Best Sealant for Chimney Flashing

The Cleaning King Website Is Supported By Its’ Readers, This Page Contains Affiliate Links From Which We May Earn A Commission At No Extra Cost To Readers. Click Here For Full Disclosure.
7 Year Warranty

No products found.

Easiest to Use

No products found.

Our top Choice

No products found.

Best for small jobs and patches

No products found.

Best Tape Sealer

No products found.

How We Found the Best Sealant for Chimney Flashing

Customer Reviews

Product Testing

Team Experience

Chimney Flashing is meant to create a watertight seal where your chimney and roof intersect. But if the flashing was not installed properly, if it is subjected to a violent storm, or its sealant has deteriorated, it can start to pull away from your roofing material and lead to water leaks.

This article is a great read for those who are homeowners, professionals and anyone else who is having these issues.

This article is helpful for those who have leaks occurring in their chimney flashing and need quick information on how to fix the issue, what products to use, and where to get them.

Having a proper sealant for the chimney flashing is a great way to make sure the work is done correctly. Here at Cleaning King we strive to provide the best information for the most effective, affordable sealant for chimney flashing as well as all of your cleaning needs.

Our team took a look at all of the chimney flashing sealants available to help you pick the right one for your needs.

Buyers Guide – Best Chimney Flashing Sealant

Flashings are the strips of metal that are placed along the front edge, corners and ridges of your roof and around your chimney and skylights. They are meant to create a watertight seal where your chimney and roof intersect.

Chimney flashing can allow roof leaks in the transition area between the chimney and the roofing materials.

Porous bricks or faulty counter flashing can allow water to get behind the primary flashing and around the roofing materials, allowing water to come into your living spaces.

Unsealed chimney flashing is a very common contributor to chimney leaks and can end up causing major problems if it’s not taken care of right away. Your roof and attic can become damaged as a result of chimney flashing failure.

This is why you need to look for an effective sealant for chimney flashing to ensure that there are little to no leaks or issues moving forward. 

Many consumers prefer sealant that is going to match the colour of their roof or chimney. For example, many sealants come in brown, black and or darker colors.

Many consumers prefer liquid based versus tape sealant, although both are available on Amazon for purchase.

How to repair chimney flashing seals – Sealing around Chimney

Many homes begin with chimney flashing installed for foreseeable issues. At some point as a homeowner, you will have to repair the flashings that have been sealed prior. Here is how; Renew flashing seals by chipping out the old mortar and caulking along the edges of the flashing. Use special masonry caulk to seal the joints between the flashing and the chimney.

Seal the seam between the cap and step flashing with urethane roofing cement or silicone caulking compound. If you are working with valley flashing, lift the edges of the surrounding shingles, and spread roofing cement on the flashing about 6 inches in from the edge of the shingles.

If you are resealing drip edging, seal beneath the shingles, but don’t seal the drip edge along the eaves.

To replace flashing around the vent pipe, first remove the shingles covering the flange at the back and sides. Pry and lift off the flashing. Pull or cut off any nails. Position a new vent-pipe flashing over the vent, push it down into place, and nail where shingles will cover it. Replace the shingles, and cover the nail heads with roofing cement.

Our Reviews - Best Roof Flashing Sealant

Top Choice

No products found.

Best Roof Flashing Sealant – Our top choice

MasonryDefender Chimney Flashing Sealer is a flexible, waterproof coating that is applied to chimney flashings (where the chimney meets the roof ) to protect against water leaks. This permanently flexible membrane is easy to apply with a paint brush and will last for years. Available in black as of right now. 

This product not only seals chimney flashings, but can also be used around any other protrusions in roofs including skylights or vents. It provides a long lasting coating that is ready to use and can easily be applied with a paint brush. 

Covers 14 sq. ft. per half gallon (assuming 2 coats). Dries to touch in 30 – 60 minutes. Product cures completely within 6 – 12 hours depending on temperature/humidity. One caution about this item is it should not be used in cold, damp, rainy weather or the product may wash away. Allowing at least 12 hours of dry, clear weather for proper curing is most effective.

7 Year Warranty

No products found.

Best Sealant for Chimney Flashing – 7 Year Warranty

FlashSeal is a versatile and easy to use flashing repair system that, when dry, forms a flexible waterproof membrane. It’s formulated for permanent adhesion to asphalt shingles, metal flashings, brick, and other chimney and roofing materials.

Using FlashSeal to solve problem leaks around the base of chimneys, stacks, and vents. It is also great for sealing around skylights. Repairing flashings that have been tarred over, split, cracked, or are in disrepair is easy with FlashSeal.

It’s like installing a custom fit rubber boot at the base of the chimney!

It remains permanently flexible and has a 7 year warranty when used with FlashSeal Reinforcement Fabric. For complete chimney protection, the company recommends waterproofing the chimney and sealing the chimney crown. This product differs from others because it comes in more colors than the normal black color – brown in this case.

Easiest to Use

No products found.

