#1  
Old 07-22-2009, 11:36 AM
Serf
 
Join Date: Jul 2009
Location: Virgina
Posts: 2
Default vermiculite/portland and weather

I will be ready to add insulation to my slab in a few days for my WFO here in southwest VA and have a question re. vermiculite/Portland.

Is this mixture weather resistant? I plan to extend the insulation past the edges of the dome but I am concerned about exposure in that area to the elements. Will it wick moisture under the dome and lose insulating value? Should it be waterproofed?

Thanks
Reply With Quote
  #2  
Old 07-23-2009, 11:44 AM
Jed Jed is offline
Journeyman
 
Join Date: Apr 2008
Location: Bend, Oregon; West Coast USA
Posts: 428
Default Re: vermiculite/portland and weather

Hey Jnpe,

I can't say I remember any conversation about this question in the past, but here are my two cents on the subject...

The vermiculite / Portland cement mixture is a very porous product. It will absorb water.

It would certainly hold water andwhen it gets wet it will wick the water through the full structure. And if you live where it will freeze, the frozen water will break up the structure created by the Portland cement.

I think if you want your structure to last, you will cover the exposed vermicultie / Portland insulation with tile, or stone or some product that will protect this insulation from the weather and keep it dry.

JED
Reply With Quote
  #3  
Old 07-23-2009, 07:23 PM
dmun's Avatar
Moderator
 
Join Date: Jul 2005
Location: New Jersey USA
Posts: 4,216
Default Re: vermiculite/portland and weather

Those builders who take their vermiculite concrete out to the edge of the support slab usually cover it with whatever surface treatment they use for the stand/structure be it stucco, tile, stone or brick face, etc.

It's not recommended to leave your insulation open to the weather.
__________________
My geodesic oven project:
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
  #4  
Old 07-26-2009, 05:15 AM
Serf
 
Join Date: Jul 2009
Location: Virgina
Posts: 2
Default Re: vermiculite/portland and weather

Thanks for the replies!

Most good thermal insulators by design have a high degree of porosity and just wanted to make sure I wasn’t missing something re. verm./port. Encapsulating the exposed edges with stucco sounds like a reasonable approach and planning to proceed that way.

Found one bag of #8 vermiculite locally and have ordered the remainder.

Thanks Again
Joe
Reply With Quote
  #5  
Old 07-26-2009, 03:18 PM
Apprentice
 
Join Date: Oct 2007
Location: SC usa
Posts: 125
Default Re: vermiculite/portland and weather

Definitely don't leave the vermiculite mixture exposed to the weather! See my post from last year about failed attempt to use it as a roofing material. It will continue to sorb moisture if not weatherproofed... then it will freeze and chip off in small chunks.
__________________
Paradise is where you make it.
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



All times are GMT -7. The time now is 08:50 PM.

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