AMONG THE CHIMNEY TOPS

“A cheyer byfore the chemné, ther charcoal brenned, was graythed for Sir Gawan”[1]

Writers have long understood how palpable the image of the fireside is. Who doesn’t love the feeling of sitting down in front of a hot fire on a cold night after a long day? Arguably, the appeal of these specific circumstances is hard-wired into the human consciousness: warmth, security, the closeness of rest.

Yet, these are tough times for chimneys. A short history lesson will explain why.

Before the post-World War II building boom, fireplaces were a primary source of heat for most homes in the winter. Sure, furnaces of some type or another have been around for quite a while, but in colder climates many houses had a fire burning almost daily from fall to spring.

A chimney in need of repair.

A chimney in need of repair.

Today, however, most new houses and town-homes do not have the large-scale masonry chimneys. Appliances that make heat through combustion still need to be vented, but this is often done with much smaller metal and even PVC plastic chimneys and vents. Massive masonry chimneys are expensive to construct and, as a primary source of heat, are virtually obsolete. Some chimneys get regular use through the winter months, but most are used sparingly, if at all.

This is where the trouble starts. Think about anything that sits unused for a while. You know intuitively that there’s a pretty good chance something will go awry the next time you use it: lawnmowers that sit all winter, window unit air conditioners that molder in the garage, that bike you haven’t taken out in a while … that pair of pants that’s been in the back of the closet for a couple years. (Don’t ask)

Notice the loss of mortar between the bricks at the top and in the right side wall.

Notice the loss of mortar between the bricks at the top and in the right side wall.

Because most chimneys don’t get regular use, maintenance issues arise that might surprise our hearth huddling forefathers. When chimneys were channeling vast volumes of hot air from October to March, they stayed nice and dry. Nowadays, the chimney that only sees action at Christmas suffers damage from the wet weather because it’s not warm and dry.

Brick, mortar, and porous stone can absorb water. This means that something has to keep rain and snow from seeping down through the masonry.[2] Many chimneys are topped with what is called a wash-cap. The wash-cap is a relatively thin layer of concrete the mason spreads over top of the last row of bricks to keep water out.

There is nothing to keep rain and snow from coming down the flue of the chimney on the left.

There is nothing to keep rain and snow from coming down the flue of the chimney on the left.

Like any exterior component, wind and weather wear away masonry over time. Wash-caps are no exception. The majority I see are covered with cracks or are crumbing. When this happens, water has a direct path into the chimney, and frequently through the roof. Don’t forget that many chimneys are a hole in the roof; an intentional one, but a hole nonetheless.

So what do I look for when I inspect chimneys? Whenever possible, I look at the top itself and assess the condition of the metal weather cap (if present) and the wash-cap. I also look for mortar deterioration and water stains. These are consistently signs that a cap has failed. As you can see from the pictures, these aren’t difficult things to identify.

Signs of a failed wash-cap? Notice the water stains at the top of the chimney.

Signs of a failed wash-cap? Notice the water stains at the top of the chimney.

What is the remedy for damaged chimneys? The first step is to call a qualified chimney sweep. No, these folks don’t run around in top hats and carry shoddy brooms. Modern chimney sweeps use as much digital equipment as any other trade. When I see damaged chimneys, I often recommend a level two inspection. This involves sending a camera into the flue to look for hidden damage. Bottom line: a chimney inspection will give you a much better idea of the scope and scale of the damage as well as direction toward resolving any issues found.

Compared to the cost of water damage, a chimney inspection is very reasonable. As for the cost of repairing a chimney itself, it varies a lot: extent of the damage, size of the chimney, materials used, and accessibility are all factors. I love sitting by the fire on a cold night, but sometimes the most reasonable option is to just have a chimney capped. Many roofing companies can do this. The cap can always be removed later if you want to do a full a repair and put the chimney back into service. For chimneys with minor damage, many homeowners upgrade to a masonry-cap as opposed to a wash-cap. A masonry-cap is a preformed piece of concrete that is much thicker than a wash-cap and sheds water like a mini roof.

Like windows and doors, chimneys are an opening to the outside, and as such they deserve just as much attention.

– Joe

[1] “A chair was arranged for Sir Gawain before the chimney where charcoal burned” – Sir Gawain and the Green Knight, late 14th C.

[2] The flue is the hollow vertical space through which smoke ascends. The chimney is material on the outside of the flue(s). Individual chimneys can, and typically do, have more than one flue within them.