Remodeling and Tapping Into Chimney- Insulation, Barriers ?

User avatar
Posts: 1446
Joined: Wed. Jan. 19, 2011 11:41 am
Stoker Coal Boiler: Keystoker KA-6
Hand Fed Coal Furnace: old Sears rebuilt, bituminous- offline as of winter 2014
Coal Size/Type: Anthracite Buckwheat
Other Heating: Oil Boiler
Location: Western PA

Post By: CoalisCoolxWarm » Wed. Nov. 11, 2015 12:47 pm

Okay, after much googling (not the poolside kind, LOL), I think I am going to go with a clay liner and 12" clearance. See the rendering below.
Stove is 31.1" from floor to top of flu. I didn't account for any hearth yet, just wanted an idea. Tried to maintain 18" from ceiling, although I will likely add a 1" standoff metal plate, just for extra care.

12" to sides don't measure up properly. I guessed at thimble size and thickness. I overestimated, but hard to change in the dwg.

Double wall, insulated, super-duper, fancy-pants through wall setups are about $300(!) Sure, they list the thimble and the cover separately, but it requires both and adds up to about 300 smackers :shock:

I'm opening and redoing the wall anyways, not a big deal to make the clearance. Probably be better to have more open area when drilling into the chimney anyways ;)


1. What do I use in the wall to support the thimble? Strapping? Aluminum flat stock?

The wall will be something like 6" thick, plus the chimney block into the liner and whatever spacing is between outside wall of house and the chimney (maybe and inch or so?)

2. Can I fill this 12" spacing with Roxsul? The requirements are 12" clearance from COMBUSTIBLE materials, so maybe this rockwool is okay?

Don't want an uninsulated "refrigerator" in the middle of the wall when not using the stove, Lol. That's also why I don't want to go with the monster brick square entrance.

3. Load bearing considerations. Guess I'll have to make a header and all that jazz, since this is an exterior, load bearing wall? It's only one stud???

Any input, suggestions, links are all appreciated!

Post Reply

Return to “Coal Bins, Chimneys, CO Detectors & Thermostats”