still lots of questions

[waynebergman]

Will be adding the insulating pour to the hearth this weekend. I have read we dont need to go too far past the footprint of the oven with this mixture. I would prefer to just fill in the entire circle shown here in the attachment. I have about 62" in diameter here to fill. Thought it would be easier to just fill it all. I plan to put an expansion joint at edge of outer ring in case there is any expansion differences between the two different pours. Maybe fill in the top of this joint with some automotive gasket gunk of silicone to stop water from entering and freezing. Is there a problem or advantage to going with the insulating pour for the whole area? Is it as strong as regular concrete? I thought it would help with heat getting to areas that I would rather have cool like on the outer perimeter of oven landing etc.
Also a second issue....the manual sugests 2 landings of 4" and 12" . This makes 16" if I am reading into this right. Outbound from the internal perimeter of oven at opening? I was going to use firebrick as I have lots for this whole area. Is that ok? Also is the 16" to be measured from the vent opening right where it meets the oven floor or where exactly does this 16" start from. Its hard to see from the pictures in Manual but I get the feeling its not super important but thought I better check.
Thanks in advance....Wayne...... Garden Bay BC Canada
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[christo]

Re: still lots of questions

I've seen many vermiculite concrete pours where they do just what you are suggesting. I don't think you need to worry about expansion and contraction between the vermiculte concrete and the foundation. I do not think the vermiculite concrete has enough strength in compression to compromise your foundation. The experts on the list may contradict me, but I also feel if the vermiculite base expands against the foundation, any compression or crumbling of the vermiculite concrete will be near the area of contact with the foudation ring and should not have any impact under your oven base.

There is some high temp silicone caulk available at hardware stores and fireplace stores that you could use to fill in gaps where temperature exceeds normal silicone applications.

I have seen several materials used for landings but many people use firebrick successfully. I used firebrick for the large area of the landing and a 4 inch wide piece of granite to finish off the front edge. There are some care issues with granite (regular sealing) but I really like the look.

Christo