Looking for affirmation!

[lventi]

Wow - you are all super helpful! Thank you very much; I really appreciate your time and knowledge-sharing! Yesterday we finished the floor of the oven, but i'm worried. We compensated for some of the lower edges by building up the sand/fire clay paste. But b/c there's nothing in that paste but sand and clay, won't any rain just wash it away and there we are with shifted bricks? Or should we just cover it and the weight of the eventual oven keep everything in place? Maybe we should add some vermicrete along the outside edges of the brick to seal in the sand? (I'd attach a pic but can't seem to upload it.)

[UtahBeehiver]

Pictures greater than about 1.1 meg are too large to attached, you need to resize. Unless you have direct and forceful exposure of the fire clay/sand it should be fine. I take it the bricks are not uniform thickness. Any high edges can be smooth out with an angle grinder or belt sander. High edges will catch the peels.

[lventi]

Hmmm ok...just seems weird to potentially have "standing water" that might eat away at the edges of the sand, given the amount of rain we have in Oregon.

[lventi]

Especially worried because we literally used the sand layer to build up the edges of the floor. But, if we mortar or cement around the edges of the floor, then the cracks between exposed bricks (the edges) will let in water but the sealed edges will make it harder to escape.

[lventi]

The bricks ARE uniform thickness and it's pretty darn smooth though not 100% perfect. We'll assess and smooth with a sander if needed, but the floor that'll be exposed (not covered by vermicrete) is pretty smooth. Thank you! It's the sand and the potential wearing away of that base that has me worried....

[UtahBeehiver]

I guess I misunderstood your comment on uniform size, you said you had low spots needing to adjust by fire clay sand. Do what you feel you need to do on sealing the ends. That said, there are dozens of pacific NW builds that have not reported any settling or eroding of the fire clay and sand. The most common problem with exposed ovens in wet insulation, without an egress point the water will just set there and definitely affects the floor temp.

[lventi]

Oh that makes sense. Thank you. I think we'll keep it fully covered until it's complete with stucco, waterproofing, etc. Then maybe seal the edges as well as any spaces between bricks that would allow any water intrusion at all. One step at a time...for now, we still have a dome and vent to build! THanks much,
linda

[lventi]

Hmmm well the "dome" is finished...not beautiful by any means, but it is finished. Thank you David, Mongo, and JR!!! We did our best to build as well as possible (ala Mongo's advice), but when we reached the level where the vent and dome attach - well, that was the beginning of the ugliness. We had a few frustrating days where the progress was super slow due to odd-shaped turns and crannies. The result is pretty much a dome but with an ugly pathway up the front where the bulk of the patches took place, since we plan to use 6" of vermicrete as insulation anyway. It won't look great on the inside either though. While we would have preferred a pretty interior, we're all about the food in the end. So here are the questions:
- We're almost out of Heatstop. Where the bricks have been sort of crammed together at weird angles and not necessarily coming together at the seams, should we fill with Heatstop (ie buy a new bag)? Everywhere is sealed as in all nooks are filled and you can't see daylight, but a brick may stick out an inch further in one area. Or the Heatstop is somewhat crammed between two bricks but it's not smooth on the inside...should we fill all of that in? Will heat escape if we don't fill it in on the inside? Would we be smart to fill all interior jagged edges and/or smear a coat all around the exterior before the next step?
- We plan to let it dry for a week or so, then cover with vermicrete 8:1 in layers, waiting a week in between until we reach 6". Then we'd begin the curing fires.
***Now that we've attempted to make a beautiful oven (and can see the resulting oven that will hopefully cook well but certainly isn't a beaut), I have serious appreciation for those of you who 1. built an oven, 2. give back via this forum, and 3. somehow built ovens that look AMAZING!

[shanxk8]

Hi Iventi, i filled the outer gaps & crannies you described at the vent/dome intersection with a homebrew mortar. Where the gap was very large, i took or cut a scrap of brick to fill in some of the space so I didn't have to use so much homebrew mortar.

For the gaps i'd left on the inside of the dome, i'd tried to fill those with a bit of my remaining heat stop. I forgot to wipe the excess with my wet sponge, so am left with some ugly mortar at those joints instead of nice bricks. If the dome is fully enclosed & not letting in daylight, i'm not sure there is need to fill the inside gaps. Perhaps Russell or Joe could chime in to confirm about this.

With all that said, the only time i'm looking inside at the inside of the dome now is to make sure the dome has cleared & getting ready to cook pizza. I could care less what the inside looks like now, just how the pizza (or other food tastes).
Now I'm still slowly progressing to finish my exterior, & hoping i can keep it moving enough to get it waterproofed before the cold & snow arrive in a few months.

David

[UtahBeehiver]

You may be able to tuck and point some of the large gaps in the interior but for the most part builders say it falls out eventually. I second, using some home brew to fill in the gaps on the outside of the dome. Heat Stop does not recommend joint sizes bigger than 1/2" anyway. Most people will not stick there head in the oven to inspect you work anyway, there more interested in what comes out of the oven. On curing, this is the point where we see builders lose patience and cure their oven too fast and hot, cracking their ovens or render. Take your time, you can cook some things during the curing phase.

[lventi]

Ew...based on the 3/8" rec, we may have some issues in the future. Our outside joints are often 1/2" and even more...inside joints are where we tried to focus on having brick against brick so they should be pretty small for the most part. (Haven't removed our cardboard mold to see what it looks like!) There shouldn't be any light coming through - we've mortared each joint pretty heavily - between bricks and on the outside to fill. More questions generated:
- Could/should we put a layer of Heatstop all around the outside (one more $135 bag!), even though we've mortared pretty heavily and no light can be seen?
- Or should we put "regular" mortar all around the outside?
- Or should we just let it cure for a week and then carry on with the vermicrete up to 6"?
- Is this correct: let it dry/cure for a week, then we can start the low fires?
- Do we vermicrete BEFORE the low fires, after, or ok to do both at the same time?

[shanxk8]

+1 for cooking during the curing fires. We did a beef roast & chicken legs during curing fires and they turned out exceptional.

I don't think you need to buy more heatstop to put around the outside. Regarding this, are you wanting to cover the bricks, or just fill remaining gaps between bricks?
The 1st picture I included is what my dome looks like under the CFB I installed. The 2nd picture I included shows the size of gaps between the bricks that I was filling with homebrew mortar.

As Russell said, waiting 1 or 2 weeks to cure is important (i think i ended up waiting three, as i insulated and then had other commitments prevent me from doing oven stuff).

[UtahBeehiver]

Sequence before curing, Fill outside joints with Home Brew, insulate - in your case vcrete in layers or lifts, let DRY for several weeks, then SLOW cure - refer to Forno Bravo curing schedule on their website, then add final stucco or render coat. Recommend a vent relief at apex of dome.

[lventi]

THANK YOU!!! We've filled all of the outside joints with Heatstop. Still not seen the inside joints...but there's at least SOME Heatstop in every gap as the outside is covered and there's some significant Heatstop between each brick (just maybe not all the way through to the inside seam). So now will let dry for a week or so, then do the 6" of insulation, then wait for a month (plus) as you advise before the firing/curing and THEN the stucco layers. Never heard of the vent relief - will read about that. we DO have our 8" chimney at the beginning of the vent/outside of the dome.

[shanxk8]

Here is the discussion i was pointed to in regards to adding a vent when completing the dome with stucco (or tile). I've yet to stucco, so still need to source a breather vent for this application. (hopefully soon)

https://community.fornobravo.com/for...omments-please