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New Member
Feb 1, 2023
Hello! I posted on here before about my situation with a Vermont Castings Winterwarm fireplace box surrounded by masonry that had a Blaze King installed in it by the previous owner. I finally took the time yesterday to do some demolition and reveal the underlying structure of the fireplace. As you can see in the photo, the structure of the fireplace is all masonry. It's basically a large masonry chimney that has a winterwarm cabinet in it and an opening for the fireplace. Between the winterwarm box and masonry there is about 10 inches or so of air space that also accommodates a couple of liners that travel up from the basement boiler and fireplace. The blaze king is currently connected to an 8 inch insulated SS flex liner made by Homesaver and the chimney is about 35' tall measured from the fireplace. I am selling the blaze king because I know it is supposed to be installed in a masonry fireplace. I'm looking for a safe and reliable solution that can also put out a lot of heat for winter. I have a couple ideas below, please let me know what you think and feel free to share any ideas that you can think of.

1. Treating the structure as a non-combustible alcove:
- This would involve cutting out the winterwarm box in pieces and installing a free-standing stove in its place because it clearly states on the side of the box that a fire can not be .
- The Lopi Liberty has clear specifications in the manual about installation in a non-combustible alcove. The current structure would exceed those requirements, however the chimney max height in the manual is 33' and the chimney size required is 6". Would this be a problem? Are there any other stoves that would work better for this purpose?

2. Installing a rear vent stove on the hearth right in front of the opening:
- The hearth is deep enough that I could install a free-standing stove in front of the opening and still exceed 16" in front of the stove.
- My biggest question with this idea is: Could I keep the winterwarm box, paint the inside black for aesthetic reasons, and have the chimney pass through it? Is this legal and could I run into any insurance issues with this approach?
- The stove that I am leaning towards for this would be the Vermont Castings Encore or Defiant because of the rear-vent capability and 8" chimney diameter.

What can I do with this?

Please let me know what you think!
Is there at least 8" masonry surrounding the current enclosure? Is the liner insulated? I hate to see you get rid of the BK without further advice. @bholler will know the code requirements.
The bk may be perfectly fine. We need a bit more info on the construction details of your "fireplace"
There is 9" of air space between the winterwarm box and the masonry and I measured the masonry to be 4 inches thick. The liner is also insulated. I feel like it would probably be safe to use because the box was originally designed to be surrounded by wood framing but I worry about insurance coverage if anything were to happen-- especially because there is a metal tag on the inside of the box that says "Do not built a fire inside this cabinet unless the Winterwarm 1280 is installed".
The side walls "look" to be 8" thick, but if not, remove the WW box and add 4" of masonry to make the walls 8" thick.
They need to be 10" thick if not using firebrick inside. 8 with firebrick
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I measured the sidewalls to be 4" thick. They take a 90 degree turn towards the fireplace which makes them look thicker. The problem is that there are 8" SS liners running up from the basement between the box and the masonry so I wouldn't be able to build the walls any thicker unfortunately.
In that case, the rear vent plan would work if the lintel is high enough, but I would consider a Jotul F55 or a Woodstock Ideal Steel instead.
Yeah that's the plan I was starting to lean towards. Would the venting be able to run through the Winterwarm box without removing it? Also would I have any issues with adapting the Jotul to the 8" liner that is 35' in length. The reason I was leaning towards the VC Defiant was because it is rear vented and designed for a 8" diameter chimney. I have heard that people have issues with VC stoves though.
I don't see a problem running with the box in place.
It's not ideal, the liner is oversized, but may work. The tall height is a concern. Was there any issue with the BK on this liner? If so, a key damper may be required to reduce draft.
There weren't any draft issues with the BK from what I could tell. It was easy to light a fire and it never ran away on me or anything. I also played around with the idea of installing a zero clearance unit like the Osburn Horizon (approved to connect to an 8" liner through a masonry chimney) in front of the chimney and building a chase around it but I'm not sure if it would be worth the expense and extra work of framing around it.
@bholler just wanted to check if you agree with begreen that it would be acceptable to do a rear vent stove and run the venting through the box and up the masonry chimney?

Thank you guys so much for your knowledge! I really appreciate the help.
@bholler just wanted to check if you agree with begreen that it would be acceptable to do a rear vent stove and run the venting through the box and up the masonry chimney?

Thank you guys so much for your knowledge! I really appreciate the help.
Yeah I don't see an issue with that