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As a homeowner (and chronic DIY remodeler) I have installed no fewer than four B-vent zero-clearance fireplaces in various homes over the years. Other than the fact that they do look a little “manufactured” compared to a bricks & mortar FP, they work beautifully and are a breeze to install. I had the pros install the first two and stood quietly by; did the third & fourth myself. Actually, IMHO creating the exterior “chimney” framing around the B-vent was a more challenging project than the FP itself. Another great advantage is that you can run the B-vent back at a 45-degree angle (depending on your local code it may be as much as 60 degrees, I’m told), which gives you room over the front of the firebox for an art niche or TV alcove. The interior “firebrick” surface does look better after it collects some soot. Also, if you sheathe the surround with tile/marble/granite (I’ve had ’em all) to reduce the amount of metal facing that shows, and dignify it with a nice mantle, they can look pretty darned good. There are other nuances such as exterior cold-air intakes, gas starters, heat circulating devices, etc. Personally I always have a plumber install a gas starter, but it’s certainly not necessary. My two cents! — Buck
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As a homeowner (and chronic DIY remodeler) I have installed no fewer than four B-vent zero-clearance fireplaces in various homes over the years. Other than the fact that they do look a little "manufactured" compared to a bricks & mortar FP, they work beautifully and are a breeze to install. I had the pros install the first two and stood quietly by; did the third & fourth myself. Actually, IMHO creating the exterior "chimney" framing around the B-vent was a more challenging project than the FP itself. Another great advantage is that you can run the B-vent back at a 45-degree angle (depending on your local code it may be as much as 60 degrees, I'm told), which gives you room over the front of the firebox for an art niche or TV alcove. The interior "firebrick" surface does look better after it collects some soot. Also, if you sheathe the surround with tile/marble/granite (I've had 'em all) to reduce the amount of metal facing that shows, and dignify it with a nice mantle, they can look pretty darned good. There are other nuances such as exterior cold-air intakes, gas starters, heat circulating devices, etc. Personally I always have a plumber install a gas starter, but it's certainly not necessary. My two cents! -- Buck
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Andrew,
Buck is right. They are a breezee. Just bear in mind when you are framing that you need access to install the vent. Also don't forget the fire stop at elevation changes & all combustibles 2" away.
*Hi andrew, Installed my Marco brand woodburning tin box about 5 years ago. Had fun with the exterior chase; it's a 17'high 4' wide climbing wall. bombproof eyebolts tied into the frame just below the cap. I couldn't specify the vent right now but, basically it's an installation with specified clearances all around. Watch the hearth to fireplace joint where you need to prevent embers dropping through a crack onto combustibles. Pull a permit and make sure the bulding's insurer endorses the change. Mary and I use the fireplace alot every year with no problems. The interior finish is where you get to show your stuff, and design and build a beautiful surround. Joe
*Putting one in now. Built the frame "chimney" chase first. Had a lot of fund running the double wall metal chimney sections in after the fact. If I were going to do it again, I would keep the chase open on one side until the chimney sections are in.
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Andrew, reading Joe's post reminded me that I just installed a Marco brand gas firebox in a rental unit I own - a similar procedure. Out here the clearance tolerance to combustables is only 1", gas or wood. As Steve says, absolutely positively install your B-vent before you finish your chase! Plus becuase this one's gas & not wood-burning, the vent only needed to project 18" above the roof line where it emerged, not the ridge. No earthquake bracing required, either.
I installed a gas unit in the rental because of concerns over combustables and must say I am impressed with how good the unit looks. Marco includes some sort of steel-wool-like substance that you tear up into small chunks and sprinkle along below the main flames to simulate embers, and by golly, they actually do glow like that. With the optional glass door kit, once this baby's on you have to do a double-take to tell it's not a real wood fire. One final note, I installed it in a corner of the living room at a 45-degree angle. A bit trickier framing job. but the angled installation gave me room for a serious built-in entertainment center above the firebox (a full 19" deep). Had some custom paneled wood doors made to fit the alcove -- dresses it up, and you don't have a TV staring at you when you're not using it. Overall, a highly desirable addition to that rental.
Buck
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We are getting ready to install one of those fireplaces soon, and I was planning to sheath the interior of the cavity where it will be installed with 1/2 inch backerboard, and maybe line the chimney housing with the same stuff too.
Based on past use, we will probably use our fireplace a lot, like all day for several days running without much time to cool overnight, and mostly oak fuel which burns pretty hot, so I thought the backerboard would give a little extra fire protection. I wonder, though, if there is some other product that has more insulation value on top of being non-combustible. Thicker is OK because we haven't started the framing yet. Any suggestions?
Jay
*Y'know, while these save a bit of dough to begin with, I think you'll regret it later. My mother in law (she's wonderful so don't start) has a house built in the late 60's with two steel fireplaces. They're rusty and old and I can't help but wonder when some part will finally oxidize through and burn the house down.I recently priced up framing, trimming, siding and capping a chase, then installing a metal box and the chimney, and guess what? Not much less than having a brickie build a rea one, that looks substantial inside and out and will hold up over the long haul.DougPS Andrew, email me for info on a local supplier (if you're ni No. VA)if you're doing a zero-clearance.
*jay, ever thought about stand-offs for that backer bd? to let air circulate on the backside. not that it's necessary, but then again, neither is the backer bd. so they say.
*You might check the Breaktime thread "ACC Concrete Block" which discusses Precast Autoclaved Aerated Concrete. It is a type of precast concrete with insulating properties. I have no experience with it and don't know if it is made thin enough for what you want. One of the posts indicated that it is only available to those who have training in installing it, so you might have to do some talking to get some even if it is available in a suitable size.
*Not so sure about the cement board as a fireblock ... I haven't heard it used or recommended for the purpose, and the cement is basically bound up only by a jacket of flammable fiberglass. I've thought about putting some double type-X rock up a chase with periodic sheet-metal fireblocks, but mostly to limit fire traveling in the chase and to contain carbon monoxide from the B-vent -- the vent itself is not, of course, going to burn.
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Andrew: did you check out November's issue of This Old House. Tom's installing a zero-clearance fireplace :^) Maybe check out TOH website,....if you can find your way through it before getting fed up!
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Actually, I (ahem) get the mag and read the "article." Just 2 pages ... figured the 'perts here knew more than they did anyway.
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Gee, Andrew, Hope you didn't take me seriously. I'm only a wannabe-carpenter, and I find TOH seriously lacking in details on projects. At least, I don't subscribe to it, just pick it up every few months to remind myself why I don't get it the months inbetween.
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No, don't worry, I subscribe. From a photographic and graphic design standpoint I think the magazine is excellent, and I've picked up more than a few ideas from looking at it. A cover story they did on these remarkable cherry spiral staircases may get me a very nice job from the homeowner I showed it to. Not how-to, however ... though DeSilva's practices are worth listening too provided the editors don't mangle them too much. i liked when they explained that stringers were "those zigzag things under stairs" -- at least it showed who the target audience was. But that audience is our employers, esp. the upscale ones with nice work.
It's just one of those things, like buying Playboy for the articles, where ... people might get the wrong idea. Capisch?
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... by which I mean the B-vent woodburning ones. I did not even know such a thing existed until a client brought it up -- I'm still unpersuaded by the gas simulated ones. Any experiences, good or bad, from builders or homeowners?
Just curious ...