Chimney Tuckpointing: Do’s and Don’ts for Selecting Mortar

Sashco Flexx
December 1, 2021 at 6:00 a.m.

By Cass Jacoby. 

Choosing the right caulk for tuckpointing will deliver unmatched results on your home. 

While the bricks in a chimney can last for decades, mortar has a shorter lifespan. The mortar can deteriorate over time due to harsh conditions or weather, but the bricks themselves can still be in good shape. Thus, tuckpointing comes into play.  

The most cost-effective option for homeowners is to have the affected areas of their chimney repaired rather than replaced. Specially formulated caulks, like Sascho’s Mor-Flexx caulk, ensure good adhesion on brick and other masonry services significantly extending the lifespan of a chimney. Additionally, caulking can provide an airtight, watertight seal between two materials, and can make a chimney more efficient.   

If you want beautiful fixes on your chimneys, then get to know what makes a good caulk. This guide will shed light on the do’s and don’ts for selecting the best caulk. 

Do: Select a weatherproof product 

It might seem obvious, weatherproofing a chimney is crucial. It is the best way to prevent chimney leaks and will protect and preserve the chimney for much longer. A waterproof and high-durability caulk, like Mor-Flexx, is the key to creating a tight, long-lasting seal that permanently weatherproofs the chimney.   

Don’t: Choose a silicone caulk

Silicone caulk is a quick fix, but will likely crack and hardly last more than six months. Silicone caulks are not made to handle movement without pulling away or cracking. Using this type of caulk will likely require callbacks because it is not customized for brick-and-mortar adhesion. You will be much better off using a flexible caulk that maintains its elasticity over time.  

Do: Choose a mortar-compatible product 

Mor-Flexx has a textured matte finish which is a better match with a realistic mortar finish for all EIFS, mortar, stucco, concrete, stone installations and repair needs. Mor-Flexx blends well with the chimney and is compatible with latex paint and most oil-based paints, sealers and stains. It won’t cause paint gloss, making it easy to use on any color for a discreet repair. Mor-Flexx may look like mortar and stucco but it stretches like rubber, staying elastic year after year to provide strong, stable support.  

Don’t: Choose a messy product 

Mortar mixing for a tuckpointing job can be time-consuming and messy, so your contractor will likely choose a caulk that is simple to use and carry onto the roof. Instead of your roofer having to carry the concrete powder, mix bucket and big trowel up to the roof, Mor-Flexx is a portable and clean product. Mor-Flexx has a water-based formula for easy application and water clean-up without being a stinky, stringy mess.  

Do: Prioritize longevity

When tuckpointing, the main goal is to avoid a complete repointing job down the road, so make sure the product used is a proven, durable solution. You want a caulk that is able to move with a future settling to provide long-lasting results. Mor-Flexx is an elastomeric with powerful adhesion, it won’t tear, crack or pull away, but will stretch. Mor-Flexx can stretch up to three inches wide with no slumping, staying where it is applied for a permanent, tight seal. 

Don’t: Select a product that stands out 

Your contractor wants to maintain the aesthetics of the chimney by blending the caulk in perfectly with the existing mortar to create a seamless design. The textured formula of Mor-Flexx is so easy to apply, smooth out and clean up that even a novice can execute a seamlessly blended, beautiful repair on crumbly mortar. Plus, Mor-Flexx comes in multiple colors and is paintable to ensure a tuckpointing job that basically looks invisible and maintains the beauty of the chimney. 


Ultimately, caulking is a solution in addition to typical mortar. When faced with selecting a caulk for a tuckpointing job, it is best to go with a simple solution that looks good and lasts. Choose a product with a weatherproof seal, that blends to easily disguise repairs and stays elastic over time. If you are looking for a product that will preserve the durability and beauty of your chimney, look no further than Mor-Flexx for a beautiful finish. 

Have a question? AskARoofer.

Find your local roofing contractor in the RoofersCoffeeShop® Contractor Directory.

About Cass  

Cass works as a reporter/writer for RoofersCoffeeShop and AskARoofer. When she isn’t writing about roofs, she is writing about movies for her master's degree and dancing with her plants.

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