what all would be involved in getting a big freestanding woodstove into this fireplace?

[Poindexter]

If i were to do that i would extend the liner off the bottom of the tee into the fireplace with a cap on the bottom then you could clean from the bottom easily.

Brilliant!!

 

[twd000]

If heat will convect to the upstairs from the basement then maybe consider an insert for the upstairs. That will provide a nice fireview and decent heat for milder weather or times when you don't need the basement stove/insert burning.

well currently the heat doesn't really convect upstairs from the basement. I have another thread here discussing my attempts to improve that situation. https://www.hearth.com/talk/threads/dampening-temperature-swings-and-distributing-heat.151712/
I'm going to connect the blower and try to move some heat upstairs, but I don't think this is going to be a viable arrangement for the majority of my space heating needs.

So I'm looking at these existing fireplaces, and yes they have that classic New England Colonial look. The chimney sweep remarked that that it was a $20k chimney. I don't want to mangle them or making something ugly looking to replace them. The problem is that open fireplaces don't produce heat.

Regarding an insert in either fireplace, I understand the theory is that the heat going into the chimney will eventually move into the living space. But the reality is that most of that heat is lost. The chimney is a massive structure, a tower of cinder blocks, a 4'x6' footprint extending from the ground/foundation, through three floors of living space, through the attic, and up onto the roof. It's gotta be over 40' tall. Several thousand pounds of cinder blocks that conduct heat to the cold ground and sky. It is covered by drywall through most of the living space.

So that's why I'm primarily interested in freestanding stoves. If the fallback plan was an insert for occasional weekend fireview, I would have a hard time justifying the investment of $5k for that without knocking down my heating bills.

Regarding the freestanding stoves, I have read a lot of positive reviews on both the Hearthstone and Woodstock stoves. My concern is the burn time/ burn cycle temperature profile. Its sounds like 8-10 hours is about what you're be looking at with those. Hence my interest in the Blaze King stoves, which advertise (and achieve) 12-24 hour burn times. At this time, my wife stays home and I can train her to operate the stove, but our younger son is headed to school next year and she will be back to work in some capacity. I know myself, and I know restarting a cold stove with kindling and a 30-minute catalyst activation, 2x a day...ain't gonna happen. Reloading a 4 cubic foot firebox on a bed of coals, every day when I get home from work..sounds like a good ritual.

So most stoves are too tall for my lintel. But why are they designed that way? Just for aesthetics,? Don't want a huge box sitting on the floor, and bending over to load it. The inserts sit directly on a non-combustible floor, which is what I would build out with my hearth.

I've been searching for someone who has done a thimble-above-fireplace install, and I'm coming up empty.. The other thing I could consider is removing a couple bricks of the lintel; I may be able to get 6" of clearance below the smoke shelf...

 

[bholler]

I've been searching for someone who has done a thimble-above-fireplace install, and I'm coming up empty.. The other thing I could consider is removing a couple bricks of the lintel; I may be able to get 6" of clearance below the smoke shelf...

I have done 30 or so. It is pretty straight forward and it is reversible you basically just punch a hole through into the smoke chamber. The hardest part is hooking the liner up in there. Modifying the lintel is much more complicated and much more destructive to the fireplace.

Regarding an insert in either fireplace, I understand the theory is that the heat going into the chimney will eventually move into the living space. But the reality is that most of that heat is lost. The chimney is a massive structure, a tower of cinder blocks, a 4'x6' footprint extending from the ground/foundation, through three floors of living space, through the attic, and up onto the roof. It's gotta be over 40' tall. Several thousand pounds of cinder blocks that conduct heat to the cold ground and sky. It is covered by drywall through most of the living space.

So that's why I'm primarily interested in freestanding stoves. If the fallback plan was an insert for occasional weekend fireview, I would have a hard time justifying the investment of $5k for that without knocking down my heating bills.

If you don't like the idea of an insert that is up to you and i am not trying to change your mind but honestly inserts get a bad wrap because most are not installed very well. We have many customers who use inserts very successfully to heat their home.

So most stoves are too tall for my lintel. But why are they designed that way? Just for aesthetics,? Don't want a huge box sitting on the floor, and bending over to load it. The inserts sit directly on a non-combustible floor, which is what I would build out with my hearth.

