Home>Discussions>INSULATION & HVAC>Insulating around a chimney
3 posts / 0 new
Last post
Insulating around a chimney

I live in a cape cod in Northern Illinois. The brick chimney that is used to vent the gas furnace and water heater runs through the interior space of the house. The walls built around the chimney are completely uninsulated.There is also an open air gap between the chimney all of the floors. I can see from the basement to the attic.

Should I be filling this gap between the chimney and the rafters or will this create some sort of moisture issue.

Also, I have already insulated the walls that surround the chimney in a room upstairs with ridged foam insulation and did not disturb the airspace between the chimney and the back of the wall (approx 1 1/2" - 2"). Will this cause any moisture issues?

Any advice would be appreciated. My first child is on the way and I want to make sure that room upstairs is not a icebox in the winter.

Re: Insulating around a chimney

To my understanding the space was left around the chimmney originally because the old heating equipment heated up the flue. Chances are you should have new flue liners inside which shouldn't heat things up. You should be able to seal up the space with something like mineral wool insulation.
What I've learned here and other sources is air space behind the insulation is not good.

Re: Insulating around a chimney

Thanks for your input. It is appreciated.

Sponsored Stories

TV Listings

Find TV listings for This Old House and Ask This Old House in your area.