Oven Entry question

[Jim Bob]

In process of laying out where the oven floor will lay on the new insulated slab. Maybe the FB specs tell us somewhere how long the entryway into the oven should be, but unable to locate it. I am doing the high dome Tuscan oven with an arched entryway and have created an 8" cantilevered ledge on front edge of the vermiculite/concrete slab. The length of this entryway may not be real critical, but would still like to know the preferred length.
Appreciate any help,

Jim Bob

[Jed]

Morning Jim Bob,

I ended up with 14 inches.

This dimension seams to work well for all function. Not so deep that I can't tend the fire, deep enough that there was sufficient room for a good size vent that draws well...

JED

[Jim Bob]

Jed,
Thanks very much. I noticed that the ledge level is even with the entryway firebrick. Did you raise the level of the insulated layer of vermiculite/concrete up to the firebricks? Just wondered how it bonded with that insulated layer if you did.

Jim Bob

[Jed]

Hi Jim Bob,

The fire brick oven floor (and entry) and the front counter top both sit on the perlcrete insulation layer. These two pictures show a before and after.

The counter top is colored poured concrete, so I installed enough of this to come up level with the fire brick floor.

JED

[Jim Bob]

I see what you are talking about on the colored concrete. it looks good. So, when dry did you take up the 2x4 boards on the edge? That still leaves 3.5" of the insulated layer exposed below that on the edge. It seems to me as I watch this insulated layer cure that it is very unstable and will crumble or chip off at the slightest hit with any kind of tool. What am I missing here?
Thanks for your patience,
Jim Bob

[SpringJim]

Originally Posted by Jim Bob

In process of laying out where the oven floor will lay on the new insulated slab. Maybe the FB specs tell us somewhere how long the entryway into the oven should be, but unable to locate it. I am doing the high dome Tuscan oven with an arched entryway and have created an 8" cantilevered ledge on front edge of the vermiculite/concrete slab. The length of this entryway may not be real critical, but would still like to know the preferred length.
Appreciate any help,

Jim Bob

I would think that three brick widths would be minimum depth/length....one brick at the oven, one brick for the vent and one brick for the final arch......kind of like Jed's picture too!

I went deeper because I wanted a larger working area in front of the oven.

[Jim Bob]

Jim,
Thanks for the tips. It all helps. I am closing in on getting the oven floor laid and putting in the dome. Also, i keep digging into this forum site for more info. I see why people who have been on this site for years get tired of hearing the same questions. I feel good about my oven plans except for the cantilevered 8" ledge of insulated concrete. It appears very spongy and easy to chip or knock loose with even the slightest wear & tear. So i want to try Jed's answer of using a colored concrete mix on top & bring it up to the level of the firebrick in the entryway. But still worried about the front edges of this ledge wearing off. It needs some kind of cover over it.
Thanks again,
Jim Bob

[dbhansen]

Jim Bob,
Do you have a standard concrete layer that extends under the cantilevered vermiculite/concrete layer? I think most people here who have done a cantilever have used standard concrete for it, with embedded rebar that extends into the cantilever. Then a vermiculite layer or insulation board on top of that. You may be charting new territory if your cantilever is made of vermiculite/concrete only.

[Jim Bob]

No, it does have about 4.5" of standard concrete with the extended rebar as spec'd by FB underneath the 3.5" of verm/conc mix. However, I am still concerned about that exposed cantilevered ledge in that mix section. If i cover the top of it with additional straight concrete, it will be great, but the fron edge of the mix layer will still be exposed between the two layers of concrete. Perhaps I am worrying about nothing important. But as spongy as that layer is, just accidentally stabbing it with a fork or knife or anything hard should cause severe wear on this layer. Does that make sense at all?
By the way i am trying to attach some images with no luck so far.
Jim Bob

[Jim Bob]

I meant to say that i poured 4 full inches of verm/concrete mix on top of the concrete. My mistake.
JB