39" (100cm) Pompei Oven Build in Belgium

[GreenViews]

Wow! most excellent. I'm getting more excited as my oven nears the ready stage! Thanks for sharing pics of your first pizza night!

[Kvanbael]

Back to building... the granite top arrived. It was cut in one piece which was an unnecessary risk, if you ask me. But anyways, it looks great, and my brother in law got a round tabletop from the 'leftovers'.

I had to unbolt the vent for placing the granite, so I took the opportunity to insulate the front with CalSil and (somewhat) waterproof the floor insulation with aluminum foil and regular silicone (I first used a grey high-heat kit, but that one turned out to be not waterproof)

After mounting the vent back, I could finally start building the vcrete layer. As yet another weatherproofing, I hid a layer of rubber paint inside the vcrete base (see picture).

I find this vermiculite concrete quite challenging to work with. I started with 6:1 mix ratio, but got very weak and brittle results (even after 3 days of curing). It is also hard to 'feel' the right amount of water. For the second row I switched to a 5:1 ratio, a bit more water and a bit more compression. I hope this layer will be stronger. I was planning to do a mosaic finish, but now I feel like I will need some kind of stucco/rendering layer in between, just for strength.

So here come my questions:

• Is it normal that the vcrete is so crumbly? Should I redo the weakest parts?
• Any European stucco-material recommendations for strengthening the vcrete before applying a mosaic tiling?

[david s]

The more cement you add to the vermicrete the less insulating it becomes. However, if you have plenty of blanket layer this won’t be too much of a consideration. The stuff needs to be mixed in the correct ratio for water addition. Too little water leaves it crumbly and not too workable. Too much and the cement is washed off the grains. I find the correct amount is 3 parts water for every 10 parts vermiculite by volume. Mix the cement dry with the vermiculite first and add 1/3 water, mix well, then add the second 1/3 mix well knocking down any lumps with the back of your spade then the last 1/3 and mix well. I use medium grade vermiculite but if it’s fine you may need a little more water. A handful of powdered clay for every litre of cement added helps to make it more workable. Mix in a barrow not a mixer.

[Kvanbael]

Latest update from Belgium.

I finished the vcrete and let it cure for a week, then did 2 more curing fires.
I also made a door with a stainless steel front, 3/4 inch plywood, "protected" with some tinfoil and a fireproof rope seal.

Today I decided to test her limits. So I fired her up until the entire dome was clear from soot (there was a lot of soot from all the curing fires at low temperature with poor quality timber. I am using clean and dry oak now). By the time we started diminishing the fire, the apex measured around 1000 F and the floor 800 F. When the fire had reduced to mostly embers, we grilled vegetables for a lasagna on an improvised tuscan grill. Then it was time to take out the fire and prep the oven for bread baking. As it was still too hot, we left it open for almost an hour. Then we baked our first 4 loafs (floor was 500 F by then).

After we came back from our Sunday walk, 5 hours after removing the fire, we still had a solid 425 F, which we used for baking some brioche. I'm really happy with the thermal curve of the oven (I have 2inch or blanket + 3inch of vcrete). We will bake a lot more bread and learn as we go. Later I'll collect some more measurements to model the temperature curve.


In the meantime, still uncertain on what materials to use for rendering the dome. We want a pebble stone mosaic finish. Hoping to get some professional advice, until then this is what I am considering:

Omnibind TPW waterproof Primer
Omnimix 90GR to level the dome
Omnicem PL85 to glue the mosaics
Omnifill 142 to grout

[UtahBeehiver]

Nice looking breads

[jonasm]

Hi Kvanbael,

Very nice oven so far!! I also live in Belgium and thinking about building my own oven in my garden.

Where did you get all the materials from? Any advice of good shops is more than welcome.

Also, where did you buy the vent?

Good luck with your project

[Kvanbael]

Hey Jonas. I sent you my email in a personal message.
bought most my stuff on broodroven.com

[Kvanbael]

Been a while since a posted an update, too busy baking pizza and bread, among other things.

Last month we hit a big milestone in the build: We are now waterproof! No more improvised tents and tarps (well, in the winter maybe).

I installed 3 simple steam vents across the dome. Made from standard brass and coper plumbing parts. I used the same copper tube to drill through the vcrete layer. Before firing up the oven, I just unscrew the bolts. Haven't noticed any steam or pressure but better safe than sorry.
Next I treated the dome as if installing a tiled outdoor shower: First a primer to reduce the vcrete absorption, then a flexible water barrier (like RedGuard), finally sealed the edge to the stainless steel front with a flexible high-temp (600F) silicone.

I have started laying mosaic tiles. It's a slow but relaxing job. I have another pizza party on the 25th, would be nice to have the dome completely finished by then.

To end this post, a picture from our latest bread-baking sessions. 3 batches in total, the first batch was a sourdough at 500F which came out particularly nice. My wife made a plead to never bake sourdough in the regular oven again.

[UtahBeehiver]

Nice looking bread.

[CapePizza]

Really nice looking bread, Kvanbael. My wife bakes bread of all sorts twice a week. Nothing like fresh baked bread. Those other baked goods you posted look pretty tasty too.

[Marzano San]

Interesting stuff the steam vents, I have to look into this.
BTW great looking oven too!

[mongota]

I like the stainless vent as a stand-alone piece. Very nice.

The granite? WOW! Congrats on that getting installed without snapping. I would have been worries as well.

Your bakery simply looks divine. Next time I fly to Brussels...lol

[Kvanbael]

Autumn kicked in and weather has been awful. But in between the days of rain, we completed the mosaic puzzle, got it grouted and silicone sealed. And so, this afternoon, about 200 days after putting the first shovel in the ground, ...

our build is complete.

(OK, the base still needs a stucco, but we'll leave that to a pro. Our building work is done).

Thank you to the moderators, and everybody here on the forum. Among various online and paper sources, this forum stood out by far. The build instruction PDF is information-packed, the other member's build threads are inspiring and motivating, not to mention the words of encouragement and advice I got for my own build. I even made some friends along the way.

This is not a good-bye. I will probably post some food results, or maybe maintenance questions.

See you around.

[UtahBeehiver]

Congrats on finishing your oven. Now a different type of fun and adventure starts and you get to experience how versatile a WFO can be.

[CapePizza]

The tile work you completed on the outside of your oven looks really very nice, Kvanbael. Congratulations on your completion. Use your oven well. I'll look forward to seeing more of those beautiful breads you once had shown. And thank you for your comments you had shared along the way and the helpful suggestions you offered. BTW, that is one beautiful setting where you're located. Enjoy your oven!