Questions about installing new masonary or metal wood stove chimney during renovation

[MI Feller]

Currently have a small wood burner with rear vent. Six-inch stack elbows than goes into 8-inch metal chimney and through ceiling. Good performance over many years. Drawbacks: Small attic gets very warm and humid. Ice dams form along roof. Difficult to inspect where passes through attic. Cleaning is dirty affair--- partially done from below in living room. Solution being considered along with new construction: Erect cement block chimney in new entrance hallway (opposite wall behind stove). Brick exterior for appearance. Thimble through wall to chimney. Leave ceiling above open (cathedral style) for added visibility where passes through roof. Back-fill from ground to floor level. Install clean-out a foot or so above floor. Any problems apparent in this scheme? Also, (1) Is a 3-foot horizontal distance from stove vent into chimney acceptable for decent draft? (2) Is a masonry chimney just as durable/weather resistant--especially above roof-- as a metal one? (3) Am accustomed to running a brush from roof all the way down the metal chimney. Would chimney with a thimble/pipe protruding into it present any serious cleaning issues? Could switch to a framed-in metal chimney if you think metal superior. Thanks for any ideas.

 

[wellbuilt home]

If you are making the ceiling cathedral I would go with a cathedral roof support and 6" flue .
You can run 6" steel stove pipe from the stove up .
Your chimney flashing should be vented around the flashing collar.
I would love to build cement block chimney all day long we charge big money for them , but the SS really work great .
I have a 8" flue that has been burning 24/ 7 for 20 years and we have had no problems
John

 

[dvellone]

Currently have a small wood burner with rear vent. Six-inch stack elbows than goes into 8-inch metal chimney and through ceiling. Good performance over many years. Drawbacks: Small attic gets very warm and humid. Ice dams form along roof. Difficult to inspect where passes through attic. Cleaning is dirty affair--- partially done from below in living room. Solution being considered along with new construction: Erect cement block chimney in new entrance hallway (opposite wall behind stove). Brick exterior for appearance. Thimble through wall to chimney. Leave ceiling above open (cathedral style) for added visibility where passes through roof. Back-fill from ground to floor level. Install clean-out a foot or so above floor. Any problems apparent in this scheme? Also, (1) Is a 3-foot horizontal distance from stove vent into chimney acceptable for decent draft? (2) Is a masonry chimney just as durable/weather resistant--especially above roof-- as a metal one? (3) Am accustomed to running a brush from roof all the way down the metal chimney. Would chimney with a thimble/pipe protruding into it present any serious cleaning issues? Could switch to a framed-in metal chimney if you think metal superior. Thanks for any ideas.

I think the max horizontal run from the stove vent into the chimney should be specified by the stove manufacturer. All things being equal (and as a Stonemason I have a definite bias toward masonry construction), you'll save a bundle on materials and labor going with steel. If you do it yourself in masonry you'll save the labor expense, and it'll end up costing you less, but that steel sure is light and goes up pretty darn quick and makes almost no mess at all. Unless you're well versed in masonry construction, or the masonry is an integral part of the architecture of the space or element of design as in a fireplace, the steel will save you a lot more than it's added expense.

 

[MI Feller]

THANKS. APPRECIATE BOTH RESPONSES. Good to hear you like masonry. Looking to improve home and resale value. As part of the plans I'm drawing up to show a builder, a nice interior masonry chimney probably won't hurt much cost-wise. Will check with local stove dealer on allowable distances to chimney. Could move stove closer, but would require LR renovation & new flooring. Curious about customary masonry flu sizes. When we installed metal 30 years ago, dealer recommended going from 6" into 8" for a better draft. Maybe with masonry, 6" all the way is enough? Stove is small but will get a little bigger one some day. House has grown, but still only heating around 1,000 square feet. Have read there's a 2" setback from combustibles on an interior masonry chimney. Wondering if that has to be visible space, or could be somehow filled with brick. Other suggestions welcome. Thanks Much.

 

[berlin]

Masonry is far more durable and looks much, much better. properly sized and built it will outperform and outlast metal chimneys with one notable exception - a chimney fire. the clay tile liner is often installed too tight, and with much creosote buildup, a hot chimney fire will cause stresses during expansion and the tiles will crack. Obviously if you have an epa stove, burn properly, and be sure to keep your chimney relatively clean you won't have a problem. I have seen 304 and 316 stainless chimneys pinholed, perforated, and in one case completely destroyed in only 2-4yrs with coal or oil exhaust; with a woodstove you may get 20 years out of it, but a properly built masonry chimney won't need any maintenance for at least twice that. If you want the top (exterior) of a masonry chimney to last pour a concrete (3"+ thick) crown or use stone, DO NOT use mortar. Use 8/8 tile flue, or 8" round tile.