Local chase cover replacement for Washington Shores homes

Sheet thickness and why it matters

Thin sheet metal flexes under its own weight, under debris and under a worker's hand, and a sheet that flexes eventually dishes and holds water. Fireplace manuals set a minimum thickness for field-built chase tops, and heavier sheet holds creases and pitch better on a wide chase. The estimate names the gauge we plan to use so you can compare it with another proposal, since two covers can look alike from the yard and differ a great deal in stiffness.

What we check while the top is open

The time the cover is off gives the only full view of the chase top, so we use it. Findings are recorded in writing, and anything outside the cover replacement is priced as its own item for you to approve or decline.

• The outer casing of the chimney pipe, for rust or damage
• The joints where pipe sections lock together
• The edges of the framing and sheathing at the top
• Debris, nests or wet insulation inside the enclosure

Brick-faced chases around a metal chimney

Some homes have a factory-built chimney inside a chase faced with brick or stone veneer. The lid over that enclosure is still a chase cover, and it still needs a collar, a slope and a drip edge. The top edge of the veneer is often uneven, so the skirt is sized to its highest points. We also check whether the top of the veneer is sealed or open, because water entering there follows a different path than water through the cover.

Why the old cover is never used as a pattern

Tracing the old cover looks like a shortcut, yet a rusted, dented cover has usually moved from its original shape. Its collar may be off center, and it may have been undersized from the start. We measure the chase and the pipe position directly. The old cover is useful only as a record of what failed, such as where water pooled or which seam opened first. Those clues tell us where the new top needs more slope or a stronger seam.