I have come across this a few times. A person purchases a thirty-year-old house that has been completely updated. Then the question about chimney caps comes up. For instance if your home inspector says that the chimney does not have a cap and it’s ok he may not be correct. Even if the chimney is not in use for one reason or another, for example the last owner did construction or had a professional construction company take out the chimney from the inside or it used to be a part of the water heater but is no longer used. It seems like you wouldn’t need a chimney cap correct? Well let’s first find out what a chimney does to find the answer first.
A chimney cap is a defensive covering for chimneys that are usually made of aluminum, galvanized or stainless steel, or copper. These are the main things a chimney cap does:
1) Keeps Out Moisture
The most basic purpose of a chimney cap is to avoid rainfall from inflowing your home. Dampness is the supreme enemy to a chimney and causes most of the corrosion that occurs over time. This is why a chimney cap is needed no matter what. Used or unused you need to keep the rain out of your chimney opening. Rain can do massive damage to your home for instance it can soak into the masonry and create mold. This is bad.
2) Keeps Out Animals
Most caps have a screen. The function of the screen is to prevent animals from getting inside the chimney or other big objects. It is not uncommon for squirrels, snakes, raccoons, birds, and other creatures to be drawn to the warmness of a chimney and climb in. Birds will often build nests in chimneys. You can imagine what a mess this is.
3) Blocks Hot Embers
A chimney cap with a mesh screen is also useful as a spark arrestor. Hot embers and sparks that could possibly start a fire on the roof or other nearby combustibles are blocked from escaping the chimney. This may not be important to you if your chimney is not is use but it’s one of its main purposes none the less.
Even if you choose to not permanently close your chimney (with concrete or the like) you must maintain your chimney cap. Many home owners make the mistake of thinking that there is no upkeep for them. But, it so happens that maintenance is crucial and can be very simple.
Without proper maintenance the screen on the cap can become clogged. You can image the dangers this can produce because not only do the fumes and smoke get no get out but they can get stuck and be pushed back into your home. This can also cause a fire hazard. Even if you do not use your chimney with a clogged cap moisture will not be able to dissipate and we already know the damage that moisture can cause your home. The good thing is maintenance is as simple as dusting off the cap with a broom. So please do this at least once a year.