Refurbish an old Chimney. Diy or Not?

[Ohlen Corbett]

Thanks for taking the time to read this. I know I get long winded, but I want your opinion and you can’t give me an honest one without all the facts.

We currently use LP as our main source of heat, and the price has skyrocketed in recent years. I live on a farm, and we have plenty of fence rows with green lumber, not to mention, wild woods. Seems logical to grow my own heat, rather than pay for some dead dinosaurs.

I’m thinking of resurrecting an old chimney in a ca. 1920 farmhouse. The top of the chimney was taken down recently when a metal roof was installed. Most of the mortar (what looks like sandy clay) had washed out, anyway. The mortar still looks solid on the parts that were inside the roof. It is a double fireplace, the East smoke chamber opening was sealed up, when a set of vent free gas logs were installed. I want to use the West facing fireplace to install an insert to be the main heat in the house. The fireplace opening is 28” High, 33” Wide, and 16” Deep. The hearth is 16” deep, 48” Wide, and 1” above the linoleum. The flue is 12” square. The firebox sidewalls appear to be 8” thick, while the flue walls are 4”. The whole chimney and hearth is sitting on a pillar of dirt built up from the ground.

For the longest time I thought the whole chimney was a write off, but then I stumbled across UL 103-HT metal chimneys and insulated stainless flue liner. I now wonder if it could be made safe to operate.

My first idea was to remove the flue bricks (unlined chimney) and attach the metal chimney to the smoke chamber, then use an insulated flexible liner to attach to an insert. Then I found that at Rockford, Class A HT chimney, at $3.58/in., is more expensive than SS 316 insulated liner, at $2.56/in.

My next idea, then, was to use an insulated, smooth wall, flexible liner up to the top of the existing chimney, then finish with Class A HT chimney. I was looking for metal prices at Lowes to make a block off plate, when I saw that they had their SuperVent chimney parts on clearance for $65/36”, or $1.81/in. This stuff is made by Selkirk and, from what I can find, has the same warranty, and is made of the same materials, as their MetalBest line.

So now the plan is to use as much Class A as I can, and finishing up with a piece of insulated flexible lining.

If you've made it this far, could I now ask some questions? Other than these two?

Does this sound like a safe thing to do, or would you rather tear the whole thing down and rebuild to modern code?

I’m a handy man, and like to keep costs down by doing most work myself. (Also, I’m too cheap to pay for something I can do myself.) That said, is it safe for me to install this stuff myself? It looks easy to me, but looks are sometimes deceiving.

Barring the fire losing containment, how hot can I expect the outside of the chimney to get if the insert is used 24/7? Will most of the heat in a modern insert be directed out the front? My current favorite insert is 27” wide, which will leave a 3” air gap. The reason I ask, is that there are some wooden beams touching the masonry on the corners at the opening, and I don’t want to be unsafe. This is a loadbearing wall, so I don’t want to touch them. Anyway, I can’t access the one on the left without removing either the chimney or the wooden wall.

If this looks like it will pan out, I’ll post some more questions, but they’re moot if I can’t do this myself.

 

[mellow]

I vote for tearing it down and just running Class A in a wooden chase to hide where the chimney was. Install a free standing stove and you will be more happy if that is possible.

 

[elmoleaf]

+1 on mellow's recommendation. If you currently have wood bearing on the existing masonry chimney, it is not safe. I believe you would require a zero clearance insert, not an insert made for installation into a code compliant fireplace.
Perhaps you can remove the brick chimney and the non-structural firebox portions enough so that you can install the class a chimney and zero clearance fireplace?

 

[Oregon aloha]

First question I have: Do you like the current look of the fireplace? If so, my thought is at 28" high you could install a free standing stove in the fire box with the smoke shelf removed and a block off plate. I think this might fit the vintage and style of the home better. (It will provide better heat for your home.) You might need a hearth extension, but if the fire box was designed for direct heat from a fire, I would think it would be safe with a contained fire in the same space if the brick and mortar is not damaged and the chimney is lined.

When looking for a stove, find one that has the firebox EPA approved for insert and freestanding.

The wood contact with the masonry: Mine has the same wood brick contact on the corners of the opening. My brick mason wasn't concerned when I pointed it out to him, but he made it a point to tell me it wasn't up to code. He had more concerns about rot from the moisture in the brick then fire.