How do you plan to build a truly non combustible hearth extension? To do that you need to remove the framing then pour and support a slab in it's place.
.

 

[twd000]

I have done 30 or so. It is pretty straight forward and it is reversible you basically just punch a hole through into the smoke chamber. The hardest part is hooking the liner up in there. Modifying the lintel is much more complicated and much more destructive to the fireplace.
.

Do you have any photos? Do you punch out the bricks with a demolition hammer, or a cut them out with a concrete saw? Is the smoke chamber above the damper, but below my mantle? Or above my mantle?

How do you plan to build a truly non combustible hearth extension? To do that you need to remove the framing then pour and support a slab in it's place.
.

I thought I could remove the wood flooring and replace it with half bricks or a granite countertop section. How thick dos it have to be to meet code?

 

[bholler]

Do you have any photos? Do you punch out the bricks with a demolition hammer, or a cut them out with a concrete saw? Is the smoke chamber above the damper, but below my mantle? Or above my mantle?

We typically will use a combination of our arbor tech and a demo hammer and yes the smoke chamber is above the damper It may go above or below the mantle that depends on the situation. I would have to look at your to know.

I thought I could remove the wood flooring and replace it with half bricks or a granite countertop section. How thick dos it have to be to meet code?

Well that depends on the stove. To be clear most stove do not require this but you said about making the extension like the fireplace floor and putting a stove directly on it without legs. In order to do that you would have to have a truly non combustible floor structure meaning no combustible materials In contact with the bottom of that extension at all. Most stoves have specific requirements varying from simple ember protection with no real insulating value going up to pretty high R value requirements.

 

[bholler]

Here is the code for fireplaces which would apply if you set a stove on the floor without legs at all

Hearth extensions
R1003.9 Hearth and hearth extension. Masonry fireplace hearths and hearth extensions shall be constructed of concrete or masonry, supported by noncombustible materials, and reinforced to carry their own weight and all imposed loads. No combustible material shall remain against the underside of hearths and hearth extensions after construction.

R1003.9.1 Hearth thickness. The minimum thickness of fireplace hearths shall be 4 inches (102 mm).

R1003.9.2 Hearth extension thickness. The minimum thickness of hearth extensions shall be 2 inches (51 mm).

Exception: When the bottom of the firebox opening is raised at least 8 inches (203 mm) above the top of the hearth extension, a hearth extension of not less than 3/8 -inch-thick (9.5 mm) brick, concrete, stone, tile or other approved noncombustible material is permitted.

 

[twd000]

Thanks for the research. I'm not really interested in placing a stove on the floor without legs, but trying to understand why it is legal for inserts to do so.
A strict interpretation of that would lead me to believe this can only be achieved in a slab-on-grade house. In my three-story colonial, the sub-flooring and joists supporting the heart/hearth extension are certainly combustible. That's just not realistic. They're saying the entire hearth extension must cantilever out from the chimney, so it is not supported by wooden floor joists? Or can I build a 2" thick masonry extension on top of the subfloor?

 

[bholler]

They're saying the entire hearth extension must cantilever out from the chimney, so it is not supported by wooden floor joists?

Yes to be a true hearth extension for a fireplace that is what is required. But for a stove you only need to meet the r requirement of that said stove. It is very achievable for houses like yours but it is allot of work.

I'm not really interested in placing a stove on the floor without legs, but trying to understand why it is legal for inserts to do so.

Because they are on a fireplace floor which is truly non combustible not on a combustible floor covered with non combustibles.

 

[bholler]

In my three-story colonial, the sub-flooring and joists supporting the heart/hearth extension are certainly combustible.

If that is the case then your fireplace does not meet code. We actually had a customer of ours last month that we told his hearth extension was an issue have a fire under that hearth extension. His was 4" thick sitting on plywood and the floor joists. Enough heat transferred through to cause a fire.

 

[twd000]

If that is the case then your fireplace does not meet code. We actually had a customer of ours last month that we told his hearth extension was an issue have a fire under that hearth extension. His was 4" thick sitting on plywood and the floor joists. Enough heat transferred through to cause a fire.

wow, scary! Now was that from a freestanding stove with 8" legs, or another setup?

 

[bholler]

wow, scary! Now was that from a freestanding stove with 8" legs, or another setup?

An open fireplace. But the same thing can happen with a wood stove that does not have the required floor protection under it