How To Seal Around Chimney In Attic
I peeled it back to see if the gaps had been sealed with a fire rated air stop such as sheet metal or cementboard.
How to seal around chimney in attic. Because the pipe gets hot building codes usually require 1 inch of clearance from metal flues 2 inches from masonry chimneys to any combustible material including insulation. The chimney crown is the cement part on top of the chimney. It s usually the hardest place to air seal because the cramped space underneath the eaves where the roof rafters rest on the outer wall makes it hard to move your hands and head. It s a good thing you spotted that dirt which is proof that a draft is moving into the attic from.
The opening around a furnace or water heater flue or chimney can be a major source of warm air moving in the attic. With some inexpensive materials and a day s labor you can save lots of money on heating every year by sealing these holes. Can i also use the foam to seal around a sheet metal chimney that passes through the attic. Second the sealant works as a waterproofing agent and prevents leaks.
Chimneys made of stucco plaster stone and concrete also require sealing. Air sealing the wall plate around the perimeter of your attic blocks air from escaping around the outer edges of your home. These gaps around plumbing pipes light fixtures chimneys and other attic bypasses are hidden under your insulation. 2 many chimney leaks are from cracks in the chimney crown.
Air sealing a flat attic and upgrading the insulation with a blanket of blown cellulose is bread and butter work for weatherization contractor matt damon and his company penobscot home performance based in bucksport maine. Among the many air leakage points damon and his crews commonly encounter in an older maine house is the open chase around the brick chimney. The thick layer of fiberglass insulation that covers our attic floor was tightly packed around the chimney. Air sealing the attic perimeter.
You can see that the very purpose of the chimney crown is to keep rain out. Many building codes require a. With time brick chimneys are affected by cracks and spalling and these deteriorate within a short period of time. Furnace flues require special sealing techniques.
Sealing an air leak around a chimney in the attic.