Building in Central Florida, Question about insulation beneath cooking floor

[glowthb]

Re: Building in Central Florida, Question about insulation beneath cooking floor

Yeah...I was very appreciative to the guys at Cemex for letting me interupt their inventory to sell be some bricks. As much as it pained me I would have waited until next week to lay the floor had they not.

Attached are some photos. As you can see I went a little unorthodox by using some metal framing track to edge the insulation. As I stated earlier I was not thrilled with the vermicrete mixture I poured over the K-23. It appears to be completely firm but I was concerned that the edges might crumble eventually under weight. I figured the framing couldn't hurt...a little peace of mind.

Cannot wait to get up in the morning and begin working the dome.

[efleifel]

Re: Building in Central Florida, Question about insulation beneath cooking floor

Great , I was going to suggest that you invest in better bricks for the floor, glad you did already. When you have a chance post some photos so that we can see.
I was planning to close the dome today, but could not, there was a lot of brick cutting due to the smaller and smaller circle, but I am determined to finish tomorrow.
Cheers
Eddie

My Web site

[glowthb]

Re: Building in Central Florida, Question about insulation beneath cooking floor

Dropped by Cemex today. They happened to be in the office doing inventory and were kind enough to let me compare their fire brick to what I had from Harwood. Cemex's bricks were far better showing no sign of surface crust or flakes like the ones I already had. I bought enough to use for the cooking floor and got it laid in today.

Tomorrow I will begin getting the first couple of courses of the dome in....cannot wait!

[glowthb]

Re: Building in Central Florida, Question about insulation beneath cooking floor

Eddie,

Good luck on the dome. Yeah...had I known Cemex had the fire brick I would have gone there since it is a few miles closer. They should answer there phone once in awhile.

My fire brick does have some flaking on the outer layer. Should I be concerned about this? I am considering trying to use a vibrating sander to smooth and take the top layer off the brick on the floor.

I plan on getting the floor down and hopefully a few courses of brick this weekend. We will see how it goes.

[efleifel]

Re: Building in Central Florida, Question about insulation beneath cooking floor

Great,

I bought the 4 cubic ft vermiculite from Lucas at $21.00 per bag, but it is the same that I used in my previous build in Jacksonville, and it was a good grade, I mixed it with portland cement with a ratio of 7:1. It works, I cooked my pizza in 90 seconds @ 750 degrees. the bricks at Cemex are 4.5X9X2.25 for $1.30 while the bricks at Harwood in Longwood are 4X8X2.25 for 1.25, it is more or less the same, your choice. bouna fortuna
I am planning to close the dome this weekend, wish me luck.

Cheers

Eddie

My Web site

[glowthb]

Re: Building in Central Florida, Question about insulation beneath cooking floor

Thanks for all the input.

I had an engineer at work take a look at the data sheet for the K-23 and Insblock 19. The K-23 is only marginally less efficient as an insulator then the insblock 19 so I went with the K23 I could get locally. I had already purchased vermiculite from Lucas but it was the fine agricultural grade. I decided to vermicrete around and over the K-23 so there is about another inch of vermicrete over the K-23.

I am not to pleased with how the vermicrete set. Seems more like packed soil or cork after 48 hours of drying. Not sure if I should pour a slurry of concrete over the vermicrete and let it set some more or not. The vermicrete appears to be very firm from the top but I am concerned once I pop the form off the edges may have some crumbling. I may frame it with some Hardibacker to hold it together.

Eddie, I got the fire brick and fireclay over by Dogtrack Road at Harwood Brick...$1.25 a brick.

I was hoping to begin the oven this weekend but may need to re-assess this insulation layer before I move forward.

[efleifel]

Re: Building in Central Florida, Question about insulation beneath cooking floor

Hello,

A message to glowthb.

I live in Oviedo as well, and was able to get all the material locally. I got the vermiculite from Lucas Nursery, and the firebricks and the HeatStop mortar from Cemex; corner of Forsyth and Aloma.

Let me know if you still have questions or if you are already on your merry way with the build
good luck

Eddie
Salute
My Web site

[azpizzanut]

Re: Building in Central Florida, Question about insulation beneath cooking floor

Yikes ! HD seems to sell a lot of it though.

Cheers,

[Tscarborough]

Re: Building in Central Florida, Question about insulation beneath cooking floor

10-12 bucks for 4 cubic foot is reasonable. 35 bucks is robbery.

[SteveP]

Re: Building in Central Florida, Question about insulation beneath cooking floor

$35 for 4 cu ft bag of Perlite seems pretty high. I paid $9 for 4 cu ft bags of perlite at a nursery supply warehouse in Ft. Pierce. I used to live in Winter Springs and I would assume you would be able to find it cheaper than $35/bag.

[azpizzanut]

Re: Building in Central Florida, Question about insulation beneath cooking floor

Hello,

K23 insulating brick is often used in ceramics kilns. There are other insulating fire bricks to consider though, K29 for example.

I made a 42" insulating hearth from Thermo Ceramics brand Kaolite. Three bags @ $45 per bag. It is a castable insulating refractory product. My wife made a brick paver from the small amount left over and it is light as a feather. Another hearth has four inches of perlite/portland (5:1) with one inch of Kaolite on top of that. Overall, the most cost effective is perlite/portland. Do wear a mask when handling pelite, cough, cough !! The dust is easily raised no matter how careful you are.

Shop around for perlite. I bought a 6 cu ft bag at a builders supply for $28. HD has commercial grade perlite available 2 cu ft for $17.....go figure. The product from the builders supply said in small print "Water resistant". However, it mixed as easily as the perlite from HD, no problem at all.

Cheers,

[dmun]

Re: Building in Central Florida, Question about insulation beneath cooking floor

Insblock19 is the brand name of the mineral fiber board made by Harbison-Walker, the nations biggest refractory manufacturer. They have distributors all over the country, but I found I could buy it for less elsewhere. It's good stuff.

[ThermoJax]

Re: Building in Central Florida, Question about insulation beneath cooking floor

I am in North Florida and I got the insblock 19 from atlantic firebrick here in Jacksonville. It is great stuff. I did not use the Vermicrete. I also purchased the related blanket product for wrapping the dome. I was worried as my concrete pad was warm during the curing process, but it is not warm now. I also put a bunch of r-13 insulation over the ceramic insulating blanket. The Vermicrete mix looks hard to use and I think it might take a while to dry enough for the next step. Purchase the insblock 19 and forge ahead.

Good Luck

[GianniFocaccia]

Re: Building in Central Florida, Question about insulation beneath cooking floor

Yes, the FB plans call for either 4" of vermiculite/perlite insulation or 2" of an insulating fiber board. A growing number of builders are incorporating a combination of the two. Insblock 19 is popular with builders because it is effective and reasonably priced. A good discussion on it can be found here:

http://www.fornobravo.com/forum/f6/k-fac-19-a-3031.html

[glowthb]

Re: Building in Central Florida, Question about insulation beneath cooking floor

Gianni..and all thanks for the advice. I want to make sure I understand the comments so I use the best material available locally.

1. Insulated fire brick (IFB) and vermiculite/perlite would both require 4 inches to get the same insulation? So the single 2.5 inch layer of IFB would not be sufficient insulation?

2. What is Insblock 19?

Thanks again.