Planning stages - replacing a ZC fireplace.

[qyota]

While the old Security Chimneys BIS is doing fine, my ultimate goal is to install a free-standing woodstove that will give us more heat and less worry. We didn't build this house, so I've been discovering things about it over the past 6 months we've lived here. The plan is to be here another 9-10 years, so I'd love to get this new stove installed next year, if possible.

I thought the chimney was masonry (clay-lined) all the way up, but I think that's not true now. You can see in the photos that there is a 9" (7" inner diameter) chimney coming out the top of the fireplace. I assumed it switched to a clay flue after going through the concrete "cap" at the top of the brick "box". However, now I realize it's probably insulated almost all the way up. The top of the chimney has a 7" square clay opening, surrounded by a mortar dome. Actually, there are two clay openings, but one is mortared closed. When I look down the top of the chimney, I see about 2 feet down that the flue changes to something round. I assume that is the top of the insulated steel chimney.

So here's the question. I want to rip out the ZC fireplace completely, which will leave me with an alcove situation, I believe. The current fireplace is elevated on a block-supported hearth, but the chimney "box" goes all the way down to basement floor level (overall height of chimney box is a bit over 8 feet, I figure). I assume that when I pull the BIS out, the metal chimney isn't just going to fall down...but I guess it might. I also assume that would leave me with an "open" masonry chimney within which I could run a new liner. I'd probably have to re-do the chimney cap to replace the mortar dome with a steel box and cap, supporting the new liner.

Does anyone have experience with upgrading this sort of installation? What else will I need to consider (aside from which stove to buy). I plan to completely re-do the hearth and pull the stone facade off the wall. I'd then build a new rock/stone-veneered alcove opening the entire height of the basement wall.

Exterior chimney and wood box

• qyota
• Dec 2, 2016

Security Chimney up

• qyota
• Dec 2, 2016

Top of BIS with Security chimney

• qyota
• Dec 2, 2016

Interior BIS

• qyota
• Dec 2, 2016

 

[qyota]

I assume also that there is no way I can keep the existing 9"/7" chimney pipe...even if it is ASHT? Looks like there would be room to support it from the underside of the concrete cap. I wonder if there is an adapter out there to get me from this pipe to a standard double-wall 6" smoke pipe.

I found the following support online, for example:
(broken link removed to http://www.woodstovepro.com/store/Chimney-Pipe-Venting-Pipe/Wood-All-Fuel-Piping/7-inch/Security-Chimneys-Secure-Temp-ASHT-7/Security-Chimneys-7-Secure-Temp-ASHT-Floor-Support-7SD-p29252.html)

I think this could be framed in under that concrete cap in the wood box to support the chimney in place of the fireplace itself. If I come off that end piece of pipe with a T, and adapt to 6" black pipe, I think I'll be in business. Something like this:

 

[qyota]

Follow up question. If I AM able to salvage the existing class A pipe (7" ASHT Security Chimney), would I be able to use a modern wood burner? I know most use 6" outlets, but I'm not sure what that means in terms of chimney diameter.

 

[begreen]

7" pipe would be ok to use for a 6" flue stove. Strong support for the chimney pipe is the issue. I'm wondering if that plate could be anchored directly to the concrete with tap cons or rawl anchors. A tee support bracket off the cement block wall might also work.

 

[qyota]

I like what you're thinking! I found a cheap source for the tee and a support bracket, I might just pick 'em up in the event I am able to use the existing insulated steel chimney. I won't get the vertical alcove I was envisioning, but just having the wood stove mostly "in" the room will be a huge improvement.

 

[qyota]

OK - here's where I am with this process.

Once I have the ZC fireplace pulled out, there will be about 20" length of 7"/9" HT pipe with a female end coming down into the block/brick box, which is outside of the house envelope. Connected to the end of that pipe would be an insulated T (already procured!), which will be mounted on an offset support made for this pipe (also procured!). To provide a mount for the support, I may need to build a steel support "cradle", or frame in a cross-brace from one side of the block box to the other, and attach the support bracket to that. THAT would take care of supporting the chimney.

Next task, come off from the insulated T to double-wall pipe through the house wall (thimble procured!). Then, elbow down to the top of the new free-standing stove. I have a 7"-6" double-wall reducer ready to go, so standard 6" double-wall from the stove adapter to this reducer/increaser should work.

This keeps the existing block box completely separate from the interior space, with only the pipe going through the thimble in the wall. No alcove requirements, as the stove would be sitting completely within the room space (8' foot ceiling). The floor is concrete, so I shouldn't need to worry about R-value, just normal distance to combustibles.

What am I forgetting?

