Everyone knows that water is very damaging. It erodes earth and rock, carry away large pieces of land during mudslides, and it wreaks havoc on your masonry chimney. We don’t see the damage every time it rains, but it slowly creeps up until the damage is so extensive we have to spend a lot of time or money on chimney repair. Today we’re going to talk about three ways water destroys your chimney and how to minimize the damage.

Rusty Parts

The damper and a few other working parts of the interior of the chimney are made of metal. Water rusts metal, and often at a rapid pace. Rust will cause the damper to lock up and prevent it from performing its normal functions. You may not see rust right away but notice that the damper is increasingly difficult to open and close – these are signs of rust. Rain water often enters the chimney through the flue opening if there is no chimney cap.

Avoid rusty chimney parts by installing a chimney cap and making sure that the chimney crown is properly sloped so that it whisks water away from the flue. Chimney caps are generally made of metal, and some are very decorative. Consider having a custom chimney cap designed for you if you really want your chimney to be unique compared to others in the area.

Flaky Masonry

You’ve probably seen damaged brick that appears to be flaking off in chunks. This process is called spalling and it is caused by serious water penetration. A chimney cap can only help so much against spalling. Rain water and snow melt generally drain off of the chimney cap and onto the chimney crown. If the crown isn’t performing its job correctly, it will allow water penetration.

Avoid spalling by making sure the chimney cap is in place and the crown is properly angled. The chimney crown plays a more serious role in preventing severe water penetration simply by its shape. Water takes the path of least resistance, and the chimney crown should be angled away from the flue opening in such a way that it becomes the second barrier against water penetration. The first barrier would be the chimney cap.

Mortar Erosion

Your chimney is attacked by extremes from all directions. It sees extreme weather from the outside and extreme heat from the inside. This process causes serious problems with the mortar that holds the brick or stone together. Eventually rain water and wind cause serious erosion in the mortar and if left untreated, it will become thin and eventually break apart, causing the chimney to crumble to the ground.

You can’t necessarily avoid erosion entirely but you can slow it greatly. Apply masonry sealant to the entire chimney at least every couple of years for best results. High quality sealant will penetrate the masonry and protect it from the inside. Use a breathable sealant that will keep water out but allow trapped water to evaporate. Repointing a damaged chimney may become necessary if the mortar erodes more than 1/8” or if you can easily see deep valleys between the brick or stone.

Yearly Inspections

A yearly inspection helps in more ways than many homeowners realize. Certified Chimney Sweeps are trained to specifically notice the small things that homeowners don’t see over time. Something that looks perfectly normal on a day-to-day basis may end up being a serious issue that needs to be addressed if it is noticed by a chimney sweep.

The Chimney Safety Institute of America (CSIA.org) recommends that chimneys be inspected and cleaned at least once per year. Chimneys that see a lot of use (daily during the winter and sporadically throughout the year) should be cleaned and inspected twice per year. Call Lou Curley’s Chimney Service at 610-626-2439 if you’re in Delaware County, PA or the surrounding area.