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Chimney & Fireplaces/Cutting compound-angle slope on firebricks

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Expert: - 3/24/2007


Question
Hello,

I built a Rumford fireplace in tradeschool a while ago, but I haven't had to
build a fireplace for over 5 years.  I've forgotten how to do one detail.  How
do you cut the compound angle on the sidewall firebricks (to accomodate the
inward-sloping back wall)??  Do you dry-stack the sidewalls first, then use a
chalk-line to mark the correct angle up to where you want it, then
disassemble the wall and make the cuts, and then lay in the back wall?  This
is the only way I see how to figure out the correct angle that will bring your
back wall up to where you want it, just behind the damper... How do you guys
do it?

Thanks for your time

Luc


Answer
Hi Luc,

IF you're angling your rear Rumford wall (we don't since we modify the breast and throat areas to provide for laminar airflow), you'll use an adjustable angle guide and a level.  It sounds like you're actually building a modified Rumford.

A true Rumford has straight vertical walls and will work much better than what you're trying to build.

We've found that the true key is smoothing the breast area and reducing to 4" wide at the throat.

If you're going to go ahead and build this modified Rumford, build up the three or four rows at the bottom and on the side walls.  At that point, use the angle guide for the side angle and set your level, using it as a straightedge, to the back of the damper frame.  We don't use a standard damper frame either, we use a top-mounted system.

After both marks are made on the sidewall bricks, you'll have to shim as needed on your saw to make the single compound cut.

See http://www.bia.org/pdfs/RumfordFireplace.pdf for details.  The additions I would make to this would be:  

1.  On drawing 2, parge the breast smooth, like a side view of an airplane wing.
2.  Use ROUND flue tiles or a round stainless steel lining system insulated with a pour-in insulation.

Thanks for using AllExperts.Com and good luck with your project.

Sincerely,
A. Bart Ogden, President
Home Safe Hearth & Chimney
Wichita, KS
Voice: 316-265-9828
Fax: 316-265-9890
www.homesafeks.com

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Bart Ogden

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I can answer questions related to chimney and fireplace cleaning, construction and repair as well as questions related to the performance of chimneys and fireplaces. I can also answer questions related to clothes dryer vent cleaning and repair. Additionally, I can field questions related to masonry repair.

Experience


Experience in the area:
28 years experience in the chimney service/installation/repair field
President, Home Safe Hearth & Chimney, Inc. Wichita, Kansas

Professional Organizations:
Member, National Chimney Sweep Guild (NCSG)
Member, Hearth, Patio & Barbecue Association (HPBA)
Member, Kansas Guild of Professional Chimney Sweeps (KGPCS)
Member, Midwest Chimney Safety Council (MCSC)
Member, Kansas Association of Real Estate Inspectors (KAREI)
Past At-Large Director of the National Chimney Sweep Guild
Past At-Large Director of the Chimney Safety Institute of America
Past Secretary, National Chimney Sweep Guild
Past Secretary, Chimney Safety Institute of America
Member, National Chimney Sweep Guild Technical Advisory Council
Member, Chimney Safety Institute of America Certification Committee
Past Chairman, CSIA Chimney Safety Education Brochures Committee
Past Chairman, NCSG Nomination Committee

Publications:
SWEEPING Magazine, The Journal of Chimney & Venting Technoloty, A Publication of the National Chimney Sweep Guild
SNEWS, The Chimney Sweep News
THE KANSAS SWEEP, The Voice of the KS Guild of Professional Chimney Sweeps

Education/Credentials:
BA, Wichita State University
C.S.I.A. Certified Chimney Sweep
C.S.I.A. Certified Dryer Exhaust Technician
N.F.I. Woodburning Specialist
N.F.I. Gas Specialist
Chimney Diagnosis & Documentation Seminar
Ahren's Masonry Restoration School Graduate
Advanced Gas Certification
Master Gas Certification
Licensed Mechanical Contractor
Pellet Appliance Specialist
Venting Design Specialist
Dale Carnegie Course Graduate

Awards and Honors:
Superior Dealer Award, Ventinox Chimney Lining Systems

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