Geez, I'm almost to the point where I ask "which stove should I buy?" !!

 

[qyota]

Current hearth setup:



This will all be removed when the ZC fireplace comes out. The wall will be repaired and filled in, with just the thimble going through. The door on the left I will keep, as it allows me to access the wood box.

 

[qyota]

Reviving this thread a bit. Here is my latest question:

Depending on the height of the stove, I'll need to turn the double-wall connector pipe back toward the thimble at about 5 feet height from the floor. This is due to the placement of the insulated T that will connect to the bottom of the existing chimney pipe. My question is, when selecting a new stove, are there stoves I should be avoiding because of this short vertical run, followed by two 90-degree turns? The chimney is about 20' tall and straight the rest of the way out. I will upload a drawing attachment ASAP.

I have not decided between cat and non-cat, or a hybrid, or anything else. I'm leaning toward the 30NC or the Drolet HT2000, but I also really like the Woodstock Absolute Steel and the Ideal Steel. I'm in northern Minnesota, so I don't have great local options like PE or BK, etc.

Thanks for your help!

 

[begreen]

Would it be possible to soften the first 90º turn by placing a 45 at the stove then go diagonally to a second 45 at the tee? That would help.
FYI, both stoves you've mentioned are good, or you can order a PE online from here: www.chimneysweeponline.com

 

[qyota]

Hi there. My attachment didn't work, so I uploaded the image of my drawing. See above.

Yes, it should be possible. The only downside is that the stove would have to sit farther out from the wall. Not a deal breaker, but if it helps with the draft, I'll do it. The horizontal run will be about 18", I figure. The T has a very short snout, but then I need a 12" piece of insulated chimney through the thimble, then an adapter from 7" insulated down to 6" double-wall connector. I could come right off that adapter to a 45, then maybe a 2-foot run of straight, followed by the 45 at the collar. That would put the stove about 2 feet from the wall, at least.

 

[begreen]

There are offset tables for double-wall stove pipe that will help you determine offset created by various length connectors between the elbows. Even a short 6" connector will help. In that case there would be a short riser off the stove before the lower elbow.

 

[qyota]

OK, I think we've decided on the Ideal Steel. The plan is to have one shipped here in the early summer, and have most of the summer to get it setup on a new hearth. I'll start a new thread when hearth demolition begins!

 

[qyota]

Demo has begun!

 

[qyota]

Getting there!

 

[qyota]

More progress today. Change of plans, I think. Instead of rebuilding the wall and running a thimble through, I think it would be nice to finish the chimney alcove and just run two 45s from the stove to the straight end of the chimney. No tee, thimble, or trim pieces needed! I think it would be visually more interesting too. Would have to insulate that alcove and finish it with stone.

New Ideal Steel will be here in 2-3 weeks!

 

[begreen]

Not quite as convenient for cleaning. How will the chimney be supported?

 

[qyota]

Roof is an easy slope, so top cleaning is pretty easy.

The chimney will be supported by this part fastened to the underside of the concrete slab the pipe passes through, with Tapcons:
(broken link removed to http://www.woodstovepro.com/store/Security-Chimneys-7-Secure-Temp-ASHT-Floor-Support-7SD-p29252.html)

I also plan to build a steel stand that will support the chimney from the floor below, using this part:
(broken link removed to http://www.woodstovepro.com/store/Chimney-Pipe-Venting-Pipe/Wood-All-Fuel-Piping/7-inch/Security-Chimneys-Secure-Temp-ASHT-7/Security-Chimneys-7-Secure-Temp-ASHT-Anchor-Plate-7SP-p29253.html)

The upper support will hold the chimney while the old BIS is removed. The lower support will just be bonus. That's the current plan, anyway. I'll have a better idea whether it will work once the BIS is out.

 

[qyota]

The BIS is out! Chimney temporarily supported, but will be permanently supported soon. New Ideal Steel should be here in a week or so, but lots to do with the chimney alcove and hearth. Will probably replace the tile with something new that compliments the colors of the new stove.

 

[qyota]

Chimney support is done.

 

[qyota]

The Ideal Steel is 5 feet from its final destination in the basement. Here's a shot of it rigged up on the trailer, ready to move. Stripped down, we moved it on a regular appliance hand truck without too much drama. The old BIS was a cakewalk to bring back up the stairs, in comparison.

Work continues on the hearth and wall. I'm chipping up the tile thinset, and we'll put down new tile before moving the stove into place.

 

[HisTreeNut]

Looks good so far to me...there's a reason I cook for a living. Cache easier to see the finished set-up...

 

[qyota]

Current status:

 

[qyota]

Slow progress.