Let's try to not heat exterior masonry.

[Smoked]

Reading some posts about block-off plates makes me question ways to take it one step further. I hate the thought of radiant heat from my stove heating up the firebox and adjacent exterior masonry and I would really like to try to do something about it. Here are some things that I have heard hear or have thought about.

Line the inside of the firebox with Roxul and paint it to trap the fibers and also make it less hideous looking. Would this really work or will it just trap heat?

Roxul rock board. Probably easier to make a nice looking install, but again, is this just going to suck up heat and trap it?

Sheet metal. If you paint it black, will it reflect heat or just suck it up too?

What if you built a false wall behind the stove spaced out from the fire brick. Would the radiant heat from the stove heat that mass up and then convection from it would be directed out by the block-off plate??? Something like this could be spare bricks stacked up or scraps from a granite shop. Maybe even heavier gauge metal?

I would want it to look natural or more or less invisible but still add value and not keep the bushes beside my chimney warm in the winter

Any other cool ideas???

 

[Jan Pijpelink]

I have an exterior chimney with a liner.
The liner is about 22' long. The top half is insulated with Roxul since last year. Tomorrow the lower half will be insulated.
I have been measuring with an IR the temp the indoor chimney wall and outside wall of the masonry chimney last season.

The T on the inside wall of the chimney was anywhere between 76 and 80 F on all 3 floors of the house. Outside it was constant ambient + 10 F.

I have asked the question using Roxul type board covered with SS sheet to use a block off plate. Experts on this forum advised me to use the metal sheet only (in combination with Roxul wool) and not use the Roxul board.

Does this help?

 

[Grisu]

This thread may help: https://www.hearth.com/talk/threads/finally-got-around-to-insulating-my-fireplace.75755/

 

[Smoked]

This thread may help: https://www.hearth.com/talk/threads/finally-got-around-to-insulating-my-fireplace.75755/

Thanks! Insulated cement board seems like a good plan.

 

[mellow]

Sounds like this is for a rear vent freestanding stove? I would just make a false wall out of concrete board and cover it with tile. I wouldn't worry about a block off plate if you are just piping it to a tee in the firebox, make the false wall so it splits in half.

 

[Smoked]

Yea, I could do that with one. Thought about sheet metal but I could do something really nice with tile to that will go in the keeper stack! The basement install is set back in the fireplace a bit so it would be a little more complicated. I know pipes are for venting and not heat but I would hate to lose the heat off the snout and tee too. Block-off plates are both in so that is done. I am looking forward to see if I can tell any difference in the living room install from that alone. The basement install is new and will be used mainly for the really cold spells.