1920s chimney firebox removal for wood stove insert

[dendros]

Good afternoon,
We have a 100 year-old home with the original fireplace. In the 1980s, a previous owner had put a gas insert into the fireplace which has been removed. We are now looking to put a wood stove insert where the gas insert was, but are struggling with finding one that will fit in the existing firebox. (We need a new face in it too, which will be taken care of)
It appears the fire box at some past point came loose, and cracked on the sides (see the pictures below). Removing this old section of cracked mortar and brick will allow us to figure out how large of a box we can actually put into it. The plan is to remove the old firebox brick (back and sides) and install a wood insert fireplace.
What should I watch out for before I begin removing the section that is cracked on the left and right? Does the old firebox need to be replaced, or can it be just removed and a wood inseet be installed? There is no damper in place anymore, and a new liner will be installed. It has the cleanout at the back which will we are thinking will be left alone unless there is a reason it should be sealed up. I’m not sure what else I should be looking at. I appreciate your insights!

 

[begreen]

Note that there is a big difference between an insert and a zero-clearance fireplace. An insert goes into the existing masonry structure with an insulated, stainless steel liner installed in the chimney. One would not remove brick in that case. The opening looks pretty generous. If so, it could accomodate a large insert. An insert install could run anywhere from $4500-9000 depending on the model and liner length.

A zero-clearance (ZC) fireplace is sometimes mistakenly called an insert by marketing. If it were to go here, the entire fireplace, chimney and all, will need to be removed. Then a new enclosure (chase) would need to be built around the new ZC fireplace and chimney. A ZC install could run from $10-20k+.

 

[dendros]

We have been looking at inserts. (Thank you for the clarification). There is a local company who installs if we buy the unit. (So, I’m doing the homework)

Why would the old damaged brick not be removed? (I’m not saying remove all of the brick, just the brick that was the former fire box ) Doesn’t it have enough of an insulative value to keep the needed temps the same as a free standing stove?
Unfortunately, the opening isn’t as wide as it seems.

37-1/4 across the front
24” across the back (if my notes are right)
28-3/8” tall
depth 16-1/2”

It is deceptively shallow. we haven’t found one that we like to install on it yet which is why we are looking at moving the brick out. I’m not sure what was burned in it in the 20s.

 

[begreen]

Leave the brick if installing an insert which requires 10" of masonry surrounding it.

How would the insert be used, nights and weekends or 24/7 heating? How open is this room to the rest of the house and what is the square footage of the room and the house?

 

[dendros]

The intent is to use it intermittently during winter and in case the power goes out.
It opens into a 13’ x 30’ room on a 13’ wall. (roughly 388 sq ft.)

The house is about 1460 sq ft on the main floor,
180 sq ft on the second floor bedroom
and 500 sq ft in the basement rooms.

So, roughly 2140 ft.²

The pictures below indicate a closer look at firebox at the back, the cracks along the left and right side between the fire box and brick structure and a extended photo of the entire area.
If not removed, then shouldn’t they be repaired? Where can I find the requirements for the brick thickness around an insert? So far, my Google searches have shown nothing. is it buried in the NFPA?

 

[begreen]

Is the fireplace room open to the rest of the house, or closed off by a doorway?

It sounds like a medium sized insert in the 2 cu ft range would suffice. For power outages it should not be flush. Flush inserts need the blower running to convect heat. Is this fireplace on the main floor or basement floor?

 

[dendros]

It is closed off and at the opposite end of the house from the bedroom. As with the old homes, each room including the hall has doors. The house is lath and plaster throughout.

It is on the main floor.

If I recall the existing box will hold one smaller than that because of the internal dimensions.

Do you have a source for your standards uou would share? (i.e. 10” brick thickness)

 

[bholler]

It is closed off and at the opposite end of the house from the bedroom. As with the old homes, each room including the hall has doors. The house is lath and plaster throughout.

It is on the main floor.

If I recall the existing box will hold one smaller than that because of the internal dimensions.

Do you have a source for your standards uou would share? (i.e. 10” brick thickness)

Irc chapter 10. Its 10" with no firebrick 8" with firebrick

 

[begreen]

It sounds like the insert will heat the stove room mostly and not the bedrooms. Take a look at the Drolet Escape 1500 insert, or its more upscale equivalent, the Osburn 1700. The more expensive Lopi Evergreen might also just fit.

 

[dendros]

It sounds like the insert will heat the stove room mostly and not the bedrooms. Take a look at the Drolet Escape 1500 insert, or its more upscale equivalent, the Osburn 1700. The more expensive Lopi Evergreen might also just fit.

That was what we had come up to and I’m OK with that because I like bedrooms to be cool for sleeping..

I’ll take a look at those.

Looking at IRC 2018 it indicates the depths of the fireplace has to be 20 inches. The depth of our fireplace is under 17”.
How much of a problem is this? Any installation of an insert will not be the code without a rebuilding of the fireplace.

 

[bholler]

That was what we had come up to and I’m OK with that because I like bedrooms to be cool for sleeping..

I’ll take a look at those.

Looking at IRC 2018 it indicates the depths of the fireplace has to be 20 inches. The depth of our fireplace is under 17”.
How much of a problem is this? Any installation of an insert will not be the code without a rebuilding of the fireplace.

The size requirements are just silly and really mean nothing. I have never had any issues with inspections as long as clearances are met. If you can find an insert that fits it will be fine as long as you have the proper clearances

 

[begreen]

This ^^. There are a lot of fireplaces that are under 20" deep and still accept an insert.