Rain is a big deal when it comes to fireplaces and chimneys. As the Chimney Safety Institute of America explains, “water, not fire, causes most chimney damage.”
“Whether masonry or factory-built,” says the CSIA, “prolonged water exposure can result in cracks or gaps in chimneys where creosote can collect and increase the risk of fire or where noxious gases can escape into your home and expose your family to carbon monoxide.”
Fireplaces, Chimneys, and Leaks
In basic terms, the problem with fireplace and chimney leakage is that water combines with the creosote that remains from fires to form an acidic mixture. Over time that mixture can eat out the silica in the mortar joints.
Once the joints are no longer secure, moisture — remember all that Gulf Coast rain — can get into the house through the chimney. For example, if water comes in through the chimney and is released under the shingles it can lead to the need for a roof replacement.
Also, without proper sealing, heat from fires can travel into areas that should not be exposed to heat, dry out the wood, and in some cases actually cause the wood to catch on fire.
In fact, according to a staff report by the US Consumer Product Safety Commission, there are about 22,000 fires a year which are associated with fireplaces, chimneys, and chimney connectors. Such fires can cause substantial damage and in some cases may lead to fatalities.
Also, without caps, it does happen that birds and animals get into fireplaces. Sometimes nests are built and in some cases, animals unable to get out die inside chimneys and fireplaces. Noises and odors can result from such problems.
Caps, Covers, and Dampers
You can protect your household with caps, covers, and dampers.
Caps with spark arresters are devices that go over the flue. They keep out both moisture and animals, plus they help prevent sparks from leaving the chimney.
Covers are at the top of the chimney, go around the flue, and protect against moisture.
Dampers are inside the chimney itself. They can help create a proper draft to achieve the best fire, plus when closed they prevent animals from getting into the house.