Flashing is a thin strip of corrosion-resistant metal or membrane installed at joints in a masonry wall, such as where a roof meets a chimney or a wall meets a window, to intercept water and direct it back outside instead of letting it soak in.
Masonry moves water constantly, off roofs, around windows, and down chimneys, and every place two different materials meet is a spot where water can find a way in. Flashing bridges those transitions: step flashing climbs a sloped roofline against a chimney, cap flashing tucks into a reglet cut in the brick above it, and window flashing sheds water off a sill before it reaches the wall below. Done right, it's invisible. Done wrong or left out, water tracks behind the masonry face for years before anyone sees a stain.
We see the most flashing failures on older chimneys around Hillsville and Galax, where the metal has rusted through or was never properly stepped into the brick. Once that seal opens, water gets behind the masonry and the freeze-thaw cycle takes it from there, cracking mortar and popping brick faces from the inside out. Replacing worn flashing during a chimney repair is one of the cheapest ways to stop that damage before it spreads.
More masonry vocabulary from the glossary.
The services where this term comes up.
Chelo's Brick & Stone serves Hillsville, Galax, Wytheville, Fancy Gap, and Independence, VA. Call for a straight answer and a free on-site estimate.
