Metal fireplace and chimney repair in Timberleaf

Offsets and elbows in the chimney

Factory-built chimneys can jog sideways with elbows, within limits. Section R1005.7 keeps every piece of a factory-built chimney within 30 degrees of vertical and allows four elbows at most in the run.

One maker's manual adds its own rules for the length of angled pipe between supports and for the straps that carry the weight above an offset. When a chimney has been rerouted, we check it against both before any repair.

What may touch the face of the fireplace

One maker's instructions allow combustible materials such as wallboard and plywood to meet the sides and top of the fireplace face, provided they stay off the face itself. Brick, glass, tile or other noncombustible materials may overlap the face if they leave louvers and other openings clear.

The same manual calls for noncombustible mortar or adhesive when a noncombustible facing overlaps the face. Refacing jobs that ignored those rules can cause trouble, and we check them whenever a prefab repair brings us to the surround.

• Wallboard to the sides and top, never over the face
• Noncombustible facing may overlap
• Louvers and openings left clear
• Noncombustible mortar or adhesive only

Ash removal from a factory-built firebox

Shoveling ash out of a factory-built firebox takes a little care, since the floor under the ash is refractory and hard scraping can chip it. One maker's manual asks for ashes to go into a metal container with a tight-fitting lid, placed on a noncombustible floor or the ground away from combustibles until the cinders are cold.

Chipped floor panels near the front often trace back to ash removal. We replace damaged floor panels during a repair and suggest a gentler routine for the next season.

What we can see and what stays hidden

Much of a factory-built system sits behind walls, above ceilings and inside a chase. From the firebox, the attic and the roof we can see a good share of it, and some stretches stay out of view.

The estimate lists what was checked and from where, and names any part of the system we could not see. If a hidden section needs a look, we explain the access it would take before anything is opened.