CMU Base Size

[Blairt]

I've been looking at the photos in the FB build manual and I'm confused as to the size of base required. For a 42" oven, it states that the base should be 65"x78" but in the photos, I'm seeing bases that are both 4.5 CMU blocks deep and 5.5CMU blocks deep. Which is correct?

[MarkJerling]

I've been looking at the photos in the FB build manual and I'm confused as to the size of base required. For a 42" oven, it states that the base should be 65"x78" but in the photos, I'm seeing bases that are both 4.5 CMU blocks deep and 5.5CMU blocks deep. Which is correct?

65"x78" is a good size. I based my 42" oven on that and went fractionally larger at 2014mm x 1690mm. That has worked well and have provided me with enough size for my (very thick) insulation layers.

[Blairt]

Thanks Mark! That will make things much easier for me!

[UtahBeehiver]

The FB plans do have a few inconsistent dimensions that have been there from day one. It is best you sketch or in you are computer literate use Sketch-up to lay your project out. I did a 42" corner build and when completed the finished edge was at the edge of the hearth base. It is better to have more than less.

[Blairt]

Thanks Russell. Your photos are fantastic! I plan on using mortar on my CMUs rather than just dry stacking. I'll still fill with concrete but I feel that the mortar will just add more strength which can't be a bad thing - can it? I have room to be a full 5 blocks long but not 5.5 so with mortar I should have good space for the oven and a landing out front.

[UtahBeehiver]

Look at Gulf's build, he has quite a tall chimney.