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Chimney Chase

lynchfh's picture

I've got half a dozen carpentry and building books, I got FHB back to No 44, I've searched on line and I can NOT find anything on how to build a chimney chase.  I can't get a building dept. to give me any info and they have to inspect it!!  I know how to put in fire-stops, etc. it's the general construction.  Does anyone have a source?  I've just finished an attached patio and getting ready to put in a DIY kit  masonry fireplace, with a metal flue.  I'd appreciate any help I can get.

All I know is that about 20 (post #207087, reply #1 of 6)

All I know is that about 20 years ago, in order to make the inspectors happy in a H4H home I was working in, I had to figure out how to line the inside of the chase with drywall.

Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

Build it just like any other (post #207087, reply #2 of 6)

Build it just like any other wall.  You might have to line the bottom 4 feet with cement board but I've never had to.

Florida Licensed Building Contractor, 50 years experience in commercial remodeling, new homes, home remodeling and repairs and all types building maintenance.

The fireplace will have (post #207087, reply #3 of 6)

The fireplace will have clearance requirements that have to be followed - often it's simply an inch from any combustible materials if it's the double wall type that is bringing in combustion air as well as exhausting out the center of the pipe.  The chase can be built like a wall, but to keep it insulated it's much better if you line the chase with something.

When I built a chase I make it out of 2x6 to allow a decent amount of insulation and line it with osb.  Fiberglass is a poor insulation in cold climates in the best of circumstances and if you essentially vent half the insulation to the inside of the chase it's really crappy.

Pay close attention to flashing and weather proofing since chases are probably the most common place to find leaks and poor craftsmanship.

If I could edit my location it would say I'm now in Reno :-)

Thanks (post #207087, reply #4 of 6)

Thanks, guys.  I hadn't thought about lining the inside with sheetrock, that'd add stiffnes and shear also.

outside fireplace? Insulation? (post #207087, reply #5 of 6)

You might want to clarify your porject.  Is this an outside fireplace?  People here are talking about insulation which I don't beleive is necessary for an outside chimney.  Some might like insulation in either case to keep teh flue warm, bt if it is an outside fireplace I would guess the flue is pretty short and cooling would not be a problem.


lol - you're right - this is (post #207087, reply #6 of 6)

lol - you're right - this is outside!  I don't think I'd insulate anything either :)

If I could edit my location it would say I'm now in Reno :-)