First course of brick upright or flat pros and cons

[davdebj]

The FB plans discuss putting first course half brick upright and also an option to put it flat. My firebrick is 2.1" x 4" x 9" Whitacre Greer. If I put the first course upright it will be 4" which causes an issue because 2 flat bricks will be 4.2" and I think that will cause issues with my oven opening lining up with the dome. Can someone explain why it seems most people are putting the first course half brick upright? Thanks.

[UtahBeehiver]

Are you enclosing the oven or not? The FB plans are a good baseline but many improvements have been developed by the forum members since the original eplan publication. I am not sure that most people are putting the first course with what you describe as half brick uprights. See the attached pic. More likely it is a half header.

[davdebj]

I plan to make igloo if dome turns out okay. If it is a mess I will box it in. The image below is what I'm planning, Of course though I will align the bricks so the joints are more offset from course to course than shown in the image. Dave

[UtahBeehiver]

Couple items since I have a visual now, the design is using half headers rather than half soldiers or rowlock. This is the more common starting point. You have two options for the floor, Cut to fit inside of dome or dome sits on top of floor, the former takes more cutting to fit but allows removal of floor brick if necessary (however, I have only seen one or two out of hundreds that required a brick removal). The later requires less work by rough cutting the floor bricks and leaving proud, IMHO, I would do this method if I were to build another. Based of the CAD drawing, if to scale, the insulation under the floor and dome does not appear adequate, You need a bare min. of 2" of CaSi or AiSi board or 4" of 5 to 1 p or vcete.

[davdebj]

Thank you for the info. Off your cut bricks. Dave

[davdebj]

Off TO cut bricks.