 

[Ohlen Corbett]

mellow:

This home was built by my great granduncle (not sure about how many greats) in 1923. I really want to keep as much original chimney as I can, while rendering it safe to use. I realize the several benefits freestanding stoves have over inserts, but there really isn't any other place to put it that is centrally located. Also, there is only 9' between the front of the fireplace and a kitchen counter. If I installed a hearth-pad and placed a stove in front of the chimney, you would be tripping over it all the time. Since you must navigate this passage to use the main entrance, I don't want to clutter it up. Not to mention the danger of falling on a hot stove.
​

elmoleaf:

I know that wood touching masonry in a fireplace is against code, and I understand why. The story told me, is that when this chimney was first built, they built it around a floor joist. Of course it caught fire pretty soon after the chimney was put in service. After they corrected this "minor" fault, nothing but creosote has ever inadvertently caught fire. If the wood were touching the back, or the smoke chamber, or some other high temperature area I would certainly either devise a means to move the beams, or replace the chimney. I posit that this fireplace was used as a primary heat source for 30 years as an open fireplace, then another 25 years with an old style slip in insert. I'm not saying that past experience is a predictor of future circumstances, but it does show a trend of not spontaneously combusting. I would think that a modern EPA insert would be much cooler on the sides than a metal box, but never having owned one, I wanted to make sure that my assumptions are correct. I do plan on filling any spaces around the insert with Roxul, unless this has been shown to speed the heat transfer through conduction rather than IR radiation and convection.

I have looked at some zero clearance fireplaces, and they don't appeal to me. Firstly, they are more expensive. The look is too modern on most of them. Also, they are difficult to change out. If I decide to change looks or brands, or if the replacement parts become unavailable, it is much easier to swap an insert in a masonry fireplace.
​

Oregon aloha:

I love the look of the fireplace. I've seen it all my life, and am not tired of it yet.

See my previous answer about a freestanding stove.

Thankfully I haven't noticed any rot around the chimney. When we were renovating the house, we had to replace several sections of ceiling where the roof had leaked and rotted out the boards, but the area around the chimney looked solid.​

 

[Oregon aloha]

My suggestion was to put the free standing stove in the same place you were installing the insert. That way you won't cover up your fireplace with the surround. You could also install a insert and not use the surround, but with 28" I feel the freestanding stove would look better.

 

[Ohlen Corbett]

I'm sorry I didn't understand your suggestion, Oregon aloha. I hadn't thought about putting a free standing stove into the fireplace. Do you have an example stove?

I'll think about it and research air movement options, but at first blush I would be concerned about the amount of heat radiated to the sides and back. Would an insert be better at blowing the heat into the room without needlessly heating the masonry? I know that there are heat powered fans that you can place on your freestanding stove. They would work in a power outage. I know that power outages are crippling to the efficiency of an insert. I need to do further research. Thanks for the input.

 

[Oregon aloha]

Are you planing to heat 24/7? If so once that thermal mass has obsoleted heat around the stove it will give it back to your home. Much like the soapstone stoves take longer to give off heat, but give out softer heat, so will the open masonry around your stove. Make sure you have a block off plate or other seal so you don't have heat loss up your chimney and you will enjoy the heat while preserving the look of your fireplace.
You will want a stove that has an EPA rating for both insert and freestanding,(example: Kuma Ashwood) because the stove will still be considered an insert with your insurance company.
Also the design of an insert has double walls that projects more of the heat out the front of the stove keeping the sides and back of the stove cooler.
There are examples in the photo section of the forum. I am almost done with my similar install and will post photos on completion. Hopefully this next weekend.
I hope this helps.

 

[mellow]

If you decide to keep the masonry fireplace but want a free standing a Rear Vent stove is what you will be looking for, it can sit in front of the fireplace and takes up a little less room than a free standing.

Not sure what your budget is but with a new rear vent free standing stove and class A pipe you will be well north of $5000 for materials. I would not trust running flex for this install.

(broken image removed)

 

[Ohlen Corbett]

I've thought about it and looked for stoves that could be used as inserts. I would love the look of a fancy cast iron stove inside the fireplace, or better yet, sitting on the hearth, so you can keep a water kettle on it. Alas, it doesn't seem to be an efficient use of my space. This house is about 1800 sq ft. with 10ft ceilings. We are trying to improve the insulation, but it will most likely always leak. I know we don't have really cold winters here in South Carolina, but there is usually a week or two a year where the temperatures dip into the teens at night. I'm thinking that we will need at least a 2.5 cu. ft. stove to replace most of the propane heaters scattered throughout the house. We may need a 3 cu. ft., but I am leery of getting the kitchen/dining area too hot. This fire chamber requirement means no pretty freestanding stove that I've found will fit in the opening without major modification. So unless someone knows of a good freestanding stove with a 2.5 cu. ft. firebox that only stands 28" high, and is less than $2000, I think I'm going to go with an insert. My current favorite is the Osburn 2000, or it's cousin the Enerzone Solution 2.3-I.

Now, about the safety. In looking at the user manual for the Osburn 2000, it looks like the stove is surrounded by an air sleeve and the blower intakes air from the bottom front, and the hot air comes out on the sides and top. Is this a correct assumption? If so, then the outside of the insert isn't going to be very hot at all, compared to the smoke dragon steel box insert of yore. In my mind, that makes it safe to use in my current fireplace, especially if I insulate the fireplace with Roxul before I install the insert. Does anyone disagree? Am I playing with fire, or taking a calculated risk?

