# Outdoor fireplace question



## Geiri (Oct 28, 2012)

I was recently asked to build an outdoor fireplace using concrete blocks. 

The fire chamber will be 3x3x3 feet and then a chimney 


My question is dose an outdoor fireplace need a smoke shelf and a throat like shown in image F-11?? Will it help? 

Or should I just go with a simple design like F-12?

What are the most common mistakes in building outdoor fireplaces? 

All advices welcome


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## bytor (Jan 23, 2010)

What type of firebrick firebox are you building? Traditional sloped back or straight back Rumford-esque? Either way, firebox will create a smoke shelf of its own, just a different configuration.


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## Rockmonster (Nov 15, 2007)

3 feet deep? I'm looking at the drawing, I guess so......hmmm........seems more oven than fireplace.....


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## Geiri (Oct 28, 2012)

Thank you for your replay's 

The fireplace I have constructed is 33" by 33" square with straight back. I was just wondering if I would get a better draft through it if I created a throat and a smoke shelf.. and maybe a better burn

Do outdoor fireplaces suffer from down rafts and do they make good use of throats and smoke shelfs? 

Geiri


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## brickhook (May 8, 2012)

When i build outside fireplaces, I like to put fire boxes in with sloped backs to help reflect the heat towards the front of the fireplace. I also put smoke chambers and throats in aswell. I put dampers in, so after you finish using the fireplace you can close the damper, and if it rains, it won't wash the ashes out on the hearth or patio. As far as an outside fireplace drawing, you can't control the eliments outside, as far as down drafts, up drafts, and breezes. I think if it does'nt draw perfectly, it wouldn't be noticed. Good luck.


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## Tscarborough (Feb 25, 2006)

It doesn't matter if it is indoors or outdoors the design is the same, with the damper optional on an outside fireplace. Personally I would not put a damper in an outdoor fireplace.


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## JBM (Mar 31, 2011)

Geiri said:


> Thank you for your replay's
> 
> The fireplace I have constructed is 33" by 33" square with straight back. I was just wondering if I would get a better draft through it if I created a throat and a smoke shelf.. and maybe a better burn
> 
> ...


What would you do if you didnt create a throat? How would you start the first flue? Or do you mean just have a hollow empty cavity above the firebox? 

What kind of mortar will you use on the firebox and throat?


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## Geiri (Oct 28, 2012)

JBM I have little or no knowledge on fireplaces. :whistling 

I did look up some ideas online

A was thinking of the throat or just a open fire chamber with a straight open up chimney. 

After this discussion I will go with the throat. 

I will be using solid concrete blocks about 7"x10" inces wide to build the fireplace. Is there a problem with that?

Similar to the once in the attached photo but noted on top and bottom. 

Geiri


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## Tscarborough (Feb 25, 2006)

You need to line it with firebrick.


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## Geiri (Oct 28, 2012)

Tscarborough said:


> You need to line it with firebrick.


Do you think the concrete blocks will crack or?


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## brickhook (May 8, 2012)

I don't mean to be pessimistic, but if you have'nt ever done masonry work before, a chimney is not a good place to start. I've seen guys lay brick for years and couldn't build chimneys. If I can help you I will, but I'm just saying. And to answer your question.....the block will crack due to the heat.


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## Tscarborough (Feb 25, 2006)

I don't THINK they will crack, I KNOW they will disintegrate.


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## JBM (Mar 31, 2011)

What was the name of that pre fab chimney thing that was pretty ez to put together? 

Was talked about here oh maybe 6 months ago.


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## Geiri (Oct 28, 2012)

I have been looking into firebrick price it's very high

Any other solutions ? Iron plates? or....


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## Diamond D. (Nov 12, 2009)

JBM said:


> What was the name of that pre fab chimney thing that was pretty ez to put together?
> 
> Was talked about here oh maybe 6 months ago.


Was it this one?
http://firerock.us/products/outdoor-products/

D.


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## Tscarborough (Feb 25, 2006)

Do it right or do it over. Millions of people doing the same thing 
for millennia have pretty much figured it out.


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## jomama (Oct 25, 2008)

Geiri said:


> I have been looking into firebrick price it's very high
> 
> Any other solutions ? Iron plates? or....


None that are going to be any cheaper or easier to work with than firebrick..........


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## Geiri (Oct 28, 2012)

I found a few solutions to day 

First is a cement mixture used in drive through tunnels where accidents can happen and great fires. This can withstand high heat and it can be used to cover the inside of the fireplace. 


Second is this mix

http://translate.google.com/transla...rbruk/murbruk/weber-eldfast-bruk.html&act=url



And third I found tiles thate are burnd at a 1200° heat so they could stand the heat. 


I like the Idea to put tiles inside the Fireplace it will look nice.. 


Any comments on doing some of this??


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## raskolnikov (Mar 10, 2008)

Not very pretty!:whistling

D.


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## stonecutter (May 13, 2010)

Why the resistance to using a proven material like fire brick? It is the most accepted and economical thing to use for a firebox. Going cheap is twice as expensive in the end.


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## stuart45 (Oct 7, 2009)

Can you get firebacks in Iceland?
http://www.youtube.com/watch?v=ZsrhGu58eq8


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## JBM (Mar 31, 2011)

You are building something that just isnt going to work. You have multiple problems, and not the experience to navigate through them. You also dont take advise very well. 

Here are your problems

The chimney is to short
The opening is to big
the flue is probably to small
The fire brick you mentioned are splits
Tile no
Metal, probably not
Are the blocks glued together?
No footing, the firebrick will crack
No footing in general
The trees are overhanging the fireplace
Moisture plus creosote is a problem with exposed cement, hence one of the uses of refractory mortars, clay pipes and fire brick
your throat is probably not built to induce a draft
The size of the flue should be 10% of the opening size.

So to summarize, pour a footing, hire a mason.


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## stonecutter (May 13, 2010)

This thread is making me dizzy but I can' t seem to stop reading it. How many times does the same thing have to be said before it sinks in? This has to be a DIY project.


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