Insulated Liner in Clay Flue for Woodburner (questions)

[Charles1981]

I think from reading the FAQ section most of my questions are answered but I still wanted to discuss my situation.

We are a week or two from closing on a foreclosure, Just awaiting results of the appraisal.

I have been researching wood stoves a lot recently. This house has an interior chimney structure. There is a 8x8in clay lined flue for the upstairs fireplace. There is a 12x16 clay flue for the downstairs fireplace. During inspections I had a mason inspect the chimney gave it the aok, but said there was

1) cracked mortar in the cap around the flues that someone had patched
2) No crown to allow for water to drip away from the chimney
3) Severe creosote buildup (reasons why will be discussed).
4) improperly installed flashing around the chimney (amateur) although the mason didn't think it was leaking he recommended it be re-done as did the house inspector.

4) he said the clay flue liners were very new and in good condition but the creosote was pretty terrible (especially in the larger flue)

So from the posted pictures you can see the fireplace for the 8x8 flue.

The problem is the 12x16 flue. The previous owners have a "window" into the brick structure for the downstairs chimney, with a stove pipe insert. This stove pipe elbows into the chimney and stops at the Damper Bars. Even the damper bars are line with creosote. I don't have exact measurements either but it seems like the stove insert pipe is only 3 feet or so off concrete slab (seems like it might be difficult to exhaust a stove with the "window" so low.

Question 1: Obviously the huge 12x16 flue with a 6inch pipe at the damper was likely the cause for the severe creosote buildup as it created a poor condition for drafting and perfect condition for creosote. Correct?

Question 2: The other side of "window" is where the original fireplace was with glass window. It isn't blocked off or anything. It would appear this is a fireplace, someone punched out a whole in the back end with the intention of converting it into a wood stove chimney. As we haven't purchased this and the Mason nor the Inspector were quite sure was code regulations would be about this setup (stove on one side, open chimney on the other). The inspector was prone to think the original chimney opening would need to be "blocked off" in some respect to prevent its use as a fireplace anymore. What are you opinions?

Question 3: It seems the best course of action due to the huge flue size of 12x16 that the damper bars need to be removed and either 6-8inch stove pipe run of the chimney? (There is no curve to the damper....it just goes straight up. What are you recommendations? Should it be 6 inch, 8 inch, flexible, rigid? Should I insulate even though the chimney is interior and not exterior?

Question 4: It is OK to run chimney liner up the clay flue? especially with the good condition of the clay liner? After getting the creosote cleaned.

Question 5: As long as it is ok to run a metal liner down the clay flue after thorough cleaning, give how large the flue is I kind of feel this could be a DIY job, however I want everything to be kosher as far as being code and my house insurance not having any problems with anything should something ever happen. It just seems like (and from watching videos) given how large the 12x16 flue is that it would be no problems getting even insulated 6-8inch pipe down there. My research is showing that at ! 25 feet from basement to top of chimney we could be looking at 2000-3000$ for a chimney sweep to install the liner, when it seems I can order a kit and parts for well under 1000$.

Question 6: The chimney is fairly central to the house (1050sq footage) and basically the entire house is electric (no gas, oil, propane) what recommendations on wood stoves do you all have?

Any other concerns you all have regarding this situation?

 

[KaptJaq]

Welcome to the fourms, good luck with the house.

I'm going to guess here but it looks like the downstairs fireplace may have originally been open to both rooms. Was it punched out or properly finished by the original mason? Probably sucked a ton of hot air out of the house when it was used. It appears the previous owners used a stove on one side and probably just left the glass doors closed on the other.

Pull out he steel plate and stove pipe that is there. Decide where you want to put a stove, which stove you want, and run a proper stainless steel liner down the flue. The stove will define what size liner (6 or 8 inch). Is the floor downstairs a concrete slab? Look at rear exit stoves. Put it on the floor directly in front of the fireplace opening with a tee in the old fireplace and a straight run up the flue. Put a block off plate on the bottom and a properly sealed cap on the top. For an internal chimney insulation is not necessary but with that large of a flue may be helpful. You might consider removing the old hearth so the stove can be placed closer to the old fireplace. Then close up the other side. Either have a mason do it or have a steel plate made and bolt it on.

Question 1. Yes, the over-sized flue with the stove outlet poorly connected caused a lot of creosote. Cool air mixed with the exhaust gasses and they condensed.

Question 2 & 3: See above...

Question 4: Yes... That is what liners are used for. Clean the flue well and run a liner sized for the stove you choose.

