Go Back   Forno Bravo Forum: The Wood-Fired Oven Community > Pizza Oven Design and Installation > Getting Started

Like Tree36Likes

Reply
 
LinkBack Thread Tools Display Modes
  #11  
Old 12-12-2011, 12:17 PM
deejayoh's Avatar
Il Pizzaiolo
 
Join Date: Jul 2010
Location: Seattle
Posts: 1,380
Default Re: Starting new 36" build

Quote:
Originally Posted by brickie in oz View Post
A concrete pier/pile at the back would alleviate that problem and help carry the load, the slab could also be suspended off the soil via the pier/pile to help with the moisture issue that will arise.
I really don't want to suspend the slab if I can avoid it. I don't see how moisture can travel up through a waterproof barrier into a slab. But settling is a concern. The dirt behind the wall was backfilled after the wall went in, and looking at it this weekend I can see it has already compacted about an inch in the past few months. I was thinking I could pack it down really well - but maybe I should drop a couple sonotube forms in the corners? There is a clay layer down about 2-3 feet that you need a jackhammer to break up.

Quote:
Id be putting lots of waterproofer in the hearth slab too as moisture will travel into the slab from the retaining wall, it doesnt take much moisture to make an oven under perform.
Not sure what you mean by waterproofer. Are there additives for the concrete, or do you just mean sealants?

on the moisture issue, I was thinking that since the retaining wall is a separate structure, and below the hearth - that moisture shouldn't be able to wick into the hearth if I hadthe protection on the bottom. But I'll be the first to say I have minimal knowledge of concrete!

TIA for the guidance

Dennis
Reply With Quote
  #12  
Old 12-12-2011, 12:29 PM
brickie in oz's Avatar
Il Pizzaiolo
 
Join Date: Mar 2009
Location: Whittlesea
Posts: 3,455
Default Re: Starting new 36" build

Quote:
Originally Posted by deejayoh View Post
maybe I should drop a couple sonotube forms in the corners?
That would stop any settlement issues for sure.



Quote:
Originally Posted by deejayoh View Post
Are there additives for the concrete,
Correct, add them at the mixing stage and the concrete wont wick any moisture.


Quote:
Originally Posted by deejayoh View Post
on the moisture issue, I was thinking that since the retaining wall is a separate structure, and below the hearth - that moisture shouldn't be able to wick into the hearth if I hadthe protection on the bottom. But I'll be the first to say I have minimal knowledge of concrete!
Ive seen moisture travel 6' up masonry over time, if you put a physical barrier in place it would help too.

Better to be safe than sorry, there have been a few tales of woe on the forum all due to moisture wicking, once it starts to wick after a build it would be almost impossible to stop without a pull down and restart.

Same goes for heat wicking, best to get it sorted out before the build.
__________________
The English language was invented by people who couldnt spell.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.



To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

Last edited by brickie in oz; 12-20-2011 at 08:44 PM.
Reply With Quote
  #13  
Old 12-13-2011, 01:07 PM
deejayoh's Avatar
Il Pizzaiolo
 
Join Date: Jul 2010
Location: Seattle
Posts: 1,380
Default Re: Starting new 36" build

Thanks Al - I also read your comments in the Insulation sticky thread

So, paying close attention here. I did some searching with the google and came up with Xypex, an additive that you incorporate in the mix that is supposed to prevent water wicking

Xypex Corporation

So I am thinking of using this (assuming I can find it!) along with a moisture barrier to have a hearth layer that is moisture impermeable.

On top of that, I'm thinking 3 inches of insulating board - local supplier doesn't say which this is but I will go with theirs or the FB board from our sponsor.

Seattle Pottery Supply E-Catalog: Insulating Board - BACKUP BOARD - 1900 Degree F. - 12 in x 36 in x 1 in - 16 Piece/Case

Think that will be sufficient?
Reply With Quote
  #14  
Old 12-13-2011, 06:37 PM
brickie in oz's Avatar
Il Pizzaiolo
 
Join Date: Mar 2009
Location: Whittlesea
Posts: 3,455
Default Re: Starting new 36" build

Quote:
Originally Posted by deejayoh View Post
So, paying close attention here. I did some searching with the google and came up with Xypex, an additive that you incorporate in the mix that is supposed to prevent water wicking

Xypex Corporation

So I am thinking of using this (assuming I can find it!) along with a moisture barrier to have a hearth layer that is moisture impermeable.
The spec sheet reads ok apart from only being able to buy larger than needed parcels of it.
You should ask a hardware store about it or equivalent stuff.

Quote:
Originally Posted by deejayoh View Post
On top of that, I'm thinking 3 inches of insulating board - local supplier doesn't say which this is but I will go with theirs or the FB board from our sponsor.

Seattle Pottery Supply E-Catalog: Insulating Board - BACKUP BOARD - 1900 Degree F. - 12 in x 36 in x 1 in - 16 Piece/Case

Think that will be sufficient?
3" of Calcium Silicate board may be overkill?
I have 40mm underneath my hearth and the oven stays hot for days and days.
__________________
The English language was invented by people who couldnt spell.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.



