Using an oil burner masonry chimney for a small wood burning fireplace

[SandroJr]

I live in a small city and cannot find anyone to give me an answer. The chimney is on the inside, on the hallway wall. It has a base in the crawlspace of 30”L X 26”W X 28”H (to the floor joist). It then is 16.5” X 16.5” to above the roofline. The internal diameter of the clay-lined flu is 6.5” X 6.5” square. Opposite the hallway wall is the living room. I was hoping to make a real small wood-burning masonry fireplace (like a Rumford?) using the existing chimney that served an oil burner that now has been removed. The house is a one-story, 1K sq. ft Is it possible? Can you offer any assistance in how it can be done? Plans? Thanks for the help in advance.

 

[joshuaviktor]

Yes, we can help. No, don't do it. Ok, listen here. That is a low pressure masonry chimney, and not designed to handle the heavy volume of extremely hot gasses and creosote that a fireplace can generate. But keep heart. It is Potential that you can use the chimney as a guide for some double wall pipe and connect it to a small wood stove, which would generate MUCH more heat than a fireplace anyway.

I have never done such a conversion, but depending on the distance to combustibles, and the type of liner pipe you use, it might be just fine. Your best bet is to get an experienced installer to look at the chimney, and see if it is suitable. Elk, chime in on the law, and the type of pipe accebtable in these circumstances. This guy gave some good measurements, and deserves any thoughts we can give him.

NOte! I said potential, and might. I did not say guaranteed. Make sure, then make sure again, then have it inspected. Hell, call your town inspector first, and ask him to stop by. Might be a good idea. Get his take on the situation.

Good luck,

Joshua

 

[elkimmeg]

If that flue line could be used you could have a 17" /17" opening The floor would have to be removed to a distance 20" in front of the hearth Not just the wooden floor but all the framing members would have to be removed and headed off, so that a poured concrete hearth can be installed in a crib like setup. While at it since ther is no support for the additional concrete bricks weight a footing and block or brick structure would have to be built to support the additional weight since the floor is not designed to carry the load and was removed for the poured hearth. The chimney would have to be broken and supported to create the fire box throat and smoke shelf so some kind ot steel I beam would be used to support the chimney above the work area . There would be a damper issue. You would have to find someone to custom cast one for the 17 /17" opening. If it sticks into the existing hall the hall requirement still have to be met. One cannot create a structure and make other parts non comforming. You would need 4 feet infront of the 2' hearth to remain conforming. By the time a new footing is constructed to support the aditional weight and the existing floor length is broken out to build and rig the support the existing chimney above $10,000 will cost will be passed That does not factor in removing additional walls to make the hall way conforming as there is a good chance those walls are structure bearing. The end result it would have become cheaper to remove the entire chimney and start new with a flue size that would be larger enough to support a decent size opening.

As Josh had indicated, there is a cheaper way though a compromise, that can get some heat and attmosphere . Vermont castings makes a stove like the Intrepid II, that is a wood stove, but with the accesory fire screen. It can be used and viewed as an open fireplace by opening the doors. If you want a bigger unit the Resolute Acclaim or Defiant all have screens that can be used for open opperations and viewing. Your flue size is correct to support these stoves the Acclaim and Intrepid. The larger stoves require 8" flues which may not be possible to comply with code dues to your interior dementions of your existing flue. Cost of the intre[id approved hearth pad and some single wall pipe probably less than 3k installed, figuring cutting into your existing chimney for the flue connector Heat benifit priceless but probably a dent in your master card.