How the Freeze-Thaw Cycle Can Ruin Your Chimney


When winter’s deep freeze has taken hold for months, nothing can seem more glorious than a bright, sunny day. It warms the roadways and rooftops as the snow melts away. But when the temperature drops again, that temporary thaw can have a detrimental impact to masonry materials, including your chimney. Here’s what you need to know about the freeze-thaw cycle and how you can protect your chimney from it.

How the Freeze-Thaw Cycle Damages Chimneys

When water freezes, it expands. That’s dangerous because water from melting snow or an unexpectedly warm and rainy day penetrates the masonry chimneys. When the water inside freezes and expands, it causes the masonry material to crack.  That leads to crumbing mortar, large cracks in the chimney structure, or the popping off of the faces of chimney bricks.

The initial impact of the freeze-thaw cycle is aesthetic — a crumbling chimney certainly doesn’t improve the look of your home! Freeze-thaw damage and effects become more serious over time. The cracks allow water to find its way into the chimney interior, where it can cause deterioration or rusting and damage within the fireplace. Water can also make its way into your home, rotting away at your home structure while causing water stains, sagging ceilings and mold growth. For the chimney, the continued breakdown of the masonry materials due to freeze-thaw damage can compromise the entire chimney structure. The chimney can start to lean, become unsound and unsafe, and eventually collapse altogether.

How to Protect Your Chimney From Freeze-Thaw Damage

How you protect your chimney from freeze-thaw damage will depend on whether or not your chimney has already been affected. If your chimney mortar and bricks have already started to crack and crumble from alternatively warm and freezing temperatures, repairs will be to restore the look and function of your chimney. Cracks in chimneys need filled. If mortar is weak and crumbling, tuckpointing might be recommended. Tuckpointing involves the removal and replacement of weakened mortar to reseal chimney joints.

If your chimney hasn’t suffered damage, you can protect it from the freeze-thaw cycle with waterproofing. Waterproofing involves applying a solution to your chimney’s exterior masonry. The solution prevents water from entering the chimney’s masonry while still allowing the chimney to exhaust the smoke and gases from your fireplace. Ultimately, waterproofing can save your chimney from expensive deterioration due to freeze-thaw and other water damage.

If your chimney has suffered visible freeze-thaw damage, call Total Chimney Care to schedule an appointment! Our chimney experts can restore the appearance and the security of your chimney and help protect your chimney from future damage.

By on February 9th, 2018| Tagged with: Tags: , , | Leave a Comment