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

Like Tree12Likes

Reply
 
LinkBack Thread Tools Display Modes
  #51  
Old 02-13-2013, 03:38 AM
Master Builder
 
Join Date: Jan 2013
Location: Tochigi Prefecture, Japan
Posts: 620
Default Re: Structural Slab for new WFO

For stucco layer, are you meaning "any cement type coating" including the scratch coat, OR just the final coat that essentially waterproofs the job?
Reply With Quote
  #52  
Old 02-13-2013, 05:15 AM
david s's Avatar
Il Pizzaiolo
 
Join Date: Mar 2007
Location: Townsville, Nth Queensland,Australia
Posts: 4,684
Default Re: Structural Slab for new WFO

Quote:
Originally Posted by mikku View Post
For stucco layer, are you meaning "any cement type coating" including the scratch coat, OR just the final coat that essentially waterproofs the job?
I meant any cement layer. Removing the water without the assistance of sun and wind is going to be problematic.
Reply With Quote
  #53  
Old 02-13-2013, 12:58 PM
Master Builder
 
Join Date: Jan 2013
Location: Tochigi Prefecture, Japan
Posts: 620
Default Re: Structural Slab for new WFO

Well, that is going to mean--getting those "old wheels" bolted on and moving the assembly near the garage door opening. I have a southern exposure so the doors get opened for the mornings--

Get the drying effect from Sun and some of the dust can get blown out of the garage or vice versa. Not the same wind or sun as outdoors, but always dry.

So--this is one of the down sides of pericrete.
Thanks for the warning.

Off the wall thought.. Your seasons are opposite of the Northern Hemisphere Continents, do you typically face buildings to the North for sun exposure?
Reply With Quote
  #54  
Old 02-13-2013, 06:49 PM
david s's Avatar
Il Pizzaiolo
 
Join Date: Mar 2007
Location: Townsville, Nth Queensland,Australia
Posts: 4,684
Default Re: Structural Slab for new WFO

[QUOTE
Off the wall thought.. Your seasons are opposite of the Northern Hemisphere Continents, do you typically face buildings to the North for sun exposure?[/QUOTE]

yes that is true for southern Australia or colder regions. We live in the tropics and are not looking for any extra sun, even in the winter.
Reply With Quote
  #55  
Old 02-13-2013, 07:49 PM
Master Builder
 
Join Date: Jan 2013
Location: Tochigi Prefecture, Japan
Posts: 620
Default Re: Structural Slab for new WFO

That is very interesting!
I have always lived in a cooler climate, northern hemisphere, utilized direction for solar gain, morning sun to help usher in the day, evening sun to usher out the day--recreation spaces south/west to keep insects at bay.

Some here do planning of structures-all based upon orientation North/South, something to do with luck or superstition????. But do not know the "word" something like "fu-su-ee". Actually shows up on architects' building permit application!

Also never realized the size of Australia.. Thanks for the lesson!
Is it true about the direction water swirls as it goes to drain--different in hemispheres as well?
Reply With Quote
  #56  
Old 02-14-2013, 02:02 AM
david s's Avatar
Il Pizzaiolo
 
Join Date: Mar 2007
Location: Townsville, Nth Queensland,Australia
Posts: 4,684
Default Re: Structural Slab for new WFO

Quote:
Originally Posted by mikku View Post
That is very interesting!
I have always lived in a cooler climate, northern hemisphere, utilized direction for solar gain, morning sun to help usher in the day, evening sun to usher out the day--recreation spaces south/west to keep insects at bay.

Some here do planning of structures-all based upon orientation North/South, something to do with luck or superstition????. But do not know the "word" something like "fu-su-ee". Actually shows up on architects' building permit application!

Also never realized the size of Australia.. Thanks for the lesson!
Is it true about the direction water swirls as it goes to drain--different in hemispheres as well?
Yes the water does drain the other way in the southern hemisphere. Cyclones also rotate in a clockwise direction unlike hurricanes in the Nthn. Hemisphere which rotate anti clockwise.
Where we live nobody likes the prospect of introducing daylight saving. We are happy when the sun goes down, for us it's just heat saving.
mikku likes this.
Reply With Quote
  #57  
Old 02-14-2013, 03:40 AM
Master Builder
 
Join Date: Jan 2013
Location: Tochigi Prefecture, Japan
Posts: 620
Default Re: Structural Slab for new WFO

That is worth a good chuckle!
Reply With Quote
  #58  
Old 02-14-2013, 03:50 AM
Master Builder
 
Join Date: Jan 2013
Location: Tochigi Prefecture, Japan
Posts: 620
Default Re: Structural Slab for new WFO

Progress on insulation.

Structural Slab for new WFO-img_2596a.jpg

That is far as I can go without a chimney!
Tried to make the top of the dome insulation thicker- but now it looks like one of the "cone heads"! A few bumps and dips--but better than I expected from eye-balling it only.
Just have to call it character!

I was surprised, this morning I was able to shave some of the edges using an OLFA cutter. The insulation is still very fragile, but it cut like styrofoam.

There are places where this stuff is over 6" thick--(near the inner door opening), lots of water to dry out!
Reply With Quote
  #59  
Old 02-14-2013, 06:13 PM
Master Builder
 
Join Date: Jan 2013
Location: Tochigi Prefecture, Japan
Posts: 620
Default Re: Structural Slab for new WFO

Question time again:

1) I have been warned about getting all the water out of the insulation prior to rendering.

2) Today, the insulated pericrete dome when tapped returns a hollow type sound.

