clever idea or bad mistake?

[TimEnzweiler]

I incorporated what seemed to be a good idea of recessing a 2" "pit" into my poured concrete base for the FB insulation board. Now I'm concerned I have created a moisture problem whenever rainwater enters my oven and leaches into the insulation bard pit. Comments?

[mrchipster]

Re: clever idea or bad mistake?

I incorporated what seemed to be a good idea of recessing a 2" "pit" into my poured concrete base for the FB insulation board. Now I'm concerned I have created a moisture problem whenever rainwater enters my oven and leaches into the insulation bard pit. Comments?

Tim,

I think you will be OK if you are careful with your roof and storm door.

I did the same design but my main reason was to be able to use a lower Vermicrete mix for improved insulation performance, I poured 2.5 inches of 7:1 vermicrete and then used 2" of FB board over the top i believe I should have used 10:1 Vermicrete because it is contained in the concrete form and with the board over it it would have been plenty strong and had better thermal insulation value.

I think as long as you have a roof over your oven and use some type of storm door at the decorative arch I think there will be no problem. You live in an area that gets lots of rain so I would shy away from an igloo style.

One other thing, I did NOT run my "pit beyond my flue arch The entire decorative arch sits on concrete so there is a 3" area of concrete before getting to the pit. My storm door will sit on this outside area. This area also slopes away from the oven slightly.

I did incorporate thermal breaks at both the inner and outer arches, and i am not seeing any significant thermal bleed to the decorative arch.

I think the third photo shows that the decorative arch sits on concrete best and the floor brick under the Stainless is also sitting on concrete for about 1 inch. There is Vermicrete under the rest of the Stainless just brick at the outer edge for durability.

Chip

[GianniFocaccia]

Re: clever idea or bad mistake?

Hey Tim,

Other builders have recessed their floor insulation into the support slab either to 'containerize' a vermicrete layer (like Chip) or to protect the entire insulation layer or both. I went 5 1/2" deep to accommodate 3 1/2" of vermicrete and a 2" layer of ceramic board. It's whatever you want to do. Yeah, moisture can get under your insulation but it always dries out.

If nobody steps outside the box then none of us benefit from new ideas (good or bad).
John

[david s]

Re: clever idea or bad mistake?

I made a recess in my supporting slab and should it accumulate water I placed a small drain hole in the centre covered with fly mesh. I also sloped the outer surrounding part of the supporting slab slightly to discourage water flowing under the base of the dome. This requires thinking ahead but I think it's worth it.

[SpottedFrog]

Re: clever idea or bad mistake?

Thanks for this thread, after reading about the exploding floor on another thread I have been wondering about rain getting under the floor. Many useful tips here I am at the stage of collecting materials. Am planning on Pompeii style about 42" ID. I will be facing my oven door away from the main rain direction but with the weather we have been having lately who knows where it will be coming from next.
Cheers Rosemary