Premio2G 120 build

[MiScusi]

Currently in the build process for my new oven. Ordered a Premio2G 120 and picked it up at the Forno Bravo factory.

I have the slab done and the block stand is almost ready for the top slab. I'm filling every other core with rebar and concrete. The holes that are not filled with concrete.. what do you guys block those with so that when the slab is poured it doesn't go down the holes? I was thinking about using squares of wood or rigid insulation to block them up.

[MiScusi]

Tough crowd!

Working on the framing for the top slab, plan to pour this weekend. How long do most wait for the top slab to cure before placing any of the oven components on it?

[SableSprings]

A lot of folks have just used the empty concrete bags to fill the alternate block holes, but really anything will work...got some empty plastic jugs? The Styrofoam pieces would do just fine as well or just lay some thin plywood pieces over the holes without rebar. Also I'd strongly advise you to put some weep holes under the oven's future footprint. Before you pour, drill 5 or so 1/2" holes through your bottom form and push pieces of 1/2" plastic pipe up to close to where the top of your poured hearth will be. (Yes, you could drill the weep holes in the green concrete, but if your luck is like mine, you'll hit rebar 4 out of 5 times. ) After the concrete has set, run a drill up the plastic pipe from the bottom. It will pop out a small crater at the surface of your hearth...providing an excellent little well for any excess water that gets in under the oven perimeter to collect and find an exit through the weep hole. A little insect screen material placed over the base of the hole with silicone will keep any bugs from finding a new "home".

Once that top slab (with rebar) has been poured and screed, you'll want to cover it with plastic to keep it from drying out for at least a week but better ten days. At that point it will have achieved pretty much maximum strength and there won't be any problems with the oven's weight.

Before you place your oven's ceramic insulation board on the hearth, we strongly advise to put some broken porcelain tiles on top of the hearth (I like to see the use of 1' ft squares of mosaic tiles used here...flipped upside down so the mesh backing is on top.) The channels between the tiles provide excess water a path to the weep holes and the tiles keep the insulation board from getting wet .)

Here's a link to a nicely documented build that shows the weep hole/tile combo:
https://community.fornobravo.com/for...andpoint-idaho

Hope that helps a bit and welcome to the start of a great friend and family experience.

[MiScusi]

Ok, so I bought some stainless steel straws I am going to use for the weep holes instead of plastic. Should be corrosion resistant and also a little more rigid. For the top vent I bought some 304 stainless pipe with threaded cap that will peek through the stucco. I haven't thought about putting some 1" tiles below the ceramic board but I could do that. It will keep the insulation from sitting in water that might collect on top of the slab. Let me know what you think.

Straws: (for weep holes)


Pipe: (goes in between bulkhead and cap)

Bulkhead: (will screw this down to the stucco mesh)


Cap: (to seal off the stem vent on top when not in use)

[SableSprings]

The straws are a bit more constrictive than some 1/2" diameter pvc so I'd put in more of them if you choose to go that way. The "corrosion resistant and a little more rigid" really is not an issue here since all you're doing is creating a path for water or water vapor to escape if it seeps under the oven...and once the concrete hardens, the tube body is irrelevant. The nice thing about the larger diameter of the pvc option (IMO) is that if it does get clogged, the drill or a piece of metal can quickly/easily clear it out...not so sure about clearing out the much smaller diameter straws.

Do remember that which ever you choose, you'll want to put a piece of tape over the top end so that it doesn't fill/clog with concrete and that you want the top end to be slightly below the final hearth top (so you don't present a blocking lip to water draining out). As I noted before, the straws might be a little more difficult to clear after the concrete has set. The scrap tile/mosaic squares (usually pretty cheap as "left-overs/discontinued patterns" in box stores or at a yard sale") are well worth the minimal effort to install. Do check out that link to the Sandpoint build I inserted in my last post. Also it sounds like you've found the references to the top venting system that's also highly recommended, especially in damp/humid or just plain rainy climates...there are some auto engine venting plugs that don't need to be capped when not in use...

Good luck with your hearth pour this weekend.

[MiScusi]

On the other build you linked... how much benefit is the FoamGlas board he is using? The Premio has 1" extra insulation board on the bottom vs the Casa.

[SableSprings]

The FoamGlas doesn't have quite as high a heat tolerance as the ceramic board, but it's advantage is that it doesn't absorb water. Usually it was put under a layer of ceramic board for that reason. Some of the newer types of ceramic board resist water uptake and in terms of total insulation, that amount of base insulation of (either kind) is pretty much equivalent...you'll have plenty of heat retention for after pizza cooking & baking! The FoamGlas is more expensive (and difficult to find) and since the weep holes/tiles system really helps reduce the chance of waterlogging, it doesn't really seem to be an issue like it used to be. I don't know if the bottom layer of your Premio is the water resistant type or not...in either case, I still like to see that ceramic tile water break between the hearth top and the oven's bottom insulation...cheap insurance/investment/peace of mind for keeping your insulation layer dry!

[MiScusi]

Poured the top slab this weekend. (along with the wood framing, cement board, weep holes, and rebar)
Almost to a point where I can actually put parts of the oven up! (like the insulation and firebrick/tile)