Outdoor DIY fireplace chimney/smoke issues

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tjsherrill

New Member
May 29, 2022
7
Seattle, WA
I have built a "functional" outdoor fireplace. I am planning on stucco'ing it this summer but before I get there, I have smoke issues.

A few notes:
  • ignore the flagstone
  • I am planning on fire bricking the entire inside
  • From memory the opening is 36X24 and I have a 3' 6" chimney coming out the center back.
When I light this up, it works, and if the wood is dry and burns hot the thing works great, but when starting and early on it dumps smoke out the front.

What can I do to help the chimney work better?

front.jpg chimney openning.jpg chimney.jpg
 

begreen

Mooderator
Staff member
Nov 18, 2005
93,171
South Puget Sound, WA
Is that an 8" stove pipe? If so, it is about 50 sq in a ratio to the fireplace opening of 864 sq in. or about 17:1. It should be more like 10:1. Some additional height would also help.
 

tjsherrill

New Member
May 29, 2022
7
Seattle, WA
Is that an 8" stove pipe? If so, it is about 50 sq in a ratio to the fireplace opening of 864 sq in. or about 17:1. It should be more like 10:1. Some additional height would also help.
So should I go down to a 6" and add a foot or two on top? Should I tape the seams or anything else to set it air tight?

Trying to nail this stuff down before I stucco.
 

begreen

Mooderator
Staff member
Nov 18, 2005
93,171
South Puget Sound, WA
Going down in flue size is the wrong direction. The flue should be roughly 86 sq in area. A 10" or 12" flue would be better together with some additional height.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
28,452
central pa
You also dont have any rise above the lintel. You need to do some research on fireplace design and rework it
 

begreen

Mooderator
Staff member
Nov 18, 2005
93,171
South Puget Sound, WA
As bholler noted, the smoke chamber is also important.
Here are some outdoor fireplace plans for inspiration.
and here are step-by-step plans for building one out of roman stones to compliment the surrounding walls.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
28,452
central pa
Following up on this I had a question: do I need a chimney pipe or could I just use the stone that I have already put in? I could make it taller pretty easily.
You need some sort of suitable liner. Than can be stainless steel clay liners firebrick cast liner etc. But no cement block is not suitable. I also see potential structural issues that looks like thin pavers laid without any running bond. And really no smoke chamber at all.
 

tjsherrill

New Member
May 29, 2022
7
Seattle, WA
You need some sort of suitable liner. Than can be stainless steel clay liners firebrick cast liner etc. But no cement block is not suitable. I also see potential structural issues that looks like thin pavers laid without any running bond. And really no smoke chamber at all.
Ok, fair enough. Having a hard time finding a 12" clay liner. Anywhere I can buy one online and have it shipped?

I'll review the structure. It's not too hard to change now. Can you help me understand what a smoke chamber is?
 

begreen

Mooderator
Staff member
Nov 18, 2005
93,171
South Puget Sound, WA
Yes, and yes, though there are good masonry supply houses that should have 12" clay flue tiles and even that is not really necessary for an outdoor fireplace. The 12" sq. flue could be formed with brick walls too.

For flue tiles, try Salmon Bay in Ballard.
 
Last edited:

xman23

Minister of Fire
Oct 7, 2008
2,440
Lackawaxen PA
Fireplaces need very specific dimension ratio's to draft. I guess you could build a firebox inside of what you have. But if the material is bad maybe starting over is easier. I assume you can buy a firebox and build around it.
 

begreen

Mooderator
Staff member
Nov 18, 2005
93,171
South Puget Sound, WA
Hopefully, the paver fireplace was just a prototype for practice and a better design will follow.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
28,452
central pa
Fireplaces need very specific dimension ratio's to draft. I guess you could build a firebox inside of what you have. But if the material is bad maybe starting over is easier. I assume you can buy a firebox and build around it.
The material of the base and firebox structure looks ok. But it needs a proper smoke chamber built and then a chimney that is structurally sound
 

begreen

Mooderator
Staff member
Nov 18, 2005
93,171
South Puget Sound, WA
The material of the base and firebox structure looks ok. But it needs a proper smoke chamber built and then a chimney that is structurally sound
Will the paver interior wall crack and spall quickly? I was thinking it should have a firebrick layer for the actual firebox.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
28,452
central pa
Will the paver interior wall crack and spall quickly? I was thinking it should have a firebrick layer for the actual firebox.
Yes it needs an actual firebox inside that structure made of firebrick