Santa has a hard time in eastern Massachusetts. So many of our chimneys are in rough shape. Some are no longer in use, but stick out of our roof lines, nonetheless.  In truth, the big guy couldn’t come down a modern chimney, even one in good shape. They tend to be two-foot square, at best; that’s not even allowing for the liner that many modern chimneys have.

vent pipes

Efficient hot water heaters and steam/hot water home heating systems do not need a chimney. Their emissions are low in petrochemical pollution and are mostly water vapor. They vent through PVC pipes.

Santa doesn’t have a prayer…


If you are considering decommissioning your chimney, plan ahead

Hot water heaters last 6-12 years, depending on the quality of the heater you install. Your boiler (for steam or hot water home heating) lasts 25-30 years. When you replace your boiler, make the decision: chimney or PVC?

Here’s the rub: when your hot water or heat fails, you do not have the luxury of time to ponder your replacement. That is a vote for planning ahead.

Once your hot water heater hits its warranty date, start looking into your next hot water heater. Choose whether this is the time to move the plumbing, so that you can have a direct vent hot water heater, from now on. Pick your plumber, so you have them on the same page and ready to go when your heater, inevitably, dies. Plan ahead. Replace it before it dies, once it is beyond warranty.

Boilers for steam or hot water home heating are more expensive. They require more planning to convert to high-efficiency, direct vent systems. To do the best conversion, you should have an energy audit first, then you are eligible for rebates on your upgrade through Eversource. Consider doing this when your boiler is 25 years old, no matter how well it is working.


How chimneys age


The most short-lived part of a chimney is where it attaches to the roof. When the roof is replaced, every twenty years or so, a new flashing is installed to keep the water from flowing down the outside of the chimney and making its way under the roof shingle.

A flashing is a metal sheet that directs the water away from the gap where the chimney goes through the roof. Over time, that metal expands when it’s hot, contracts when it’s cold, and the metal finally cracks. This causes a leak around the chimney. It is either fixed by installing a new metal flashing, or tar is painted on top of the metal to seal up the little cracks. The tar fix will last two to five, or so, years. By then, maybe, you need a new roof and get a new flashing along with it.


chimney mortarThere are two layers of brick in residential chimneys. Most chimneys from before 1960 were built without a clay or steel liner. The air went up along the inside wall of brick. The mortar between the bricks corrodes on the outside by exposure to temperature changes and wetness. The mortar on the inside corrodes for the same reasons, plus from exposure to the chemicals in the smoke coming up.

Failed mortar, over time, can allow a brick to get loose. The brick can fall off the roof or into the chimney. Either is bad news. A falling brick can damage the neighbor’s house or hurt a person or animal in its path. A brick that falls into a chimney can block the flue and cause smoke and carbon monoxide to get into your basement. If you are home when a brick falls in, you’ll hear it. Otherwise, you’ll hear your CO detector when you get home.


chimney linerChimneys, by modern standards, are supposed to be lined. This prevents the possibility of smoke getting into the house if the chimney is blocked at the top or by a brick that has fallen in. Chimney insides can get pretty grubby.

House hunters, when you look at chimneys, don’t expect that there’s a fireplace. Most chimneys were built to vent heating systems. When you see the chimney, look for a liner. If it is clay, you’ll see it sticking out. If it is metal, you can’t see it. Also look for white pipes coming out of the basement. This would mean that the chimneys are no longer in use, and you have high-efficiency heating systems.


Don’t be concerned about brick deterioration. They live longer than we do, up on the roof, where they can dry out after every storm. Your basement bricks have a much harder live. But that is a story for another blog.

This is pretty normal:

crooked chimneyThese chimneys are typical of residential chimneys that are more than 50 years old.  Both need re-pointing. The one in front is beginning to twist and bend; it could start dropping bricks soon. The other one also has gaps that are easily visible. Unfortunately, chimneys like this are sort of typical around here.

Chimneys are generally ignored by homeowners until something happens. That something is either a falling brick or a dead boiler or furnace. Replacing a boiler will trigger a homeowner to bring their chimney up to code.

When homeowners add the cost of lining a chimney to the cost of replacing their boiler or furnace, many are opting for more efficient direct vent boilers and furnaces. The more efficient systems bypass the chimneys, so no liner is needed. With high-efficiency boilers and furnaces, there is less heat going out the vent. Because of that, they can be vented out using PVC piping, because it’s not so hot that it will melt.