DIY wood insert... in a decommissioned fireplace

[koesdibyo]

We have been in the house for 1 year, and it has 1 functioning wood stove insert (main floor), and 1 pellet stove insert (basement)

We moved in the dead of winter last year, and scrambled with finding seasoned wood... so the winter was horrible.

It’s a 5 level side split, and over the course of the last year with all the COVID crap, we haven’t been able to get anyone in that’s been reliable and shown up, or hasn’t given an astronomical quote/wait time.

We were leaning towards gas because of the miserable year from our first venture - but already this year with some proper seasoned wood and some more knowledge on the units, I’m happy with wood... and as mentioned, most people coming by have quoted extremely high/long wait times.

There’s a ton of used wood inserts and pellet inserts locally, or I can even order something Iike a Drolet from Amazon.

Here’s where I come for help, as there are some issues with this just being a straight forward install.
- the fireplace was decommissioned at some point in its life... they took the chimney stack down from above the roofline. The roof was patched and re-shingled, and the flue ends in the attic.
- the firebox itself is a metal shell, and the damper is extensively rusted.
- the dimensions within the throat seem to be to narrow for a 6” flexible liner due to the damper.

As mentioned, the house is a 5 level side split. This fireplace is for the 2nd ‘main’ floor. My in-laws live with us, and I’d like to make this a duplex, so a barrier will eventually exist between my wood insert fireplace, and their ‘home’... so I need to get some heat on their side outside the single pellet stove in the basement that doesn’t do well at heating the floor above it.

I’d like to DIY as much as possible for a multitude of reasons;
- learning experience
- contractors tend to be booked solid and into the future
- cost savings; especially so since I’ve been terminated from my job as a first responder thanks to the current political climate surrounding mandatory vaccinations.

I will get it WETT checked before operating, and I am handy... just not well versed in fireplaces.

My intent:
- Flexible liner from the attic down to the unit
- Attic insulation shield would have to be a built blocker due to such close proximity to the eaves and not enough height for a store bought.
- Roof is 12/4 and as per the 10-3-2 rule I will need 64” of chimney above the roofline.
- Insulated chimney pipe is what I’d like to use, and leave it exposed and supported vs building a new stack

My questions:
- can someone ID the type of firebox I have... and can I get my grinder/sawzall into the throat and start chopping away at the rusted out damper to give clearance for piping?
- I know this is the WOOD forum, but as I understand pellet inserts typically are smaller in piping, so I could probably snake a 4” pipe through the 5” opening between the throat/damper... but would that be advisable *IF* I can’t go the wood route.
- any other things I’m missing or should be doing/know before moving forward?

Other notes:
Firebox opening sizes are;
34W x 22.5H x 20D at the face

The taper at the back of the box make it so at 22.5”H it is only 16” deep, and tapers to the 14”H mark to gain the full 20” depth.

Here are a few pics to help describe the situation better than my words can tell.


From the attic, looking to where the flue comes up, and now ends in the eaves

Again, from the attic looking into the flue

Last one from the attic, looking down the flue for any issues.



Looking up from the fireplace into the flue

Debris that fell down from the attic and now sitting on the smoke shelf

Some rusting on the damper.

Looking up from the firebox, showing how narrow it is (measured 5”)

I had stuffed it with insulation through last winter to help prevent a draft.

Here is the firebox up close.

 

[begreen]

There are no pictures of the fireplace, but by description it may be a heatform style metal fireplace. An insert can be installed if this is the case. The damper can be removed to enhance liner clearance. There are a couple of recent threads that show how some have done this.

Cut out heatform myself?

So I talked to local blaze king dealer and it sounds like they’re comfortable cutting the smoke shelf out of my heatform to allow for a rigid insulated liner and fitting an ashford 25 ( mind you this is over the phone so far) They said they would discount the install if I did the cutting...

www.hearth.com

There is a transition cap that bolts on the top of the chimney stub, to convert it to class A for up thru the roof.

 

[koesdibyo]

There are no pictures of the fireplace, but by description it may be a heatform style metal fireplace. An insert can be installed if this is the case. The damper can be removed to enhance liner clearance. There are a couple of recent threads that show how some have done this.

Cut out heatform myself?

So I talked to local blaze king dealer and it sounds like they’re comfortable cutting the smoke shelf out of my heatform to allow for a rigid insulated liner and fitting an ashford 25 ( mind you this is over the phone so far) They said they would discount the install if I did the cutting...

www.hearth.com

There is a transition cap that bolts on the top of the chimney stub, to convert it to class A for up thru the roof.

Damn, knew I forgot something.
Edited the post to add the firebox/fireplace pictures.

Thanks for the reply!

 

[bholler]

Damn, knew I forgot something.
Edited the post to add the firebox/fireplace pictures.

Thanks for the reply!

You will probably either need to remove the clay liners or run an oval liner to allow for insulation on the liner

 

[koesdibyo]

I will have to get back up in the attic and measure the ID.
Picture from top looks like a square, but if I recall from last time I measured its 8x12.

The chimney is exterior, and I’d definitely prefer to leave the tiles in tact if at possible.

I did consider a non-insulated liner, but all reading for safety and efficiency leads to insulated.

Drolet says 5” or 5.5” is fine for install, so that is also another option if I can’t find an insulated oval liner.

 

[begreen]

It's probably 7x11 ID. An insulated oval liner is possible, but I am puzzling out what happens at the transition to round class A pipe. Duraliner's transition anchor plate (9440A) terminates in round.

