Due to pressure differences caused by stack e.
Insulation around chimney in attic.
Turn the water heater or furnace off and allow the flue to cool to the touch.
Holes hidden in attics basements and crawlspaces are much harder to locate and usually cause bigger problems.
After the air sealing work was complete including wiring vent and plumbing penetrations throughout the attic the attic received an r 60 blanket of blown cellulose insulation.
In hot climates it prevents heat from outside the house entering reducing the need to use air conditioners.
The b vent system requires air space clearance as well as clearance from combustibles.
Fibreglass is not considered non combustable correct.
For diy attic insulation you ve got two choices.
You can wrap the masonry with a 3 5 fiberglass batt and then blow cellulose up to the batts.
Fiberglass insulation is commonly used in attics around the chimney stack.
In either cse it fills the required open air space around the b vent in the un conditioned attic space.
How to insulate a metal flue pipe.
Once you ve decided which type is best for you examine the material options and prices to home in on the right product.
Both can be added to uninsulated attics or layered over existing material.
Because the pipe gets hot building codes usually require 1 inch of clearance from metal lues 2 inches from masonry chimneys to any combustible material including insulation.
Measure the circumference of the flue.
It is an effective barrier to the passage of heat.
Furnace flues require special sealing techniques the opening around a furnace or water heater lue or chimney can be a major source of warm air moving in the attic.
Don t you still need a 2 clearance to combustables.
Fiberglass is one of the most commonly used materials for insulating the home.
You can insulate around masonry chimneys after airsealing with mineral or fiberglass batts no foam or cellulose directly against the chimney.