Chimney chase cover replacement in Springfield by local pros

The raised collar around each pipe hole

Each pipe that passes through a chase top gets a collar: a short upright ring formed around the hole, so water crossing the top has to climb over it before it can reach the opening. One maker's drawing calls for a 2-inch collar that is soldered, welded or spun, rather than a separate ring stuck on with caulk that can fail. The collar's inside diameter follows the pipe's listed outside diameter plus the clearance the manual gives. We make the collar part of the top itself, so there is no seam at its base for water to find, and we check its height with a rule before the top goes up.

Folded, welded and sealed seams

One-piece chase tops have seams only at their corners, where the skirt folds down. A very large chase, or one with an unusual shape, may need two sheets joined across the top.

Every seam is a possible leak, and fireplace manuals call for caulking all seams on the chase top. Corner seams are folded so water runs over them rather than into them. Joints across the top are folded and locked or welded, then sealed, and placed where water runs across them rather than along them. Fewer seams in the flat means fewer places to fail, which is why we cut one sheet where the chase size allows.

Testing the new top with water

A new chase top is shaped to drain, and water is the simplest proof. Where the roof gives safe footing, a garden hose is run over the finished top, first at the collar and then outward toward each edge, while we watch where the water goes. It should leave from every side and drop off the drips without standing anywhere.

If an attic hatch or access panel gives a view into the chase, someone watches inside for drips at the same time. Any top that holds water is reshaped on the spot, and the test result goes on the paperwork we leave with you.