 

[koesdibyo]

I’m coming up within similar results oval to round adapters.

It might be a safer bet to go down to 5 or 5.5” as it seems to be more ‘normal’ in nature.

I’m not 100% on the Drolet unit - but being that they’re saying it’s safe, I can imagine similar units will be as well.

My current unit is a Heritage Renaissance, and it works... but it’s not the greatest unit for heating my component of the house (approx 800 sq ft main floor, and approx 800 saw ft upstairs bedrooms/bathrooms)

It’s not an insulated lined, so that may be a project for next year on this side of the house - but we’re having a warm spell currently, so if I can wrap up some roofing before the snow flies I’d be very happy.

 

[bholler]

I’m coming up within similar results oval to round adapters.

It might be a safer bet to go down to 5 or 5.5” as it seems to be more ‘normal’ in nature.

I’m not 100% on the Drolet unit - but being that they’re saying it’s safe, I can imagine similar units will be as well.

My current unit is a Heritage Renaissance, and it works... but it’s not the greatest unit for heating my component of the house (approx 800 sq ft main floor, and approx 800 saw ft upstairs bedrooms/bathrooms)

It’s not an insulated lined, so that may be a project for next year on this side of the house - but we’re having a warm spell currently, so if I can wrap up some roofing before the snow flies I’d be very happy.

There are some that allow you to run on 5.5" but very few allow 5". Oval is very normal for inserts. The only complication is the transition. They may have an adapter for it I don't know

 

[koesdibyo]

A few more questions and thoughts through the day...

As mentioned in the OP, there is a pellet stove insert in the basement area - which is a partial living quarters for my in-laws.

Of the 5 level side split, here is my breakdown;
- Bottom basement; storage (potentially looking at adding in a small studio apartment one day, but thats a future project.
No heat source initially, but I added a Senville heat pump last year, and ran a head to the basement to help with humidity

- Second basement; in-laws living quarters (living room/bar)
Heat source is the pellet stove insert (Harmon Iron).

- Main level; in laws living quarters (kitchen, dining, bedroom, bathroom)
Heat source is nothing. This is the room that has the empty/decommissioned fireplace

- ‘Main’ level #2; my living quarters (kitchen, dining, living room)
Heat source is the wood stove insert.

- Top floor; my living quarters (4 bedrooms, 1 bathroom)
Heat source is the aforementioned heat pump that I added a couple heads up here since we had that terrible first winter.

There is baseboard heat throughout the home, but it is extremely expensive to operate and won’t touch that with a 10 foot pole.

I’ve never actually examined the pellet stove. We had it wett checked, and it passed... and my knowledge of fireplaces was nothing at that point; ie. didn’t know the difference in language between an insert, stove, fireplace, etc.

Today, I pulled it out, out of curiosity to see if the flues could fit a 6” insulated liner, and see about upgrading it to a wood stove insert, and bringing the pellet stove to the main floor to make snaking a 4” liner up the flue in the OP (8x12 tiles).
It is a HUGE masonry fireplace behind the pellet stove insert.
42” W x 32” H x 40” D.

Plenty of room in the flue to fit a 6” flex liner down... hurray! Plus it’s already got the stack built, so I expect it wouldn’t take much to get operational with a wood stove insert.

Downside... the dimensions of the pellet stove are just a hair too small to fit into the fireplace on the main floor. If I could remove a course of bricks above the lintel, I’d be fine... but oh well, there’s a few pellet stove inserts in my area (used) that do have the dimensions to fit.

so here is where I have some (more) questions
- I had called around to find pricing on oval and 5.5” insulated liners... and at the same time inquired with a few chimney sweeps about install/breaking of tile.
I got a couple answers back saying they don’t deal with installing insulated liners. One said it was due to he didn’t feel they were necessary as far as he was concerned.

- Are non-insulated liners still advisable?
In either of my chimneys, they are exterior walled.
The 2 that share a stack are within the garage.

So I’m still awaiting pricing on a 5.5” insulated liner, oval insulated liners, and adapters for said liners to a 6” stove...

With all that being said; what are the options if I opt to carry on with the thought of pellet stove insert on the main floor up the narrow flue tiled chimney?

With the firebox being metal, could I cut a hole in it and do a horizontal exit straight back?
Or
*Could I exit out the back part way up the chimney? (Ie. drill through a tile, or break the top tile(s) and go from vertical to horizontal below the eave?

*im not sure how I’d make the connection within the flue, so this might be more or less a stupid idea...
My end goal is to prevent having to break through the roof line if I can.

With my roof pitch (4/12), and close to the eaves, I need 64” of exposed chimney pipe (using 4” if I go to a pellet)... which might look awkward and also be not great for security with such a small diameter to height ratio?

Below are some more pics of everything I thought might add relevance to better describe than my words.

 

[koesdibyo]

Stack from my main floor wood stove insert (left), and from the basement pellet stove insert (right)

Roof pitch for where the chimney I need to add (if doing vertical vent) will be. It will be at the edge of the roof.

Exterior of the ‘decommissioned’ fireplace.
*is it possible/ advisable to drill through the parging, cinder block, and of course the metal firebox to make a horizontal vent exit?

Exterior to show the stack removed from the decommissioned fireplace and it’s relation to where on the roof line it would go.

Basement pellet stove. The area behind this is massive, and I’d have no issues fitting a wood stove insert in.

One more of the exterior chimney from the decommissioned fireplace