The Importance Of Waterproofing Chimney Maintenance

Keeping water from intruding into your chimney and into your home is an important consideration in chimney design. A chimney cap and a chimney crown are installed to keep rain out of the top of the flue and chimney. Flashing is installed where the chimney and roofline meet, to keep water from getting in at those seams. And when brick and mortar are in good condition, they’ll provide some protection as well, allowing small amounts of water to seep in but expelling a lot more of it. 

It’s as the masonry in your chimney starts to wear that you have more cause for water worry. Masonry materials are porous, so even when bricks are freshly laid, they’ll absorb a certain amount of moisture. Over time, as weather and water take their toll — and cracks potentially begin to develop — bricks and mortar joints can start sucking up way too much water, even wicking it all the way through to the building materials behind them. This causes problems quickly, from leaks that accelerate the deterioration of your chimney to mold and frame and drywall damage inside your home.

The best way to help arm your masonry against that water intrusion is to have Northeastern Masonry & Chimney technicians apply a specially -designed waterproofing sealant.

Masonry Waterproofing Explained

Having a chimney waterproofing sealant applied isn’t just like slapping some latex paint on the masonry and calling it a day. This sealant is designed to repel water without negatively affecting the naturally porous properties of your masonry.

Masonry needs to be permeable, so that vapors and gases that are in your chimney can move through and out. A sealant that blocks water without letting the masonry retain that permeability would end up doing more harm than good.

Chimney waterproofing sealant, however, is designed to be 100-percent vapor-permeable, keeping outside water from getting in and allowing vapors to flow from the inside out.

Tech waterproofing chimney holding caulking gun-wearing a blue vest-dark clouds and highway in the background.

Waterproofing Brings Big Benefits

We’re always big proponents of preventative measures, since our priority is to help our clients enjoy their fireplaces and stoves as safely and efficiently as possible, while limiting the headaches that can come along with chimney damage. We’ve found waterproofing sealant to be a small and very valuable investment in keeping your chimney in its best shape — it extends the life of your masonry, makes leaks less probable and ultimately makes your life easier in the process.

If you’re interested in having a waterproofing sealant added to your masonry, call Northeastern Masonry & Chimney today, and make an appointment with our CSIA-certified techs!


Flashing problems may be the culprit when it comes to a leaky chimney and our trained crew can find the leak and fix it right!