My home (in East Texas, built in 1885, two stories, pier and beam) has two chimneys, one of which I would like to reopen. Apart from information gleaned online, I have no experience with chimneys or fireplaces, be they wood or gas; I just know I like the heat and the smell of burning wood.
The chimney is in the center of the house, and is about 40 feet tall, ground to top. It is currently capped at the top, and the fireplace is bricked in (at the damper). I have no idea what the condition of the inside of the flue is like. There are no cracks in the outer bricks, though the mortar is slightly crumbly, at least the portions in the crawlspace and in the attic. The fireplace itself is in great condition; the inner and outer hearths have no cracks or sag, and the fire box looks strong. There is not a clean-out, nor an ash pit.
Assuming the chimney can be used at all, how much effort/material/cost would it take to reopen the chimney and safely restore it for use as a wood-burning fireplace? A weekend DIY job, or a hire-an-expert-and-pay-for-his-retirement job?
If the chimney or fireplace is impossible to restore and/or safely use, would it still be possible to install a natural gas burning inset, and use the chimney as an exhaust vent (including adding a standard metal vent inside)?
Best Answer
I would really suggest that you should hire a local expert to come out to your place to give you advice on the chimney condition, design and safety. I am quite sure that there was good reason to cap off and close up the chimney and fireplace in the past and it is highly unlikely that you will come to an understanding of the reasons without some seasoned advice.
Some things to consider:
There was a time when many chimneys were built by laying in the bricks with damp sand that was mixed with lime and horse hair instead of regular cement bearing mortar. Aging by wind and rain could wash out this material in the upper part above the roof line leaving the bricks with open spaces from inside to outside.
Many old chimneys were built simply as a stack of bricks without any specialized flue liner at all. A good quality modern chimney would have a decent flue liner that was mortared in with a high temperature silica material that does not degrade with heat.
It is an art to design and build a chimney installation that will function well with a fire place. It is really impossible for anyone to evaluate your installation without being there first hand to attest to the the quality and design.
Advice on whether to use some type of natural gas fireplace insert with using the existing chimney as a holder for a vent stack will depend on several factors that cannot be ascertained without direct evaluation. Structural safety of the chimney would be one issue that I can think of. Another would be whether the chimney opening can accept the insertion of a vent stack of sufficient size (diameter). Yet another is the uncertainty of maintaining the joint integrity of the vent stack as it is assembled piece by piece, up to 40 feet total, and lowered down into the chimney from above.