Re-line a metal pre-fab chimney for wood stove? Please help!

[jwfrazier]

Hi,

This is a great site and I have been reading for days, but I can't find exact answers to my questions. It seems most everyone is installing wood stoves in masonry chimneys.

I have a 33' high, Class B 8" metal double wall chimney in a wood interior chase, for a zero clearance pre-fab metal fireplace in my home. Think the cheapest builder grade small fireplace you can get. I assume this chimney is not suitable for a wood stove, and I need class A 2100 degree chimney.

I want to install a wood stove that sits in the room such as a Jotul Oslo or similar.

Can I reline this metal chimney or do I have to rip it out and replace. A liner would be much cheaper it seems. Do I have to insulate the liner? It is a straight shot up the chimney.

Also my chimney cap is painted black metal and covers the entire chase, approx 3'x4'. Can I just take it off and properly cap the interior liner and than put it back? It vents out through slots in the side. Pretty standard.

I can take pictures of my system if needed. Thanks in advance for any help!

John Frazier

 

[kd460]

Hello John, your installation is somewhat similiar to mine. I have a builders basic prefab zero clearance fireplace made by Heatilator. It has a similiar cap to yours as well. However, I installed an insert in mine and not a free standing wood stove. So some differences in the install.

However, as far as the liner goes, the answer is yes. You can put an approved flex liner down your prefab double wall chimney. As far as insulation, I highly recommend it. I installed mine at first without it, then ended up removing the liner and then reinstalling it with the insulation. I was not sure if 1/2 inch insulation would fit, so I went with the 1/4 inch thick stuff. I feel the 1/2 inch would have fit, but like I said, I was not sure, and the mesh that covers the insulation does take up some space as well.

The fact that your chase is in the interior helps, and maybe 1/4 inch is all you need. Perhaps someone else will be able to tell you if 1/2" plus mesh will fit for sure.

I had the type of cap you described for the first season, but ended up changing it out for the next season. It built up kind of fast with creosote, so I had to clean it often. I went with a more conventional style the next season and am happy with it. I did have to buy a short 12 inch section of the original double wall pipe to bring it up above the chimney chase a little more. That is something to consider when you run the liner, as you will need to leave it longer to accomodate that added section (if needed). I think the cap I bought was just a standard item sold at Lowes.

As far as stove conections in the room, I can't help you there (mine is an insert), but, hopefully others will chime in.

A pic or two is always a good idea. Good luck. KD

 

[jwfrazier]

KD, Thanks for the reply.

If you do not insulate, could the sides of the liner touch the inside of the original double wall pipe and create a fire danger, or is the insulation just to help with creasote buildup? Some websites are selling double wall liners such as the following:

(broken link removed to http://www.chimneydepotsupply.com/2chliki.html)

Are these recommended and could you skip the insulation with these? I only ask bacause my chase is interior, and I wonder if the insulation will be hard to fit down the pipe. (and it is expensive)

One other question if anyone else is reading: At the bottom of the liner I assume I should attach a Class A stainless tee. Is an adaptor needed to attach to a double wall stove pipe? How is this connection made?

Again, I thank you all,

John F

 

[kd460]

I ran mine one season without the insulation without a problem. As far as the it touching, I don't believe it is a problem, but I can not say yes or no for sure. I believe I was told by members here a few years ago that this would be fine. However, I personally feel the insulation is worth it, and may even be required to maintain the warranty of your liner. Certian liner manufacturer's require it to be insulated, some don't.

I also notice my liner stays cleaner with the insulation, but it's a judgement call on your part. Hopefully you will find the information do be sure. I know the manual for my insert described my install using my type of double wall pipe and showing the liner type installation without the insulation.

THat double wall looks nice, and I never knew it existed. Looks like good stuff. BTW, check your PM for more information I sent you. KD

 

[minrack]

We had a wood stove installed in front of our fireplace and vented up a zero clearance fireplace. When shopping for a stove we could not get a straight answer from the wood stove dealers in our area as to the proper way to install or even if it would be possible. We went with a hearthstone homestead which is advertised to be able to be installed into a zero clearance fireplace. Our dealer called hearthstone to verify that this was possible and they said as long as clearances are maintained. This was still a little confusing since the stove back looks like it is shaped for an insert. We ended up extending our hearth out (which was another crazy project to get the appropriate fire rating underneath) to get proper rear and side clearances. The Homestead has the option to vent out the back which is what we do. There is a section of triple wall pipe that connects to a T and then new double wall pipe that lines the old stack with a new cap on it. We passed our inspections from the county mechanical and our insurance company.
We are happy with the way it worked out. The stove is a nice stove also. If I could figure out how to add pictures of this I would.