Casa 90 corner build (and outdoor kitchen) begins....

[joeykramer]

does your concrete landing come into the vent of the oven? So you only have firebricks in the floor of the oven, the 'mouth' is just concrete?

[terdferguson]

What temps should I expect right at that spot where my concrete counter runs up to the front edge of the oven floor? My concrete guy that is fabricating the counter is going to seal the concrete. He wants to make sure the sealer he selects can withstand the temperatures of that location. I told him probably 300-400 right there, but I'm not certain.

[terdferguson]

That's great Randy. I think I'll somewhat copy what you've done. I'm going to have a lip built with my concrete counter and under the lip I'll put ceramic board or blanket. Then have a small air gap filled with the rope and ash. I think this will be a winner. I only have about 7" of counter from were it meets the oven floor to the counter edge. That's not a lot, so the more I can isolate it from the heat the better.

[RandyJ]

The gap was 1\4"wide. I used 5\16" ceramic rope to fill the gap. And yes the fill on top was just ash from one of the fires. It seams to work pretty good. The front lip on my oven never seams very warm. But that I think is more from the cool air flowing over it in to the oven.

Randy

[terdferguson]

Hey Randy, that gap looks tiny that you are stuffing that ceramic rope into! How wide was that? And you topped it with ash from one of your fires?

[terdferguson]

I figured that high heat mortar supplied with my oven was probably good for expansion and contraction since it was meant to go in the seams where my 3 oven pieces come together.

David S, with your setup, what temperature do you see on the floor of your outer arch (on the cool side of your vermicrete filled heat break)?

[david s]

What is the material filling the joint between your oven floor and outer arch?

I use some ceramic blanket and then to seal it off stuff some 5:1 vermicrete over it for a depth of around 8 mm.

Your first drawing does not allow for any expansion and heat will still conduct through the high heat mortar. In the second drawing There is provision for expansion provided the insulating board you've used can be compressed somewhat.

[terdferguson]

Alright, I think I have a grip on this after looking at your pictures and reading some other heat break threads.

I've come up with two plans. This is a side view of each.





The first uses high heat mortar (that came with my casa oven) over a piece of insulating board. The mortar would help me get a nice continuous smooth surface between my concrete landing and oven floor.

The second uses the insulating board and then a small air gap (maybe 1/4" ?).

My primary goal here is safety. I want my landing out in front of the oven to be cool enough to touch. I have little kids running around in a small space. I don't want anyone getting burned. To be clear, when I say "landing" I'm talking about the grey concrete counter that you see in this picture:



That concrete counter will abut my oven floor as seen in my 2 heat break diagrams above. So all that being said, which of the two designs would be best for keeping my concrete landing cool?

[RandyJ]

I used a pice of ceramic rope and then stuffed it with ash on top of it.

Randy

[UtahBeehiver]

I suggest doing a search on heat breaks and look at all the various options and pick and choose which ones work best for you. As far as my floor heat break I used a thin wall SS rectangular tube filled with left over CaSi board.

[terdferguson]

What is the material filling the joint between your oven floor and outer arch?

[david s]

Every build is different, but in my design the heat break/expansion joint is between the outer decorative arch and the flue gallery, with the outer dome shell an integral part of the decorative arch, the two joined at the sides and the top. In the case of the oven floor mine is raised above the supporting slab so the two are not level. The overriding principle is that the oven be completely surrounded by insulation and the inner parts are free to expand independently from the outer parts.

[terdferguson]

Yes, I'll eventually make an insulated door for sure. But how do I attach my brick arch to the oven? And what about my concrete counter? How do I insulate that from the oven floor yet still have a continuous surface between oven floor and concrete counter?

[david s]

Yes, you are correct. You've added tons of insulation so it would seem crazy to allow heat loss via conduction to the front decorative arch. In addition as you point out the expanding oven will put stress on the arch. I've seen enough ovens that don't have a flexible expansion joint, with cracked decorative arches, to convince me of their value. An insulated door is also a good idea. I think you may have to fabricate it yourself., for some reason FB don't.

[terdferguson]

Guys I have a question about the landing and my brick arch. My design has my brick arch (made with regular clay bricks) attaching directly to the face of my oven and my concrete landing butting directly up against the oven floor. As seen here:



What about these things heating up? If I have the bricks and the concrete landing/counter directly against the dome and oven floor are they going to get insanely hot? Hot enough to burn someone I would assume? If so, I can't have that.

I've been reading some threads about heat breaks and what not, but I'm still not entirely clear on this. If I wanted to insulate my concrete landing/counter from the oven floor would I fill a gap between the two with something like vermicrete?