What is the leak test procedure for a chimney tray or chase cover?

What the tray is

Many Georgia homes built in recent decades have a framed chimney: a wood box covered in siding that houses a metal flue. The top of that box is closed with a metal pan, called a chase cover, chase pan or chimney tray, with a hole and a storm collar where the flue passes through. Builder-grade galvanized covers are often flat, so water sits on them until they rust through.

The test, step by step

1. Start dry. Pick a dry day and check the attic or the access panel inside the chase first, so new water is easy to spot.
2. Zone 1, the roof flashing: run water low, where the chase meets the shingles, for 10 to 15 minutes.
3. Zone 2, the siding: wet the chase walls, corners and trim, without aiming up under the laps.
4. Zone 3, the tray edges: run water along the perimeter where the cover bends down over the siding.
5. Zone 4, the center and storm collar: flood the top of the cover around the flue.
6. Note which zone first produces water inside, and photograph it.

Let the hose run gently rather than spraying hard. A pressure stream forces water where rain never goes and gives a false result. Use proper fall protection or leave the roof work to a professional.

What a failed test usually means

• Water at zone 3 or 4: a rusted, cracked or flat cover, or a failed storm collar seal. The lasting fix is a stainless or heavy aluminum cover with a slope or cross break, a drip hem that extends past the siding, and a sealed storm collar.
• Water at zone 1: step flashing, or the cricket behind the chase.
• Water at zone 2: siding, trim or housewrap, which is siding work rather than roofing.

See chimney leaks and crickets and common roof leak causes.