In Progress with a Plan

[From_IT_to_PIZZA]

Hello Everyone, newbie here from Chicago.

First time building anything like this so I am sure I have a lot wrong here.... Any feedback or guidance on what I need to change would be very appreciated >

Area
I already have my cinder-block outdoor kitchen parameter built.

Base
Using cement board (sitting on Rebar) as my starting point for the 4inch base slab with a 1 part Portland cement \ 5 parts perlite \ 2 part water mix with Rebar and mesh. Should I be using glass bottles in the slab?

Fire Bricks
Will put about 1 inches of sand to help level the area and place Rutland brand Fire Bricks to cover the entire area of the base. Any specific type of sand or should i just use Refractory cement as my mortar to attach the firebricks to the base?

Dome
I know this may not be a favorite but I am set on using the Doghouse as my template for the dome. Appy plastic wrap to the template and use Rutland refractory cement mixed with refractory stainless steel needles (Ebay link from this forum) and my first layer with a thickness of about 2 inches.

Chimney opening will be 6inches.

Will get a wet moist blanket or large towel and place it on top of the dome for about 5 days under a tarp as it cures.

After 5 days I will remove the blanket and carefully lift the dome off of the doghouse and place it on top of the Firebricks on its permanent location.

Next will wrap the dome with the 2inch fiberglass blanket with chicken wire to keep it in place.

Next add a layer of 1 part Portland cement \ 5 parts perlite as an additional layer of about 1-2 inches. Or should I just use the same mix as my first layer with refractory cement and refractory needles? Unsure if I should use Stucco as my final last layer or not.... may end up using thin bricks cut in half for a decorative feature.

repeat the process with the wet moist blanket or large towel and place it on top of the dome for about 5 days under a tarp for it to cures.

Will probably get regular (not fire) half bricks with refractory cement to make an archway for the front.

One thing I would like is a way to add 2 hooks on the inside of the oven with the ability to connect a string or maybe even a rebar allow for hanging food items. I am sure I will need to make sure this is planned prior to my first layer of cement.

I dont know what else I am missing or what else I can do \ change to make this better as I do hope to use this long term.

[From_IT_to_PIZZA]

Here are some pics of my cinder block perimeter so far.

[rsandler]

I'm a little unclear on the details of some of what you're proposing, but from what I can follow I see some issues. I would highly recommend you download the free Pompeii plans from this site and read them thoroughly before proceeding. Even if you ultimately make a cast oven rather than a brick oven, you'll have a better sense of what is required to support and insulate a wood-fire oven.

Others can probably give you an informed opinion on your casting plans, but some big things that leap out to me:

- What you're calling a base layer will not support the weight of an oven--you need standard concrete, with sufficient rebar, for that. Perl-crete has very little structural strength, rather it serves as insulation. Putting rebar in perlcrete won't make it much stiffer and undermines the insulation function.
- You may just be using the wrong term for the right material, but under no circumstances should you use fiberglass insulation on a WFO--it will burn or melt at the temps the top of the dome gets to. Ceramic fiber blanket is the usual material used.
- For perl-crete on the *top* of an oven, 5:1 perlite:cement is richer than necessary (too much cement, too little insulation); folks who know around here usually recommend 10:1 on top.
- Not sure how big of an oven you had planned, but just based on the number of blocks in your picture, your cinderblock structure doesn't seem deep enough unless you have quite a small oven planned (the successive layers of wall, insulation and stucco add up, plus you need more room in the front for chimney than you need on the sides.

[From_IT_to_PIZZA]

Thanks for the response rsandler .

- Understood, so no perlite for the "Base" and just use 4" of standard concrete with rebar.

- Yes you are correct, my terms are off and it is Ceramic Fiber blanket.

- For the perl-crete 10:1, this would be my very top and last layer on top of the chicken wire? Or do some use this in layered approach?

- The inside of the oven should be about 42" in diameter, and I plan to have the oven on a 45 degree angled with the opening towards the rest of the kitchen. But I think you are right and I may need to add an additional block or have the 4" thick cement base with a bigger lip.

[UtahBeehiver]

Plus one on reviewing the eplans from Forno Bravo, although dated the info is a great baseline for design and construction of a WFO.

[From_IT_to_PIZZA]

Thanks UtahBeehiver Been reviewing it all day....

I can see the changes I need to make with pouring the concrete hearth and then either install FB Board or pour a second layer of insulating concrete or perl-crete before the firebricks can be laid out without any adhesive. The instruction say to to make an underfloor paste, mix 1 part of fine sand with 1 part fireclay, then add water until you reach the texture of a sticky mortar (but without the cement).

I may need to downsize the oven too, reading on the forum it may appear the 42' maybe too large.....

[UtahBeehiver]

I have a 42" and it is a monster party oven. It is great for doing large groups but we find that for the two of us it is not worth really effective for firing up for just us. Smaller ovens heat up faster, use less fuel and can multi-day cook just as well as a large oven. The key is insulation both under the floor and dome as well as over the dome surface. Where is Chicago, the boss is from the NW berbs.

[From_IT_to_PIZZA]

We have a large family and we do get together often for meals, but I cant imagine making more then 2-3 pizzas at the same time, and they should cook quickly.... I need to reassess and make the size adjustment as necessary.

I should have the blocks done this weekend so I should have a good idea on what needs to be done.

NW Burbs are nice, I'm in the city on the north side.....

[UtahBeehiver]

pcrete/vcrete is a suitable insulation attached is information showing the K (thermal conductivity - lower better). 5 to 1 under the floor and dome edge and 8-10 to 1 over the dome.

[rsandler]

As far as laying floor bricks, although the plans recommend sand and clay mixed with water to make a paste, experienced builders on here recommend just using dry sand/clay. In practice the insulation has a tendency to suck all the water out of the paste, and then you have wet insulation and unworkable paste. In either case it's really just for levelling, not securing the bricks (the weight of the oven will do that). If your insulation layer is acceptably flat/level, you can just lay the bricks directly on the insulation (I skipped the sand/clay mix on my first oven because I couldn't make it workable, and on my second oven just used dry sand/clay in a couple places where the bricks were wobbly).

[From_IT_to_PIZZA]

Perfect! Just dry sand for leveling purposes it will be.

I will post more pics after the weekend with my progress.

[david s]

It is better IMO to keep the mix dry in order to allow movement of the flooor bricks as they expand and contract. It also makes removal easier should a brick need replacing. A wet sand and clay mix will set hard and impede brick movement as well as making pulling up a cracked brick much harder.



For my ovens I solved the uneven floor brick issue by creating a two piece cast, casting upside down which creates a perfectly flat surface, employing a single tongue and groove join. This then provides two manageable sections with the single join providing sufficient movement for expansion.

[JRPizza]

Lots of builders have had success with sorting their floor bricks for uniform height and not using any leveling compound, provided they are going on a flat level surface. That is what I did - after sorting I easily had enough bricks that matched to get a nice flat cooking floor.

[UtahBeehiver]

As constructions starts I will move your posts to the "build section". Let me know what you want to call it or you can start in thread in this build section and I can move all the previous posts over to the new one and thank you for not starting a new thread for each question. It just keeps the blog more streamlined.

[UtahBeehiver]

Even if there are some minor high spots (peel catchers) you can knock the edges down with a diamond cup grinder on an angle grinder once the floor is laid. Some builders have had some success using a belt sander as well. But an angle grinder with a diamond cup will come in hand with the dome and arch construction. Nothing fancy and you can get at HF pretty cheap.