36" WFO in Candia, NH, USA

[MichaelPBoisvert]

My design is based on quite a few of the other builds on here. Here is my progress. Now for the fun part.

[MichaelPBoisvert]

I also used autocad to mock up my plans. I used DeeJayOH's Dome speadsheet to make sure I was getting a decent understanding of the cuts, stacking, and tilt of the bricks.

[Northup]

Posting some answers from your other post. I am located in Rhode Island, maybe 2hours south of you. I ordered 210 bricks at 2$ each. That price included delivery. I got all my insulation supplies in Massachusetts (https://www.smart-ceramics.com/) small place but had really good insulation and other supplies. Oven design looks great have you thought of how you will be enclosing the oven? building a structure around or over the dome to keep the weather off of it?

[MichaelPBoisvert]

Thanks Northup, I believe I am using them for the Calsil. They go by the name rubixcomposites now, but I guess it's the same company.

[MichaelPBoisvert]

Picked up my insulation today at Smart ceramics (Rubix Composite in Woburn, MA). Also picked up my medium duty fire bricks at Hudson Quarry in Hudson NH $1.90 per brick (8.5x4.25x2.25). Going with 4" of calsil and a herringbone hearthfloor pattern that will sit under my dome. I'm pretty overwelmed and nervous, but ready to make some progress. Thanks for all the advice and input. The "what would you different" and newbie threads have been priceless in planning.

[MichaelPBoisvert]

[MichaelPBoisvert]

I was thinking about putting some sort of waterproof in tape around the joint between the calsil board and structural concrete. Has anyone done anything like that? Are there any other options?

[Gulf]

At this stage, I would take the time to unstack, and install a layer of some kind to elevate the insulation up off of the concrete hearth.

EDIT: Concrete pavers are one option.

[MichaelPBoisvert]

Thanks, sounds like a good idea. Would 6 mil poly work? Or would there be a danger of melting even through all that insulation? I'm a little worried about the height if I put another layer of something thick like a paver, but I'll do a little research on thin pavers.

[MichaelPBoisvert]

Or porcelain tile squares?

[Gulf]

The poly will be fine. There won't be enough heat getting through two layers of board insulation to matter. I'm a little leary about advising poly under 1 layer of board strictly because there is a chance that heat could travel directly through a splice. With two layers, the splices are staggered and that is not an issue.

The porclain tiles would probably work just fine for both elevating and as a moisture barrier imo. I would let the tile stick out past the board insulation far enoguh to keep the dome insualtion from touching the concrete as well. If you will be needing something later for which to attach lath, the concrete pavers will work well for that.

[MichaelPBoisvert]

Excellent, thanks for your advice! Raining today, so I was unable to do my first level. After reading a little more I noticed some people have a separation between the dome floor bricks/calsil and the entry floor bricks/calsil. Like a heat transfer barrier, I didn't consider that. Any thoughts/opinions on that?

[UtahBeehiver]

In addition to Gulf's comments, it would be good if you could drill a couple 1/2" weep holes in the hearth under the dome area. This will help and water that finds it way in to migrate out. You can place some wire mesh on the bottom side for a bug guard.

Thermal breaks are a hot topic, you will find opinions across the spectrum. Both Gulf and I installed them, but other builder have not. If you want to eek out every single BTU for 5 day worth of residual heat cooking then it may be helpful but so is a well insulated dome/floor/door etc. So I would say builder choice and anticipated cooking style.

[MichaelPBoisvert]

Thanks again. I like efficiency, so I will delve deeper into this! A thin layer of something non heat transferring, that can withstand heat is the trick, right?

[Gulf]

Michael,

I think that the main thing to consider is that the floor brick not stick out past the insulated door. At that point, I switched from herring bone and crossed the entry. However, I did install a thin layer of ceramic fiber tape there for a spacer. I let the space fill with ash. Here is an old pic from when I was driving the moisture out of the oven. The entry brick are removable and can be turned over or placed back in the oven for a cleaning cycle in the event of a bad stain. I haven't had to do that but once. Dragging some hot coals into the entry takes care of most of that.