Chimney Chase Repair in the Seattle Area, WA.

Plenty of houses built here from the 1970s onward do not have a masonry chimney at all. They have a factory-built metal fireplace with a metal flue, and around that flue a chase: a framed timber box clad in siding, stucco or sometimes a thin brick veneer, built to make it look like a chimney. It is lighter, it was cheaper to build, and almost nothing written about masonry chimneys applies to it.

What fails on a chase is the chase cover – the flat metal lid on top that the flue pokes through. Most were made from thin galvanized steel, and most were made flat. Flat means water sits on them, and thin galvanized steel that holds water rusts through, usually somewhere between fifteen and twenty-five years. Once it is through, everything that lands on the chase goes straight down inside a wooden box that has no way to dry out. The framing rots, the siding below starts to show it, and the ceiling under the chase stains.

The giveaways are rust streaks running down the siding from the top, a sagging or ponded lid, and staining inside at the top of the fireplace wall. The repair is a new chase cover made from stainless steel, cross-broken so it sheds instead of ponding, with a proper collar around the flue and a drip edge over the sides – plus whatever framing or siding below it has already been damaged. We also check the storm collar and the cap on the flue itself while the lid is off.