3) I did not clean out the wheelbarrow used for mixing yesterday--but the dry stuff left from yesterday shows no properties of firmness--simply crumbles if you roll it around in your hand. But that material was not pressed into place or tamped in any fashion.

4) Yesterday, when adding the second level to the dome, I wet the dome--and you could visibly see it absorbed into the refractory... the water placed on the previous days pericrete--simply disappeared with no sign of color change from absorption.

Here are the questions:

1) Does this pericrete reach an "ultimate strength" after a certain number of days?

2) If so--by experience, how many? Like concrete approx. 28 days?

3) Will it develop a structure where I do not have to be careful about bumping it without fear of it crumbling to powder?

4) Given the fact that this material is extremely porous, and that a render coat will re-introduce a significant amount of water... and the strength of the render will be dependant upon a slower dry (for hydration)... would it not make sense to do the render sooner, rather than later BUT leave a significant opening...like Gulf describes for venting moisture?

5) I am dealing with a slightly mobile build--I worry about jacking up the slab to install the wheels--and any vibration to the slab by moving... I really don't want a chunk of this insulation to fall off like an egg shell!

6) The other upcoming event will be a curing fire--so far "done outdoors" unless I use the "propane fire ring" technique or "heat beads" with the garage doors open. Both techniques, however, require a final burn using wood to get the high temps. This would involve moving everything outdoors via forklift and possible-bumping, twisting, etc. forces---that a render might protect!

My structural slab is quite rigid--visibly at least, if the base is not supported equally, it will rock rather than flex.. But this pericrete seems very brittle!

Only someone who has worked with pericrete can answer these questions because they have actually observed the characteristics of a 10:1 mix as it is installed and as it ages!

I can see no reason for anyone to build up pericrete in 1" layers over a dome!
I saw on another website, someone advocating the use of lime with portland & vermiculite/perlite --only reason I can see would for it to adhere easier in thin coats...But this would also decrease the insulative properties?

Sorry for the "longwindedness" but a lot of questions requiring answers.
Also must evaluate risks vs advantages in the build!
Reply With Quote
  #60  
Old 02-14-2013, 10:50 PM
david s's Avatar
Il Pizzaiolo
 
Join Date: Mar 2007
Location: Townsville, Nth Queensland,Australia
Posts: 4,684
Default Re: Structural Slab for new WFO

Quote:
Originally Posted by mikku View Post
.

Here are the questions:

1) Does this pericrete reach an "ultimate strength" after a certain number of days?

2) If so--by experience, how many? Like concrete approx. 28 days?

3) Will it develop a structure where I do not have to be careful about bumping it without fear of it crumbling to powder?

4) Given the fact that this material is extremely porous, and that a render coat will re-introduce a significant amount of water... and the strength of the render will be dependant upon a slower dry (for hydration)... would it not make sense to do the render sooner, rather than later BUT leave a significant opening...like Gulf describes for venting moisture?

5) I am dealing with a slightly mobile build--I worry about jacking up the slab to install the wheels--and any vibration to the slab by moving... I really don't want a chunk of this insulation to fall off like an egg shell!

6) The other upcoming event will be a curing fire--so far "done outdoors" unless I use the "propane fire ring" technique or "heat beads" with the garage doors open. Both techniques, however, require a final burn using wood to get the high temps. This would involve moving everything outdoors via forklift and possible-bumping, twisting, etc. forces---that a render might protect!

My structural slab is quite rigid--visibly at least, if the base is not supported equally, it will rock rather than flex.. But this pericrete seems very brittle!

Only someone who has worked with pericrete can answer these questions because they have actually observed the characteristics of a 10:1 mix as it is installed and as it ages!

I can see no reason for anyone to build up pericrete in 1" layers over a dome!
I saw on another website, someone advocating the use of lime with portland & vermiculite/perlite --only reason I can see would for it to adhere easier in thin coats...But this would also decrease the insulative properties?

Sorry for the "longwindedness" but a lot of questions requiring answers.
Also must evaluate risks vs advantages in the build!

1.Because perlcrete or vermicrete is made with portland cement it continues to increase in strength over time. One week is generally sufficient. A vermicrete mix contains about double the water needed for hydration so there is plenty of moisture there for this stage.

2. Only if you are making a ferrocement boat or high strength concrete would you require 28 days. the difference is minimal (look at a strength vs time graph of concrete strength)

3.No it will always be weak. But it only needs to be strong enough to stand up vertically and be firm enough to render over. The more cement you put into the mix the stronger it will be, but you drastically reduce its insulating value if you do.

4.There is some sense in this , but water left in this layer presents problems in removal. I take the view that it is better to dry the insuation layer completely, render over it ,then seal the render layer for a week using cling wrap.

5. If any falls off it's easy enough to patch it up.

6.The reason I advocate doing the vermicrete in 1" layers is so it has a better chance to dry. If you do it all in one layer it is much slower to dry the stuff that is buried deeper.

Last edited by david s; 02-14-2013 at 10:54 PM.
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
Started in Napa, WFO dome & slab questions EricU Getting Started 9 08-01-2010 12:08 PM
Foundation Slab Questions achilles007 Newbie Forum 5 07-06-2009 04:52 PM
structural slab question rbigante Pompeii Oven Construction 2 10-01-2008 07:44 PM
structural slab question rbigante Pompeii Oven Construction 5 09-29-2008 10:42 AM
New hearth slab design question DrakeRemoray Pompeii Oven Construction 6 04-24-2006 01:42 PM


All times are GMT -7. The time now is 07:27 PM.

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