Oregon aloha:

I thought about the chimney acting as a reservoir of heat, especially since this is an internal chimney. The area the chimney is in, however, is not insulated and is open to the roof. The heat on the outside of the chimney will simply convect upwards to the roof and, if not cooled already, leave by way of the ridge vents. The cool air will fall out of the attic and fill the closet that the chimney is in. Instead of loosing this heat, I would rather keep it in the insert and blow it into the room. I haven't had much luck finding something similar to your Ashwood. That stove isn't available locally, nor online. My search fu is also weak, since I can't find the others that you were referring to. Also, I only want to spend $2000 on a stove. The Osburn is already pushing that.
​

mellow:

My current plan is for 15' of Class A down to the top of the smoke chamber, then insulated flexible smooth-wall 316Ti liner from that to the stove. I wish I could go with Class A all the way into the insert. As this is a double chimney the flue is too far back for a straight shot.​

 

[mellow]

Another member is looking at getting the Buck 261, it would fit the bill for your install as well. He found it at a local dealer for I do believe $1800. I found a new one on ebay in KY for $1275:

(broken link removed to http://www.ebay.com/itm/BUCK-STOVE-MODEL-261-FREE-STANDING-OR-INSERT-WOOD-STOVE-/190921821937)

(broken link removed to http://www.buckstove.com/model-261.html#.UmkhlhDwpig)

 

[Dave A.]

it looks like the stove is surrounded by an air sleeve and the blower intakes air from the bottom front, and the hot air comes out on the sides and top. Is this a correct assumption?

Not familiar with the Osburn in particular, but all inserts I know intake cool air for the blower system from the bottom (or the sides) and exit the hot air on the top. If the Osburn is like the Century (and they are both SBI inserts) the side vents are not part of the blower system, though some hot air (not forced) will exit there from convection. (If I'm mistaken, hope someone will correct this.)

 

[Ohlen Corbett]

I was looking for information about the safe temperatures for long term wood exposure, since I know that I want to burn 24/7 and that wood doesn't have to catch fire in order to lose structural integrity. (for example, lump charcoal is quite brittle) I found this interesting article from the Ignition Handbook titled:

(broken link removed to http://www.doctorfire.com/low_temp_wood1.pdf)

From the article I glean that wood damage can occur at much lower temperatures than I thought, even lower than boiling water. I checked the 4x4 studs beside the chimney, looking for heat damage. All the raw wood in the house is a dark brown, and this didn't look any different. I tried to scrape the side beside the chimney, and it was hard as... well... old wood. I'm sure this fireplace, and it's former insert have been overfired at some point in it's life, so I'm feeling pretty good about the chimney safety in that respect. I still plan to check the temperatures on the outside of the chimney once I have a fire going, and frequently thereafter, until I know how the temperature varies on the outside. An excellent time to use my infrared camera. I'll even post some pictures to break up my series of long posts.

On to choosing the best* insert** and buying chimney parts!

* Best: Most efficient burns, longest lasting wear parts, cheapest to repair, longest warranty, best customer service, under $2000 USD, fits in my fireplace.
** Insert: A freestanding stove or insert that fits into my fireplace and doesn't require a hearth extension other than for ember protection at a distance of less than 12". Price should include the complete unit with blowers. I've been bouncing back and forth over whether to have a surround or not. At this point I don't think it matters. It is more important to me that the old chimney stays. I don't need to see it to know it's there.

Chimney questions to follow:

I currently plan to buy the chimney sections and whatever pieces they have on sale at Lowes. I haven't seen a rubber boot kit for metal roofs there. Are there generic kits available like the one Selkirk offers that include the 1" standoffs? Should I just buy it online? Will the boot kit for Metalbest UltraTemp work on the Supervent Pipes since it is universal? At $65 for a 36" section of chimney, is there a cheaper option with the same warranty for DIY installs?

The chimney install will have to be offset. What is the best way to transition from the Class A to the appliance? I wish I could come out of the stove with class A but without being able to access the inside of the chimney with the insert installed I think that is untenable. I was thinking smoothwall flexible SS insulated liner. I can't find any short sections available on the internet. Is there an online source? Where would one look for liner by the foot locally?

There will be lots of room around the liner as the throat and smoke shelf have been removed in the past. There is only a vertical wall that stops just above the level of the lintel. I will use the foil and mesh to achieve UL1777. Is it safe to then wrap the pipe with Roxul? Will this help or be a waste of money?

My flue is 12" square, and the flue adapter I see is a 9" square. How do I attach it to the inside of my chimney? How do I attach the liner to this plate? Can I drive two 1/4" steel bars between the bricks and let the anchor plate and chimney rest on them? With this setup do I have to buy the adapter plate at all, can I just use the stove pipe adapter?

Would it be better to buy the roof support?

So many questions! Is there any help for me? Do you need more information?

 

[Ohlen Corbett]

Well, I didn't mean to scare everyone off.
I keep learning more and more from these great forums.
I decided to try and show everyone my chimney situation. I will get pictures too, if they will be more helpful. I had to teach myself SketchUp today, so don't be too judgmental.

If this were your chimney, how would you install an insert?