Floor Insulation

[johnfm43]

I have run into a problem. I poured my hearth insulation and concrete yesterday. When I removed the boards, somehow I only have 2 1/2 to 3 inches of Vermiculite layer. I know that most have talked about a 4" layer. Has anyone used their oven with a 2 1/2 inch thickness of insulation? What is the major draw back for this screw up.

I would pour more or purchase some FB board insulation except my Floor height is 47" already using 2 inches of board will obviously bring it up to 49". My wife is only 5'4" and I am already concerned about the height of the floor. HELP.

[SCChris]

Re: Floor Insulation

Insulation is your friend and more on the floor is better. I’d look at if you can either step up where you stand or bring the whole patio area up. It looks like what you have is waiting to have a patio slab poured. Is this correct?

Chris

[brickie in oz]

Re: Floor Insulation

Dig it out and replace it with calcium silicate board, the board has more insulating properties than vermicrete.

Im not a fan of vermicrete to start with, all that effort when you can just buy a board to plonk down and its done.

[johnfm43]

Re: Floor Insulation

No actually my slab is already poured. Is tearing it out and using board the only solution I have. What is the problem with only 2 1/2" under floor?

[brickie in oz]

Re: Floor Insulation

What is the problem with only 2 1/2" under floor?

They recommend 100mm and it must be for the minimum amount, more obviously would be better.

Yet 40mm of board does the same job, Ive got 40mm of board under my oven.

I actually think the vermicrete would work out more expensive in the end compared to using a board.

Anyone done comparisons in price?

No actually my slab is already poured.

But you will only be taking out the vermicrete, not the concrete.

[Les]

Re: Floor Insulation

Can you compromise on the height and add just one inch of board. The result would be better than 3 1/2 of vermiculite. Or add the 2 inches and buy your wife some cooking pumps...

[turkey]

Re: Floor Insulation

do you already have 2" of FB board? or thinking how high it would be with it?

[RTflorida]

Re: Floor Insulation

less heat retention.
If you are only planning to use it for pizza with a fire off to the side, you should be able to maintain the desired temps. You will probably have issues with bread baking and roasting. Too little insulation leads to more rapid bleed off of the heat retained within the bricks, which in turn will cause a more rapid cool down within the oven.

Best to stick with a known and proven plan = at least 2" of board or at least 4" of perlite/vermiculite concrete.

There have been many threads from those who have stumbled upon this forum after they or "a friend who builds ovens" have completed their ovens with too little, wrong materials, or no insulation. To fix after the fact is extremely problematic and many times ineffective. You are at a point where correcting the problem is not much work and not too much of an expense.

RT

[RTflorida]

Re: Floor Insulation

I think Les offers the best compromise, add 1" of board. No chipping out whats there, just lay the board and move on. Even for you wife, that 1" in added height isn't going to be noticeable, unless you tell her things are taller than planned.

RT

[johnfm43]

Re: Floor Insulation

I do not see 1" board for sale on their website. Can some one direct me to the link.
thanks

[RTflorida]

Re: Floor Insulation

The FB store only carries the 2". You will have to source somewhere else locally or on the internet. Harbison Walker has distribution centers in San Fran and LA, are you close to either? They make board from 1/4" up to 4" thick.
Might want to try ebay as well, at times I have seen some pretty good pricing on both board and blanket...gotta watch the shipping charges, though.
Maybe a local pottery or kiln supplier?.

RT

[SCChris]

Re: Floor Insulation

I like Les's Pumps idea.

[GianniFocaccia]

Re: Floor Insulation

The Insblock 19 that I got from Harbison Walker (ANH Refractories) came in 1'x3's that were two 1" thick panels sandwiched together. They actually came apart quite easily as if glued together with cornstarch. A box of eight 2"-thick panels would give you plenty of 1" insulation plus enough for an insulated door and a thermal break or two.

[johnfm43]

Re: Floor Insulation

Thanks for the advice. I thought that is what I was going to do. I was just hopeing that I could get away with it. But, from reading this forum for the past three years, I knew that I just needed to fix it. My wife told me today to just raise it 2 more inches and build her and the kids a step.

Thanks again.
johnfm43

[dmun]

Re: Floor Insulation

My wife told me today to just raise it 2 more inches and build her and the kids a step.

Yep, it's easier to raise the patio than to lower it. You'll never regret using too much insulation.