How to Insulate My Triple Wall Stove Pipe

Measure the depth of the existing insulation in your attic around your triple wall pipe. Purchase a short section of single wall stove pipe with a diameter 2 inches longer than the outer diameter of the triple wall pipe you intend to insulate. Cut this section of pipe so that its length matches or exceeds the depth of your insulation. Cut the single wall pipe in half down its length using the tin snips.

Drill holes at the top and bottom of the two sections of single wall pipe 1/2 inch away from the top and bottom corners of each section. In the attic above your stove, clear away any insulation around the stove pipe that is less than two inches away from the stove pipe. Place the two halves of the single wall pipe standing up around the triple wall pipe so that they separate it from the surrounding insulation. Push the edges of the pipes together so that the holes you drilled overlap and fasten the pipes together using the sheet metal screws.

Install insulation made from mineral rock wool in the gap behind the metal ring to make sure that the heat from the pipe does not melt the insulation around the metal ring. Only install enough insulation to cover the outside of the metal ring without spilling over into the space around the triple wall pipe.

Make sure that the metal flashing above the roof is secure and seal any air gaps between the pipe, the roof and the flashing using heat resistant caulking. Make sure you maintain at least two inches of clearance between the triple wall pipe and any flammable materials.

Insulate the space between the triple wall chimney and the roof using a metal collar sealed with heat resistant caulking. This will prevent unconditioned air from the attic from leaking into your home through the gap in the ceiling around the triple wall chimney pipe.