Question 5. Definitely a DIY job. Get a liner kit and follow the included instructions. Ask here with any questions and the members will guide you.

Question 6. Tell us a lot more about the house, room layouts, local climate, ... and the members will make stove suggestions... In my opinion, depending on room sizes, a freestanding stove downstairs and an insert upstairs...

KaptJaq

 

[Charles1981]

Question 6. Tell us a lot more about the house, room layouts, local climate, ... and the members will make stove suggestions... In my opinion a freestanding stove downstairs and an insert upstairs...KaptJaq

Wow thanks for the quick reply. Is rigid pipe ok because it is such a large straight shot of a flue? It seems rigid piping is cheaper as well.

This is in Michigan near Lansing. So pretty cold climate. The house is baseboard heated (but is well insulated because we viewed it at 18 degrees outside with baseboards set to 60 and it was surprisingly warm). Again its a basic 1050sq foot rancher layout with walkout basement.

The basement floor is concrete. You can see at the upper chimney photo the previous owner cut two passive vents into the floor board and then respective basement ceiling to allow further air flow upwards. There is a spiral staircase dead central in the house and a Ceiling fan mounted directly over the spiral staircase I am assuming to aid in moving air from the basement upstairs as well. The basement is finished as far as dry wall goes, but no flooring has been done (two sides of the foundation are up against soil, there are no downspouts, and there is improper grading of soil up against these two sides, so there is efflorescence). There are no serious signs of water damage, but I am thinking this may be why the basement isn't finished (no flooring) and that we are going to have to correct the moisture problem (hopefully downspouts away from the house and re-grading will do it and not digging down to the foundation to install french drains!) however there is no moisture damage to any of the drywall so fingers crossed.

While I would love two stoves I can only feasibly do one at the moment. If i attach a stove where the "back window" has been punched out it lies directly under the living room and kitchen (open floor plan) with the spiral staircase in between the two.

I realize stoves in the basement can have trouble getting air upstairs and to the rest of the house, but I am hoping with a large enough stove and the central location of the chimney and the small size of the house I can effectively heat a majority of the house without difficulty... How effective do you think those passive floor vents are in transmitting heat upwards?

Thanks again,

Charles

 

[KaptJaq]

Is rigid pipe ok because it is such a large straight shot of a flue? It seems rigid piping is cheaper as well.

Rigid pipe should be fine. The advantage of flexible is that you take the whole roll to the roof, unwind it and slide it down. It is also forgiving of minor curves in the flue. Rigid is easier to clean but you have to assemble the sections as you slide it down.

This is in Michigan near Lansing. So pretty cold climate. The house is baseboard heated (but is well insulated because we viewed it at 18 degrees outside with baseboards set to 60 and it was surprisingly warm). Again its a basic 1050sq foot rancher layout with walkout basement.

What is the room layout? Especially downstairs where you would like to put the stove. Big enough room not to be baked out by a large non-cat stove? Or do you need a catalytic stove to give you long slow burns?

The basement floor is concrete. You can see at the upper chimney photo the previous owner cut two passive vents into the floor board and then respective basement ceiling to allow further air flow upwards. There is a spiral staircase dead central in the house and a Ceiling fan mounted directly over the spiral staircase I am assuming to aid in moving air from the basement upstairs as well.

Concrete floor saves having to build a thermal resistance hearth pad, opens up a lot of stove possibilities. The spiral stairs and fan will move a lot of heat upstairs. Most here like a small fan at the top of the stairs pushing cold air down towards the stove. Depending on the total house layout the floor vents might not help the natural convection too much.

While I would love two stoves I can only feasibly do one at the moment. If i attach a stove where the "back window" has been punched out it lies directly under the living room and kitchen (open floor plan) with the spiral staircase in between the two.

If you are doing only one stove then consider where you will spend most of your time. A nice warm basement is useless if you are always in the upstairs living room. With the spiral stairs near the stove you may be able to move a lot of heat up to your living area but you will not know until you try. If you are a DIYer you could try putting the stove downstairs. Minimal expenses (no hearth pad, etc). If you can't move enough heat upstairs then move it to the upstairs fireplace. You should be able to move the liner to the other flue.

When you have resources for a second stove then do both. Since upstairs has a wood floor you will have to worry about a hearth pad, ember protection, and thermal resistance to the stove's specifications.

I have two stoves, one up and one down. With two stoves I don't have to push either one to hard so the house is evenly heated. My downstairs stove is near the stairs and, when the weather is mild, can put enough heat upstairs to keep the house comfortable. Every house is different, it takes a little trial and error to get it the way you want it...

KaptJaq