Attic insulation question

[Alexander Galkin]

I am adding insulation to the attic that already has insulation. I have a heater chimney that goes through the attic. Can I use John Manville Kraft R-19 unfaced batts to add insulation to the attic? The package says its for wall/floor/crawl spaces. I assume it can be used for attic too. Can batts touch heater chimney? The chimney actually has two pipes, one inside another. The inner pipe is very thin aluminum pipe while outer pipe is regular duct metal pipe. If batts cannot touch chimney can I use thermofiber insulation around the chimney and keep batts 3" away from it? I think thermofiber insulation does not burn and can touch hot objects.

[jake]

Try Roxul http://199.202.236.133/usa/english.asp

[Phisherman]

[Alexander Galkin]

Can't chimney get hot enough to cause fire of it touches unfaced batts? The insulation pack I bought says to keep it at least 3" from hot objects: chimneys, fireplaces, non-IC recessed lights, etc.

[George E. Cawthon]

What is a heater chimney? you mean the chimney for a furnace? Most metal chimneys are not zero clearance and generally require a 3 inch clearance. You treat chimneys just like you do sunken light fixtures (ones that protrude above the ceiling). You build a ring of sheet metal around the fixture to keep insulation or other material away from, or in this, case the chimney to a height slight greater than the depth of the insulation.

And no, you do not wrap any k>

[Alexander Galkin]

The chimney was used by both furnace and gas heater before I replaced the furnace with 92% furnace that has now separate PVC pipe chimney through the basement wall. The old metal chimney is used now only by gas heater. The chimney consists of two pipes: light aluminum inner pipe and heavier metal outer pipe. The chimney goes from the basement to the roof through vertical square opening. The opening is larger then round chimney (outer metal pipe) and warm air is sucked away from heated insulated basement and cold air is sucked in to the basement from the attic. So this void space around the chimney outside pipe must be closed somehow with insulation.

[George E. Cawthon]