42” build in Port Renfrew Canada

[Hunterworks]

Hey all. Amazing website here and so happy to have found it. We live in Port Renfrew on Vancouver island. Just starting our build today after pouring over the website.
Our concerns here are rain and moisture. We see over 10 feet of rain a year here. I’m building the WFO in a place where the front half of the oven is covered by a existing roof , so you can cook and access it out of the rain.
It’s very expensive to source fire bricks here, but we have access to red clay bricks that where made on the island in the early 1900’s. I’m planning on using the red bricks for the stand and dome, then purchasing new smooth firebricks for the floor.
Will post pictures as we get going !
My first question is regarding insulation for the floor. Does anyone have any recommendations for insulation in a rainy climate ? Cheers

[Gulf]

Hi Hunterworks,

Welcome to the forum. My best advice is to extend the roof to include the back half of the oven. The best insulations on the market require being dry. UtahBeehiver would be able to advise you on foam glass for an under floor insulation that does not wick water from the concrete hearth. But, you would still need a better insulation between it and the firebrick floor.

[Hunterworks]

Thanks for the quick reply and add.
I’m pouring my foundation wensday and will add some post saddles to extend my roof to cover the whole oven. Will look into the foam glass now. Thanks again.

[Hunterworks]

Do you think pouring a insulated hearth with 5 inches of vermiculite concrete would work better in a wet climate such as mine ?

[UtahBeehiver]

Having a roof over the oven will go a long way to reducing insulation getting wet. Be sure to install several weep holes in the concrete support hearth. CaSi board is the most effecient floor insulation but V or Pcrete is not too bad. I installed FoamGlas then CaSi on top, FoamGlas will not absorb water. Another option is to slightly raise CaSi board off concrete via chech ceramic tile with ungrouted joints leading to weep holes. Lots of ways to skin the cat, it is a matter of material availability and budget.

[Hunterworks]

Does anyone have any recommendations for a type and thickness of casi board or ceramic fibreboard? Looking to order it online and not having any luck finding carriers in Canada.

[Hunterworks]

I found foam glass ! Brock White in Victoria BC can order it in. As well as dry refractory cement, and FB blanket. No luck on casi board, but am planning on using 3 inches of foam glass, and hopefully sourcing a 1/2 of casiboard soon.
Also found the search engine on this website. Took me a while. Things are well slab is poured and nice week of sun next week for the stand and hearth !

[UtahBeehiver]

FYI, FoamGlas has a max temp range of 900 F so you should have CaSi on top of FoamGlas. The FoamGlas has high compressive strength, good K values and will not absorb water but it abrades easily so you have to be a little careful with you toes banging against it when you are building the dome and does not have good shear strength (but that is not an issue sitting on a concrete hearth)

[Hunterworks]

Thanks for the heads up. I’ll treat it carefully, for the price of it have to be extra careful. Anything else I could use on top of it in lúe of casi?
Also any tips on cutting the foam glass to size ? I plan on cutting my brick with the foam glass and fire brick floor on the inside of the doom.

[Hunterworks]

I have a surplus of ceramic tile left over from a job I just did. I Understand ceramic tile to be a good insulator. I’m wondering if I could use a layer of ceramic tile on top of the foam glass as a heat break to keep the foam glass from reaching max temp.

[UtahBeehiver]

Most likely you will not see the max 900 F on the bottom side of the firebrick floor, just a precaution and heads up on the FoamGlas specs. That said, a layer of p or vcrete 5 to 1 is an option in lieu of CaSi. FoamGlas cuts very easily with a jig saw. Ceramic tile is not really a great insulator with a K value of 4-5 (thermal conductivity)

[Gulf]

I plan on cutting my brick with the foam glass and fire brick floor on the inside of the doom.

I'm not sure that I understand this statement, but (just like the oven floor) the dome needs to be separated from the concrete hearth with insulation. It also needs elevating with the same considerations for moisture as does the oven floor.

[Hunterworks]

Thanks guys. I found a suppler of thermo 12 gold and have it on order now.
I was planning on cutting the floor insulation , and fire bricks to fit inside the dome. And raising the floor insulation off the cement with ceramic tiles.
Should I be building the dome on top of the floor and insulation instead?
Thanks for the help we just finished cementing in our blocks

[Gulf]

I was planning on cutting the floor insulation , and fire bricks to fit inside the dome. And raising the floor insulation off the cement with ceramic tiles.
Should I be building the dome on top of the floor and insulation instead?

Definately! It is not a big deal if the dome is layed on top of the floor brick or that the floor brick are cut to fit inside the dome. But, both should be separated from the concrete hearth with insulation. If not, the dome touching the concrete hearth or the tile which is placed on that will loose vast amounts of heat. Ceramic tile is not insulation. The oven will perform very well.

[JacksonC23]

First off, the roof is a definite must for insulation. As for the floor, foam glass is ok I guess.