Why chimneys lean

A leaning or tilting chimney is an unsafe chimney. Chimney repair and rebuilding services performed right after you notice a shifting can remedy the problem, restore your chimney to safety and save you a lot of money. Masonry damage: Age-worn and decayed bricks or missing sections of bricks and mortar can unbalance a chimney and result in the upper portion of it leaning.

Without a footing, chimneys are prone to begin tilting at one point in their lives. Insufficient or inferior footing: If the chimney footing is too narrow or shallow, it may crack under the weight of the chimney. Footings built with inferior materials also are more prone to cracks. Disclosure: BobVila. You agree that BobVila. All rights reserved. Expert advice from Bob Vila, the most trusted name in home improvement, home remodeling, home repair, and DIY.

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Find Pros Now. More From Bob Vila. It is a reality that needs to be addressed sooner, rather than later. If you look at the side of your home and see what looks like the Leaning Tower of Pisa , you definitely have a problem. A leaning chimney is a serious structural problem that should be dealt with immediately. You may not relate the summer season to the use of your chimney, but it is the best time of the year to make repairs and get ready for the cold winter that will be approaching.

Why you ask? I will name just a few imminent problems you can expect, other than the most severe - your chimney falling over. The bricks could fall on someone's head or crash onto your roof. Water and bugs could get into the gap where the chimney has pulled away from the siding. The chimney liner may be cracked, leaking combustible gases into your home, creating danger for your family. And since the chimney is probably connected to the foundation, there could be problems there, too.

All brick chimneys lean away from the sun. After years of being heated and expanded on the sunny side, they yield to the heat expansion ever so minutely each year.

By the time you notice this slow movement, decades may have passed. Take a look around your chimney from time to time! In addition to the damage caused by your shifting chimney, the space it used to occupy will be left open. Even a small gap can put your home at risk, and it will increase in size over time. The larger the gap, the more likely it is for moisture or other damage to invade your home from this new, vulnerable spot.

Every leaning chimney is a little different, but there are a few common causes that lead to them. The concrete underneath your chimney is critical to its stability. With the thousands of pounds of brick resting above, the concrete needs to be sturdy with properly installed rebar to support it.

The moment that this foundation begins to fail, it sets off chain-reaction where it will continue to crack and fall apart until your chimney crashes down. During harsh winters , the freeze-and-thaw cycles also cause significant damage to an existing foundation.

In some cases, chimneys may lean from the top. In most cases, this happens to chimneys venting gas from oil appliances. The cause is due to sulfur in the oil mixing with water.

When it condenses, it forms sulfuric acid that damages and deteriorates the mortar and promotes swelling from moisture.

Taller chimneys present with a more visible lean.