Keeping the April Showers Out!
Water infiltration is a big deal for masonry chimneys. Water can enter masonry and erode mortar joints, decay brickwork, and when it freezes it can split crowns and brickwork apart. Water can also enter through chimneys and flashing and rot and decay the wood structure of your home. Keeping water outside where it belongs can be a very difficult task, especially on older New England homes.
Having a proper chimney crown can be a major help. A properly built crown extends beyond the brickwork of the chimney to move rainwater away from the masonry. It overhangs much like the eaves of a roof do on your home. Still, most masonry chimneys have what’s known as a wash, which like a crown is a concrete top on a chimney, but unlike a crown it doesn’t overhang. Instead, water runs to the edge and then down the brickwork, possibly leading to infiltration into the chimney. Repairing a damaged wash will help to keep water out, but if at all possible pouring proper crown will make a big difference.
Flashings are also very prone to leaks, especially when improperly done. When budgets are tight but repair is needed, a flashing sealer can be an effective and inexpensive solution to keep water out. Flashing sealer is a paint on rubber layer which lays over top of the flashing like a big rain coat. It dries quickly and is pretty effective at keeping out rainwater.
Finally, make sure you have a cap installed. Caps do wonders to keep rainwater out of the flue interior which greatly helps extend the lifespan of your masonry flue. This is especially important on a flue serving an oil appliance.
Enjoy the great weather and watch out for the black flies!