By Lawrence Englehart, GPI Franchise Owner, Halifax, Nova Scotia
Most people would be surprised to know that Nova Scotia gets an average precipitation of 1,388 mm per year — which equates to more than 54 inches of water hitting the ground, roof and chimney each year — so keeping water or excessive moisture out of our homes can be a constant battle.
Regardless of where you live, when it comes to typical penetrations of the roofing system, the chimney offers the most opportunities for water to make its way into the home. Here are examples of the four common causes of chimney-related leaks:
Flue pipes come in many sizes, but 8”x8” or 8”x12” clay liners are typical, providing a large opening for water to get inside. If rain is allowed to freely flow down an open flue pipe, it will mix with soot or creosote and can create unsightly stains. A properly designed rain cap will not only minimize water entry, but it can help keep leaves and critters out.
Masonry Cap or Crown
The chimney cap or crown is a cement cover placed on top of the masonry chimney in an effort to shield the top of the bricks from the elements. A properly designed masonry cap should overhang each side by at least two inches and should gently slope away from the clay liner. Visible cracks or a poorly designed masonry cap could allow water in.
The mortar between the brick will naturally deteriorate over time and will eventually need repointing. Repointing is the process of replacing the old mortar with new. Any visible gaps or cracks in the mortar will allow water to enter these voids and can cause significant damage through multiple freeze/thaw cycles.
Chimney flashing is designed to prevent water intrusion from where the chimney passes through the roof. Visible signs of excessive tar cover usually suggest past problems with leaks and nonprofessional installation. Sometimes the best place to inspect for flashing failure is from inside the attic space.
The inspection of a masonry chimney is part of a typical home inspection, but once they take possession of their new home, most homeowners never think about regular chimney maintenance. Your masonry chimney should be inspected each year by a qualified masonry contractor. And, if there are any wood burning stoves or fireplaces attached to the chimney, then your chimney it should be cleaned and inspected by chimney sweep. In Canada, your chimney sweep should be a WETT-certified.