Water protection for super isol

[Alan]

I used super isol board for my hearth insulation and now that my dome is in place I realize that the expansion space between the floor and dome is pretty generous - 1/2 to 3/4 inch all around. The instructions are crystal clear with regard to the fact that this space should not be mortared so that things can move as they heat and cool.

I'm a little concerned about water. I won't have much of a roof overhang and my entry arch only protrudes about 4 1/2 inches in front of the Casa shell. I don't see any indication that the board will be damaged by small amounts of water, but it sure will absorb a lot - it sucks water right out of mortar.

Any suggestions on waterproofing or whatever without compromising the expansion gap? With the door provided, rain could still get between the landing portion of the floor and the dome entryway. Any water that gets in there will need to be evaporated off one way or the other. It just seems like it would be better to have it trapped in the oven chamber than leaking into the insulated space.

[james]

Hi Alan,

The expansion gap is fine, and your description sounds right.

You will want to keep moisture out of the oven -- everything inside the oven will absorb moisture if you give it a chance, including the oven dome and floor, and if it ever got that far, your SuperIsol and even the concrete hearth.

To keep the inside of the oven dry, always put the door back on the opening when you aren't using the oven, and make sure you have a spark arrestor, or other way of keeping water from coming down the chimney, where it will land on our vent floor area.

Also, make sure that your oven landing -- in front of the vent landing floor piece, is also sealed so that water doesn't wick in there.

None of this is hard to do, and it will make your oven work better. A bone dry oven heats up faster and cooks better.
Hope this helps.
James

[james]

One more thing

You can mortar the vent landing piece (the kidney shaped one) in place and up to the oven dome piece, and mortar the vent landing to the front of the cooking floor. That will not compromise how the floor and dome move, and will seal the floor of the oven under the vent and outside the door.
James

[Alan]

Thanks for the guidance.