To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Reply With Quote
  #15  
Old 02-11-2012, 03:24 PM
deejayoh's Avatar
Il Pizzaiolo
 
Join Date: Jul 2010
Location: Seattle
Posts: 1,380
Default Re: Starting new 36" build

Well, we are into February, but I am finally seeing some progress on my build.

Couple of changes from my initial post:
  • I have decided to go with a 39" oven instead of a 36". almost went with a 42" but made a firewood vs. stairs tradeoff
  • I decided to pour the lintel rather than use concrete block supported by angle irons. I figure the angle irons are going to rust over time and leave stains at best

So I got the stand built a couple of weeks ago, and today I hired a couple of guys from my friends construction crew to help me pour the lintel. Actually, I thought I would get the hearth poured too, but the &*!@ Salmon Bay Concrete store is closed on Saturday, so I could not pick up the Xypex AdMix C-1000 that I am putting in the hearth to make it waterproof.

Let me tell you, this stuff is super pricey. You mix it in at 2% of the weight of the concrete, and it's $6 per pound.... More than the concrete, but I figure safe is better than sorry.

I also have my ceramic blanket and duravent already on hand, so I am a bit ahead of the game there. Just need to get the bricks, mortar and FB board.

Finished Stand

Forms ready for hearth

Pouring the lintel
Reply With Quote
  #16  
Old 02-21-2012, 04:30 PM
deejayoh's Avatar
Il Pizzaiolo
 
Join Date: Jul 2010
Location: Seattle
Posts: 1,380
Default Re: Starting new 36" build

I have a question about insulation between the hearth layer and the cooking floor:

I purchased 2" of FB Board insulation to install under my oven. The spec sheet for the board says that:
"One 2" thick layer of FB Board panel reduces the 800F cooking floor of a pizza oven to roughly 170F at equilibrium"
I have seen recommendations for 2 layers (4") of the FB board on the board. That seems like total overkill to me - as the goal of the floor insulation should be to reduce the heat transfer to the point where it is equivalent to roughly the temperature of the hearth - about another 100-130 degrees

Beyond that point, you really aren't losing any heat so you are past the point of diminishing marginal returns from insulation

I am trying to figure out if there is a cheaper material I can use at 1" thickness to accomplish that last bit of temperature reduction. Something I can source locally that is more in the $5/sq foot price range than the $12 per sq foot that the FB board costs.

Any suggestions? Would an inch of perlite do the trick?
Reply With Quote
  #17  
Old 02-21-2012, 05:08 PM
GianniFocaccia's Avatar
Il Pizzaiolo
 
Join Date: Jun 2009
Location: Disneyland, CA
Posts: 1,491
Default Re: Starting new 36" build

1" of ceramic board is equal to 2" of vermicrete or perlcrete. I put in 3 1/2" of vermicrete (easy to mix and install) under 2" of board, which is becoming common. 1" of perlcrete isn't going to do much for you.
Reply With Quote
  #18  
Old 02-21-2012, 05:22 PM
deejayoh's Avatar
Il Pizzaiolo
 
Join Date: Jul 2010
Location: Seattle
Posts: 1,380
Default Re: Starting new 36" build

Quote:
Originally Posted by GianniFocaccia View Post
1" of ceramic board is equal to 2" of vermicrete or perlcrete. I put in 3 1/2" of vermicrete (easy to mix and install) under 2" of board, which is becoming common. 1" of perlcrete isn't going to do much for you.
Thanks Gianni
So it takes 3 1/2 inches of vermicrete to manage 170 degree temperature? Seems like a pretty inefficient insulator.

Due to height limitations I am looking for something no more than 1" thick

I saw this at our local pottery supply. This board looks like it might do the trick. Any thoughts?
Reply With Quote
  #19  
Old 02-21-2012, 06:57 PM
GianniFocaccia's Avatar
Il Pizzaiolo
 
Join Date: Jun 2009
Location: Disneyland, CA
Posts: 1,491
Default Re: Starting new 36" build

Can't tell, DJO. Maybe you can email them and ask for the board's R-Value and MSDS, which will tell you the board's composition. Since you'd be using it as backup instead of hot-face insulation, I'd be tempted to use it as long as it's compressive strength is acceptable.
Reply With Quote
  #20  
Old 02-22-2012, 08:54 AM
deejayoh's Avatar
Il Pizzaiolo
 
Join Date: Jul 2010
Location: Seattle
Posts: 1,380
Default Re: Starting new 36" build

Thanks gianni. BTW, I have learned a lot from reading about your build, as I get ready to start cutting bricks on mine.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Just starting my build WoodchuckDad Introductions 25 04-16-2010 05:28 PM
Matt's WFO Build mluttropp Pompeii Oven Construction 74 11-22-2009 03:27 PM
Newbie starting small oven build David D Introductions 17 11-13-2009 01:37 AM
Starting the build on Monday!! Ellie Pompeii Oven Construction 5 01-18-2009 02:51 PM
Starting My Oven Build: Couple of Questions tomtom Newbie Forum 7 11-29-2008 01:15 PM


All times are GMT -7. The time now is 09:09 AM.

Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.6.0
2006/10 Forno Bravo, LLC