Rebuild masonary chimney or install class A?

I would not rebuild a masonry chimney. I spent 1000$ to have mine removed, plus waste the 500$ liner, and then installed a free standing stove with class A. Those masonry chimneys are always falling over, crumbling, cracking, needing to be repointed, etc. and my oh my can they be expensive to build. If they weren't so dang pretty when new I don't think anyone would have them. The exception of course is a masonry heater that has some redeeming qualities.

The answer is "it depends". My house would look kinda silly w/out the big brick chimney sticking out the roof, because big old Vic's are supposed to have giant honkin' (pretty?) masonry 3-flue chimneys... If you have a simpler cabin, cape, or ranch style house w/ a single-flue chimney and won't be affected by the looks, or the impact of all that masonry demo internal to the house, then go for removing it.

Now one curious thing is you mentioned no flashing. Is it there? missing? never existed? If you had no flashing, it's not a shock that it's leaking. tar alone has a fairly short lifespan. And adding more tar doesn't mean you'll get the same lifespan repeated, as compared to new...

Again, my house - needs the chimney - i had it all repaired, re-capped, and rebuilt a couple years ago, and lined, and spent about $1000 iirc. But I happen to be very fortunate in that I have a very good mason who works pretty darn cheap.

If the flashing is all proper then you don't need any tar IMO. The tar might be causing the leaks by backing water into places that it shouldn't be. Along with the cost of replacing the brick with class A also consider the cost of demolition. Even the sheetrock work where the old fireplace was.

You might want to have a chim sweep see if he / she can do a video inspection of the actual tile flue, i.e. run the camera betwwen the s/s liner and the tile liner. Object would be to see if you have damage inside the tile flue. Also, can you inspect the portion of the chim. that runs through the attic? If the only damage is at / above the roof line, you're probably better off having a good mason repair the damage. If you have damage below the roof line, you'll want to seriously consider repacling the chimney w/ s/s. If you want the traditional look above the roof, you can have it "veneered" with face brick or stone, etc.

Whichever way you go, have it done right and you'll only have to have it done once.

Peace,
- Sequoia

Never seen a chimney come through a roof without lead flashing... should be sheets of it, bent and laid down around the edges of the chimney. They go from under the shingles, up the side of the chimney to the first or second course of bricks. There, the lead is mortared into the joint. This provides a surface to seal against between the asphalt shingles or steel, and the lead.

I don't believe a brick and mortar chimney expands or shrinks to much degree from heat and cold. It's why brick and mortar is used. Instead, generally speaking, the shingles and tar around the chimney expands and contracts with summer heat and winter cold... loosening the seal between the roofing and the flashing. Generally, aplying some tar right along the edge, where the crack is, is all it takes to seal that up.

I've seen some poor chimneys, and generally it is because of materials and construction methods. There's two of them in my 150 plus year old house, and both are in pretty darned good condition. Inside and out... I'd be surprised to see the "modern day" methods and materials still around in 150 years. The best of it won't last fifty years.

A good mason can tell you whether or not you should think about demolishing an old chimney and replacing it. Might be cheaper to repoint the exposed areas, recap it, and bust out the clay liner, then reline it with whatever you want to...

ikessky said:

The current chimney extends from the basement floor to the roof. The only sheetrock I would have to remove is in my bathroom closet, which is where the chimney comes through on the ground level of the house. I would do the demo and waste removal by myself. There is no existing fireplace to remove or block off. The chimney was used to vent a wood stove, the the NG furnace, and now an add-on wood furnace.

I spent my lunch hour on the roof with a tube of tar. It looks to me like the chimney probably expanded and contracted throughout the burning season to a point where it loosened and cracked all the caulk/tar from around the chimney and shingles. I smeared a bunch of the tar in the areas where it used to be, but just as a temporary fix for the next few weeks/months. I'm going to call a local mason that will do a free estimate and see what he recommends I do with the actual chimney. There are a few cracks in the bricks, but it's the crown that is falling apart. It doesn't look like it was made very well. Looks like large stones set in mortar rather than the nice formed concrete ones that I've seen other people have installed on their chimneys.

