What material to use for top (roof) of brick firebox?

[nestorint]

Hello dear members.
As I am in the process of building brick smoker I am not 100% sure what material to use for top (roof) of brick firebox?
I thought if to put sheet of steel (about 4-5 mm thick) and than bricks on the top. But bricks and steel expanding and contracting at different level under heat.
So with time it may not only build cracks on bricks on the top but also could start break the walls of firebox.
What do you use ? Thank you

 

[nestorint]

View attachment 686726

 

[smokerjim]

I built one 20 some years ago, I can't remember how thick the steel plate I use is but it's also reinforced with angle iron which you can't see in picture. I think it would warp without them.

 

[HalfSmoked]

Poured Concrete would be a good choice.

Warren

 

[seenred]

If the "roof" is an access point to either chamber, I'd go with a hinged steel plate of at least 1/4" thick - reinforced as smokerjim mentioned. If these roofs do not provide access, you could make them out of the same bricks you're building the side with, or poured concrete as HalfSmoked mentioned.

Your progress looks great!

Red

 

[nestorint]

If the "roof" is an access point to either chamber, I'd go with a hinged steel plate of at least 1/4" thick - reinforced as smokerjim mentioned. If these roofs do not provide access, you could make them out of the same bricks you're building the side with, or poured concrete as HalfSmoked mentioned.

Your progress looks great!

Red

Thank you for compliment. But I thought the top of the firebox is where highest temperature would be and concrete would crack. If it's recommended to use firebricks at the bottom and side of the firebox to prevent fire touching regular bricks at the sidewalls of firebox but just concrete at the top...

 

[seenred]

Thank you for compliment. But I thought the top of the firebox is where highest temperature would be and concrete would crack. If it's recommended to use firebricks at the bottom and side of the firebox to prevent fire touching regular bricks at the sidewalls of firebox but just concrete at the top...

I suspect you are correct, if you use regular concrete. I'm certainly no masonry expert, but they do make a high-heat cement mix. A quick google search produced this result:

Portland Cement - High Temperature Mortar Ingredient

Portland Cement is the glue that binds your High Temperature Mortar blend together! Portland Cement - Delivered to your door!

www.brickwoodovens.com

You mentioned firebricks - is it possible to construct your roof out of firebricks? Just something else to ponder.

And if you're concerned about the effects of heat on stone or cement products, I'd definitely go with a steel plate - perhaps even an insulated plate: double walled with and air gap or insulation in the middle.

Red