Barbara Miller
09-26-2011, 09:04 AM
Hello,
Our basement water heater vents out of what used to be a gas furnace flue through our attic (we now have a furnace that vents out of our basement.) I notice that even when the water heater is heating, the 8" or 10" duct hardly feels warm up in the attic.
My plan was to make a jacket out of flashing to keep our attic insulation at least an inch away from this duct, but since it doesn't get hot, I am wondering if (non-combustible) Roxul mineral wool could be used right up against the duct.
I will check with our local MA plumbing inspector, but since codes sometimes don't make such distinctions, I am curious about whether, for all practical purposes, my rationale makes any sense or whether there are other issues to consider. I did air seal the utility chase where this duct is located at the attic and basement levels, with flashing and intumescent caulk.
Thank you for any comments.
Our basement water heater vents out of what used to be a gas furnace flue through our attic (we now have a furnace that vents out of our basement.) I notice that even when the water heater is heating, the 8" or 10" duct hardly feels warm up in the attic.
My plan was to make a jacket out of flashing to keep our attic insulation at least an inch away from this duct, but since it doesn't get hot, I am wondering if (non-combustible) Roxul mineral wool could be used right up against the duct.
I will check with our local MA plumbing inspector, but since codes sometimes don't make such distinctions, I am curious about whether, for all practical purposes, my rationale makes any sense or whether there are other issues to consider. I did air seal the utility chase where this duct is located at the attic and basement levels, with flashing and intumescent caulk.
Thank you for any comments.