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I myself think the crown itself is worth fixing. Don't know what it costs where you are but I repair crowns all the time and I generally charge $450 to $800. If you compare that to the cost of putting in a class A. As long as your flue is intact and looks in good shape and your brick is still decent. Now if no flue or bad shape then maybe go with the class A. As far as the flashing just needs all the old pulled off altogether and new flashing, shouldn't cost too much.

Had chimney rebuilt last year and stainless insulated liner installed (6") $4000. 40 year old chimney. Cause of problem (much like your description of leakage), older furnaces and water heaters had standing pilot flame so always had some heat going up flue year round, kept it dry. Some 10 or so years ago new furnace and water heater with electronic ignition. No heat to keep dry, condensation forms and the motar gets leached out and starts crumbling progressivly getting worse. Due to various city codes I had to have redone like it was externally otherwise there were less expensive alternatives. Additional note: shortly after mine my neighbor was complaining about a leak he could not find in his roof, He had had several roof guys out to no avail. House is about 35 age wise. Suggested problem might be chimney ( one of those 8' x3' wide and runs from the top of first floor past second, kind of a modified A frame type home). Yep it was chimney, masons were there for about a week or so. They were doing the repairs in Nov., Gets pretty chilly around here at that time of year.

If the liner is still in good condition you might be better off just fixing up the shell and installing another chimney cap. I think a UL 103 HT chimney might give you better performance and more safety. But everything depends on what appears on site. That little gap between the liner and shell allows the liner to expand and move a bit. There must be a drip edge under the cap to keep water off the shell. But it's unavoidable to do some repointing periodically. If the liner is not in good condition, I would then lean towards alternatives. At the same time, I don't anything about what people charge to do the work.

I think clay liners should be banned...so does the local fire chief...said so when he came to put out a chimney fire at our house...though I did have it out by the time they arrived....Had just bought our property and had cleaned the chimney a couple of times.....crazy as it seems I like to clean it every 2 or 3 weeks...the problem was the previous owner must have idled his stove a lot...thought I was cleaning it but was super glazed and probably an inch thick...just seemed clean....then whooooosh...put a stainless liner down it but the draw is useless so am going to tear it down and put in insulated...frame it with metal studs and cover in cement board then fake brick it above roof line....I know I know but a bricklayer friend said why spend the bucks on brick....which is what I was going to do....never really liked the look of metal chimney...you mortar the brick and cap it and voila..who can tell way up there.......

You might consider demoing it below the roof line, capping it and roofing over it. Obviously, you would also need to mortar close the basement access as well. In some cases, this is a lot cheaper and more practical than completely removing it.

If the masonry chimney is demolished to below the roof level and capped over, why is it important to mortar off the basement access hatch?
I am in the process of lowering a masonry chimney to ceiling level, where I plan to insulate it off and use it as thermal mass for a free-standing woodstove that is installed in front of a large expanse of the exposed masonry within the house.
The masonry chimney now serves no purpose and has no appliances connected.

You may want to check out www.chimneysaver.com as they have a line of products for your particular ills. I'm not sure which of their products would be best for you, but they have a chimney problems checklist you can go through and it will suggest products that may help you. Things like "CrownCoat" and "CrownSeal" come to mind.

I reckon it wouldn't hurt to check it out. Click on the products link at the top. No, I don't work for them.

dougstove said:

If the masonry chimney is demolished to below the roof level and capped over, why is it important to mortar off the basement access hatch?
I am in the process of lowering a masonry chimney to ceiling level, where I plan to insulate it off and use it as thermal mass for a free-standing woodstove that is installed in front of a large expanse of the exposed masonry within the house.
The masonry chimney now serves no purpose and has no appliances connected.

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You dug up a really old thread so people's answers may be odd.

The reason to cap off the chimney above and below is that it will act as a chimney to suck basement air up into the attic. Air movement is the problem. When you heat the mass with your stove the air inside will rise and suck in air from below to be released as stinky air into the attic.

Thanks, I understand.