Building a thermal mass around woodstove new construction

Hello all,

First post here and complete noob regarding this field. I'm in the design phase of our home and have been trying to learn the best way to add a thermal mass around our woodstove. Our build is a two story home. I was thinking of building a simple square chimney around the stove pipe all the way up through the roof.

My questions are:

1. What is the best brick?
2. How much space should there be between the brick and the chimney pipe (6")?
3. Can the brick touch the pipe?
4. Does the outside of the chimney bricks require any air gaps or can they touch framing / sheetrock / etc.
5. Is there a height where the bricks no longer serve a purpose. We have 10' ceilings, so by time this gets through the roof, it's over 25' tall.
6. Does this simple design even work?

I've attached two screenshots to show what we are planning. The first is a basic idea of what I was thinking to add mass. The second is the layout of how the stove will be placed near our foyer.

Hi Justin;
Clay bricks are best for your project.
Surrounding your stove with brick will certainly hold some heat for you.
However, you must maintain clearance between the stove and your bricks or it will overheat and warp.

If I understand correctly you are thinking of boxing in your stove pipe?
Creating a non-functioning chimney around your pipe?
I have not heard of this being done before, but it would certainly look nicer than steel pipe.
Even though I do not think the bricks would be hot enough to be a fire hazard, I would leave an air gap between any wood or sheetrock.

Is your intention for this faux chimney to be a heat-holding mass or is it more of a visual improvement?
My only concern is where and how you end this brick chimney.
How would you seal it off at the top end?
Ideally, it would penetrate the roof with the pipe and end outdoors.

Thanks for the info.

The idea of the faux chimney is for a heat mass. The visual enhancement is a bonus if I can pull it off properly on the second floor with our design.

As for sealing off the chimney, that was one reason I was curious if the brick could touch the pipe. I was thinking of taking the brick through the roof with the pipe and then closing it off against the pipe, and letting the pipe run a little longer past the chimney with a standard cap.

As for the clearance around the stove, what is a good safe clearance but close enough to heat the bricks effectively?

Hi Justin;
I would leave just enough room between the bricks and the pipe to allow the pipe to be removed many years later if needed.
I would also be sure to screw each section of pipe together so they can be removed easily if needed.
Clearance around the stove itself would vary between styles.  A stove with firebrick inside might be as close as 6", and a steel box stove might need a foot.
You can always dry stack extra brick closer if you need/ want more heat in your mass.
Ceiling fans and non-electric stove top fans will keep that heat spread out.
I would leave a 1-inch clearance around the faux chimney and use metal flashing for looks and to seal when you go through the roof.
Better safe than sorry when it comes to heat transfer.

Dig.

Not sure I’d cover up the stove pipe. You may need to get at it in the future. I have a corner installed wood stove and I stacked a good 1800 lbs of concrete pavers behind around and underneath the stove. It really helps even out the heat spikes and are still warm in the morning.