best roof sealant for leaks

What is the Best Roof Sealant for Leaks?

Roofs are exposed to a daily assault from sun, wind, hail, rain and snow. Over time, this can cause minor leaks which can lead to costly damage over time. By applying the right sealer, you can patch potential problems and prolong your roof’s lifespan. Read on to learn which roof sealants are best for patching leaks.


Before you get started, you need to consider the scope of the problem. Do you have a tiny leak or more extensive, widespread penetration? While some sealants are capable of plugging small, isolated leaks, others can help create a larger barrier against sun and water over your entire roof. If you choose the wrong type of sealant, you will end up with a recurrence. Unfortunately, you may not even know it, especially if the leak is small and slow.

Over time, such a leak could lead to thousands of dollars in mold damage. For this reason, it’s best to leave roof repair to the experts, who have the experience and expertise to thoroughly repair or restore a roof so it’s 100-percent reliable. If you’re dead-set on patching your roof yourself, however, here’s what you should know.

What Sealants Can Do

Roof sealants are formulated to serve two critical purposes: to repair your roof and protect it in the long term. Depending on the product, roofing sealants can generate a seal against moisture and ultra-violet rays. They can also repair minor leaks before they lead to expensive rot and mold damage.

While certain sealants work fine on a variety of roofing materials; most are designed to work with specific roofing materials. Roofing materials such as metal, rubber, asphalt shingles and composite shingles all have varying characteristics that require special considerations. Roof pitch can also influence the kind of sealant you should choose. Certain sealants are only designed for minor, “touch-up” style repairs, while others can be slathered on to cover larger leaks.

Finally, some damage is simply too extensive for a roof sealant. Old, decaying roofs will also typically respond poorly to sealants. In both of these instances, it’s generally better to replace the entire roof to avoid the risk of future leaks down the line.

roof sealant for leaks

Larger Leaks

If you have noticed leaking in more than one spot, you will need to repair any damage and apply sealer to the entire roof.

Roofing sealers can be divided into two fundamental categories: solvent-based and water-based. While solvent-based sealers hold up quite well against harsh weather, they also tend to be more expensive and difficult to apply due to their thickness.

On the other hand, water-based sealants are cheaper and less toxic. On the downside, they don’t hold up as well to harsh weather conditions. They also tend to degrade quicker than solvent-based roofing sealants, meaning you will need to reapply more frequently.

Because solvent-based sealers emit toxic fumes, they require the use of a reliable, professional-grade respirator. No mask is required for the majority of water-based roofing sealants. They also tend to go on easier due to their thinner consistency. That said, this makes them difficult if not impossible to use on steep roofs.

It can be hard to dispose of most solvent-based roofing sealants. In most instances, you will have to take unused portions and containers to a dedicated local facility for harmful chemicals. On the other hand, empty water-based sealant containers can be added to your regular trash.

Before choosing a product, read the label to make sure it is specifically formulated for your roofing material.

Minor Leaks

If you have one or two minor leaks, you may be able to get by with a liquid rubber sealer. Available at local hardware and home improvement stores, these products usually come in tubes, which fit within caulking guns. Liquid rubber patches are also available in spray cans.

Roof sealers also come in acrylic, which is moderately moisture resistant, and polyurethane, which isn’t very resistant to UV rays. Silicone products are also available, but these tend to be a bit pricier. You can also try using sealant tape or patches, which have adhesive backing that sticks to leaks or especially vulnerable seams.

Unfortunately, there’s no sure-fire way to predict whether any of these products will do the job. Even if they are able to stop a leak, there’s a good chance the patch will fail over time. For this reason, it’s almost always better to work with a reputable local roofer with years of experience sealing and patching roofs of every kind.

Need a new roof for your home? A to Z is ready to help. Hoping for cost-friendly repairs for weather-related damage? We can do that too. At A to Z, we’ve developed a widespread, well-earned reputation as one of the state’s premier roofing contractors by providing expert workmanship and attentive, honest customer service. Contact us to learn more.

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