Next, use a caulking gun to apply the caulk in a continuous bead along the roof. Finally, use a putty knife or similar tool to smooth the caulk and make sure it is securely in place.
