Chimney questions

[RogerT]

I own a property that has a brick chimney that extends maybe 10 feet or so above where it comes through the roof at the back of the house. The property that I own is a "twin" home -- meaning two single family homes that are attached with a common wall in between -- I own the home on one side and my neighbor owns the home on the other side. My side is a rental property that I have rented out to a family, and my neighbor on the other side owns his half and lives there.

The chimney is actually two chimneys in one. It goes up along the inside of the back wall along the party wall line, and my half of the chimney is for my home and the other half is for the neighbor's home. The combined chimney was originally brick and it now has stucco over the brick on all four sides. The stucco is starting to deteriorate in a few places and the chimney looks like it may be leaning a little. So, I am going to have a chimney person look at it and tell me what he thinks it needs etc. It may just need to have the stucco repaired or redone or it may need a lot more than that.

What I am wondering is, if it turns out that the best thing to do is to take down the existing chimney and replace it, are there other types of chimney construction that could be used for the replacement other than brick or block? Both houses have aluminum siding and no brick, and the chimneys in the back, so there is no need for a new chimney to be made of brick or anything fancy. Even metal chimneys would be fine with me (and probably my neighbor) if there is such a thing for this type of application.

The heaters for both houses are gas-fired steam radiator heat and the hot water heaters are gas hot water.

I found the following link that gives some guidelines for how high the chimney is typically supposed to be in relation to the roof:

. I didn't do any measuring, but if it needs a new chimney and it is legal and safe to have the new chimney be less high than the existing one, I would go with that.

I'll be asking the chimney person these same questions, but I thought I'd also post the questions here beforehand to get any ideas or suggestions anyone may have.

Thanks.

[Don Phillipson]

Because such work would require a building permit, your first stop should be the local building permits office. The local Fire Code may helpfully narrow your choice.

[Ed Pawlowski]

"RogerT" wrote

I'd go with brick or stone myself, but there may be other factors I don't see from here. In my area, there are a lot of houses build in the mid

1700's and up. The original chimneys are, for the most part, still intact and working proving the durability of masonry. Some have been relined. A good chimney guy is the best to see and assess the situation though. Metal may be a less costly alternative if it has to come down.

There may be a reason for the height also. Prevailing winds or other topography may affect the draft. so check things before you arbitrarily shorten it.

[Michael B]

[trader4]

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In the process, I'd consider the age and efficiency of the existing boiler and the water heaters. At some point, if you were to go with new units that are direct vent, you'd no longer need the chimney to be functional, though you'd probably still have it for aesthetics.

Along the lines of Michael's sizing issues, if you replace the boiler with a direct vent, the chimney will be too large for just the water heaters and will need to have a chimney liner installed. Just some factors to keep in mind as you go through the options.

[ransley]

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There is no such thing as a condensing Steam Boiler that release low temp exhaust in his size. The best you get is 83% in the homeowner range. Commercial even at 1,000,000 btu are best 83%. Industustrial, im sure they have them. Convert to HW? then you can get leaks as steam is 2-4lb and water is 15-35lb.

[RogerT]

Thanks for all of the replies. I guess I'll need to wait and see what the chimney person tells me as to what my chimney may need, what the options are if it needs to be taken down and rebuilt, etc. I haven't found anything much on the Internet regarding non-masonry (a.k.a. factory built) replacement chimneys.

Maybe all I'll need is to have the stucco around the chimney repaired. Since the chimney extends fairly high above the roof line, I have a hunch that this may end up costing more than I had hoped, but I'll have to wait and see.

I won't be replacing the heating system or converting it from steam to hot water (it's a one-pipe steam system now).

[hrhofmann]

Please let us know the outcome of this.

[bob haller]

I assume you have no working fireplaces?

If so it might be cheaper to upgrade furnace and hot water tanks in both units and just remove the top of the chimney completely.

thats pretty popular around here, far cheaper than rebuilding and relining, no flashing or chimney to maintain, lower utility bills, with condensing furnace.

the roofer just drops he debris and bricks down the now no longer used chimneys, plywood over the hoe once the chimney is below roof level.

many do this all the way to the ground, to get more interior space....

of course you have the other owner to deal with. but you should at leastprice all the alternatives

[ransley]

There is no condensing steam unit that I know of for a homeowner, he needs a chimney. There are condensing boilers , but at 140 is peak efficiency, at 180f you save only maybe 5% at steam or over 212 you dont condense.

[RogerT]

I will do that.

[RogerT]

No fireplaces in either property.

Thanks for the ideas. I'm sure I won't be doing the option of eliminating the chimney completely. Even if there is such a thing as a high efficiency direct vent steam heat boiler (I don't know if there is), it would mean both me and my neighbor getting new heaters and I know my neighbor will never do that. In fact, most likely, whatever I have done with the chimney(s), I will rpobably pay for the whole cost myself.

I know what you mean about the chimney removal process. I removed and old no-longer-in-use chimney that way in another property. In that case, as I worked from the top down I dropped everything down the chimney into a walk-out basement. Then I had someone wheelbarrel it all out onto a trailer and haul it away.

[Michael B]

[ransley]

Please show me a Condensing Steam Boiler with Low Temp exhaust, I looked.

[trader4]

I agree with your observation. When I suggested considering a high efficiency direct vent, I was thinking hot water, not steam. You're right, in the home class units, looks like there is no such steam animal. Which I guess makes sense because to extract all the heat out, it has to go to someplace colder. With the higher the temp of the fluid, eg hot air, water, steam, the harder it gets to do that.

[Michael B]

Same here. Although I know a guy in South Dakota that has some secondary heat exchanger setups to get some of the waste heat before it is lost in the stack, on a unit that is easily well over 60 years old. He swears by the name of Dan Holohan.

[ransley]

Im looking for a new steam unit for a 12 unit, even at 1,000,000 btu I cant find one.

[ransley]

Dan Holohan of Heating help, and The Wall, is the probably the best regarded, most well known expert for Steam, I have his books. I have a

1954 Kiwanee steam boiler