Finish top of base with regular brick

Mattone Barile & Mattone Barile Grande Ovens
1

Two questions:

  1. Wanting to place 4x8” regular clay bricks ¾” over the edge of the Mattone barile slab to create an overhang (rather than to edge of the slab). Want to do this to protect decorative clay tiles to be thin-set to side of concrete slab underneath the brick overhang. Of course fire brick would go out ¾” further on each side.
    My question is does this create an insulation problem, as it goes ¾” further out from the vermiculite/portand cement insulation in the middle of the pad? If it is a problem, as a follow-up to my first question could I put a layer of ceramic board out to the edge of the brick? To then cover it with a thinner layer of sand and then firebrick for the floor of the oven? Does this bring up another question, can the board withstand the weight of the sand and firebrick, and not get compressed overtime? Particularly by the weight of the dome. Alternatively, a more expensive option might be to add insulation using 1.25 inch vermiculite insulating bricks (the kind used to line stoves), then all-purpose sand for leveling and then firebrick.

  2. Is the washed mason sand that comes in the huge hundreds of pounds bags for commercial purposes the same as silica sand used for making up the high-temp mortar? My contractor is building out the surrounding stone patio has a lot of it. And if mason sand is not pure enough, would it even matter if it was used in the high-temp mortar recipe for the brick install, as it seemed in the base instructions (but not the oven instructions), that regular mortar could be used for the brick border? Of course I’d still use pool sand for the firebrick (now about $25 a bag)! Also, the contractor’s mason sand is a lot finer than the pool sand.

Thanks, sorry for the long read!

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Hi Mike and welcome to the Brickwood forum!

Short answer for your first question: no, doing this as you suggest will not create an insulation problem. The insulation in the slab is there to keep heat from conducting through the hearth and being sucked down by the concrete underneath. Once you get under the arch, the hearth is no longer exposed to direct flame. (In fact, the hearth on all of the ovens extends under the arch.). In that space, heat will be absorbed by firebrick and tend to refract back into the oven.

So you should be fine on that score.

And on the second question, I don’t see any issue with using washed masonry sand in your high temp mortar mix. Although it has many uses in landscaping and even gardening, mortar is its many reason for being. “Washed” means that it has been sifted and cleared of stones and various contaminants, and it will compact very well—which is a desirable quality for mortar.

Hope this helps!

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All I’d hoped for. I did the base myself, but leaving the brick to a mason. And thank you for your timely response he is laying the brick as evenly as possible on Tuesday. I’m doing the rest myself—excited to get started on the oven!

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