Building A Fireplace And Need Some Input

kammerfrank

Hi,
I have built many fireplaces and have been doing masonry all of my life. I am now working on a project that consists a VERY large fireplace. The firebox opening is 12 ft wide and 5 1/2 ft tall and 5 ft deep. Do I have to install a damper or can I just use flue top damper.

stacker

unless you want all the furniture in the room sucked up the chimney,i wouldnt worry about a damper.

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kammerfrank

Hey Stacker,
How far do you think I should roll the back wall in for a smoke shelf, Im starting the back slant at approx 3 1/2 ft high.

kammerfrank

Hey Stacker,
How far do you think I should roll the back wall in for a smoke shelf. I'm starting at about 3 1/2 ft. high.

raskolnikov

kammerfrank,
5 feet deep! Is it a firebox or an elevator shaft? Just curious how large/tall the room is that's housing this monster?

Duane

kammerfrank

2 stories. Event hall with 18 ft ceilings. 300 ft long and 90 ft wide.

jaymasonry

sure would like to see some photos of that

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raskolnikov

Don't get me wrong, I was just thinking asthetics along with it working too. How many times have we all seen these massive fireplaces in a small room where they overpower the space and one finds the flue to be an 8x12 or maybe even a 12x12! And kammerfrank, this is not a dig, I just saw the size of the box and thought...

D.

kammerfrank

I have been racking my brains about flue liners. My thoughts were 2 2x2's but thats too large.

raskolnikov

kammerfrank,
I don't think that's even close to too large! What will the finish height be on this "quaint stack" from the floor of the smoke chamber to the lights for low flying aircraft? Really!

D.

kammerfrank

finished height will be 40 ft.

raskolnikov

IMHO you can get away with 2 2x2 'cept I think you need to pull the depth of the firebox to 30" or mayby 36". Is this supposed to be a working box or just for show??? Show would be better based on what I see from your post.

D.

Tscarborough

Considering the fact that you will need 2 ea 48" dampers and they call for at least a 13x18 flue ea, I would think you will need a double stack of 13x18 flues. The height will help. We lived in a house with a 10'x'5'x 3' deep fireplace and actually burned old RR ties. It was built in the 30's and was double dampered and had 2 separate chimineys. Use this to extrapolate the correct dimensions for your fireplace:

http://vestalmfg.com/PDF/FireplaceThroatDampers.pdf

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jvcstone

To get enough flue area, you could build the flue the old fashioned way with out liners. Double wyth of common brick parged inside and out. Other wise, it will need two conventional flues.

JVC

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kammerfrank

10% of the fireplace opening is 950 sq.". 2 2x2 flue liners give me 882 sq ". I am shy 68 sq.". Do you think it will draw? Any suggestions?

raskolnikov

k.
I wouldn't use smaller than 2x2s and 2 is probably enough with the height you have. Always error in the favor of bigger is better!

D.

Tscarborough

A forty foot stack will suck like Pamela Anderson on a boat.

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raskolnikov

I guess that in ten years or so that fireplace won't suck at all based on that piece of info!

D.

Tscarborough

She is sucking now more than ever.....

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