Best Sealant for Chimney Flashing – Easiest to Use

This chimney flashing sealant stops leaks around the chimney flashings, skylights, stacks, & vents perfectly. The product remains permanently flexible to stop chimney leaks and is easy to brush-on application. The brush is not included within the product although is easiest when used with one.  

A great thing about this product is that it is ready to use upon purchasing. There is no mixing required before using. Clean up comes easily with soap & water. 1/2 Gallon is effective and covers 14 Sq. Ft. 

Every product that this company produces is produced under strict quality standards and formulated with the highest quality raw materials available. Our innovative solutions and coatings have stood the test of time, and are trusted by industry professionals and homeowners alike.

Stand-out features include

  • Includes night vision for crystal clear camera footage in the dark
  • Two-way audio to clearly speak to guests

Best for small jobs and patches

No products found.

Best Sealant for Chimney Flashing – Best for small jobs and patches

Loctite PL Roof and Flashing Polyurethane Sealant is a premium quality, commercial grade sealant developed especially for forming permanent, water and weatherproof seals in all exterior gaps and joints.

This sealant is elastic and remains flexible to expand and contract with construction material movement to protect and retain the original seal.

It provides properties of non-sag, permanent flexibility and corrosion resistance. It exhibits outstanding durability and tear resistance. It usually requires no primer and resists deterioration from weather, stress or movement.

It is UV and ozone resistant and does not soften in the sun. This product is made to be used on expansion joints; ± 25% movement, withstand harsh environments, has one-time application, blends with surroundings, complies to stringent Federal & State Regulatory Requirements, flexible, weatherproof, does not deteriorate, is paintable and made with low-VOC formula.

Best Tape Sealer

No products found.

Best Sealant for Chimney Flashing – Best Tape Sealer

This product differs from the others due to it being a tape product rather than a liquid product for the issue.

This product is a clear flexible seal repair tape that provides instant and watertight sealing to leaks on all surface types.

The product is a waterproof silicone-butyl adhesive enabling this clear shield patch tape to be applied on water-submerged surfaces.

The tough rubber backing on this waterproof tape can be used on wet surfaces, empowering the average person with little to no experience in repair to fix pipes, boats, chimney and roofing quickly with professional grade results!

This flexible rubber surface resists tears, heat and frost- making it a great outdoor stop leak tape even on extreme temperatures (-30F to 374F). This swift response patch seal tape can be applied to all weather types and on smooth or rough surfaces for long-term repairs as well.

Conclusion – Best Sealant for Chimney Flashing

 The Cleaning King team have elected as our top choice the MasonryDefender Chimney Flashing Sealer which creates a flexible, waterproof coating.  It is easy to apply, efficient, can last for years and can fix small problems before they turn into larger ones. 

No products found.

Best Sealant for Chimney Flashing FAQs

With proper installation, regular inspection, and consistent maintenance, chimney flashing can last up 30 years. But the longevity of flashing depends on many variables, including where you live, the type of material used, the size of your roof, and the type of roof shingles you have.

Some flashings are built into products like a bathroom vent roof cap or the standard plumbing vent pipe flashing. … It’s okay to use caulk and roofing cement as a last resort to make a temporary leak repair, but don’t allow a roofer to convince you they’ll work for the long term.

If you have a leak anywhere in your roof, including your chimney, homeowners insurance should cover any damage inside your house. Getting insurance to fix a leaky chimney, however, may be a long shot.

The following are some of the most common causes of chimney leaks. Chimney cap: The chimney cap protects the top of your flue from water entry, as well as animals and debris. … If flashing is incorrectly installed, damaged, or merely loses its seal due to wear and tear or age, water can easily seep through any gaps.

Renew flashing seals by chipping out the old mortar and caulking along the edges of the flashing. Use special masonry caulk to seal the joints between the flashing and the chimney. Seal the seam between the cap and step flashing with urethane roofing cement or silicone caulking compound, as shown at right.

$1000+ is an average starting price of chimney flashing. New flashing, if installed at the time your chimney is rebuilt is figured into the job total. If Chimney Rebuilding isn’t needed, and only flashing repair or replacement is requested, then it typically costs more.

Flex Seal will adhere to most any surface such as: wood, metal, tile, concrete, masonry, fabric, glass, plastic, aluminum, porcelain, dry wall, rubber, cement, some vinyls and so much more! Flex Seal may not be compatible with all plastics, vinyls, or rubbers.

As a result, chimney masonry should be protected from exposure to water. That’s why many chimney professionals recommend homeowners apply a waterproof sealer to protect the chimney from water damage. … So for optimum performance, waterproofing should be reapplied every five years.


Filling the cracks with concrete Caulking – the cracks Sealing the chimney crown to prevent further cracks can cost between $500-$1000.

Yes, Flexible Seal will adhere to brick, metal flashing and most roofing materials while providing a water tight seal. My roof is leaking around the flashing on the chimney where a black roofing repair product was used and it has cracked.