Weather resistant plaster for clay oven

[lancepawl]

Denzer's Earth Oven book says a finishing water resistant layer can be a plaster made of fresh cow manure or a plaster made of mason't lime. Anyone have experience with either and how well they would work to protect an oven in a four season climate, that is, we get plenty of rain and snow where I live. I'm thinking that there is no way either of these plasters could really protect the oven from the elements long term with the result that the oven only lasts for a year or two.

I've also read that a water proof layer absolutely will not work for a clay oven since interior moisture cannot escape and collects between the waterproof layer and the clay and that will cause the inside of the clay dome to break up and crumble over time.

Probably the only way is to have a roof and enclosure for the oven but that is not without complications.

Any first hand experience or suggestions for the above would be appreciated.

[BackyardPermaculture]

Re: Weather resistant plaster for clay oven

I went with the final option (roof and enclosure) - I just left enough ventilation under the eaves. Really happy with it so far - clay oven performing really well. Just make sure to insulate well, especially under the hearth.

Cheers,
Mick

[lancepawl]

Re: Weather resistant plaster for clay oven

Hello Mick,
Thanks. I have decided to do that too. It's the only way that I can be sure that weather won't impact the oven. I also used a wood base. It's attached to the deck and of 4 x 4's. I have a 5 to 1 vermiculite / portland cement insulating layer poured on top the 4 x 4's, then the hearth and then firebricks for the oven floor. BTW, nice oven you have.
Regards,
Lance