#31  
Old 10-18-2011, 06:45 AM
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Default Re: Crumbly Vermiculite/Portland Cement

Can anyone suggest filling in between steel studs with this mixture or should we use loose vermiculite or a good high heat insulation on a roll ? I see a lot of options.
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  #32  
Old 10-18-2011, 10:59 AM
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Default Re: Crumbly Vermiculite/Portland Cement

You can fill in the enclosure space with the 12:1 mixture. Some have done this to prevent the loose vermiculite from sifting out of small openings. Make sure your enclosure is well ventilated.
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  #33  
Old 10-23-2011, 05:49 AM
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Default Re: Crumbly Vermiculite/Portland Cement

is there any aggregate that can be added to the perlite and cement to help with binding and strength
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  #34  
Old 10-24-2011, 12:38 PM
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Default Re: Crumbly Vermiculite/Portland Cement

Yes, simply add sand, that will increase its strength, but if you double it's strength you halve it's insulating capacity.
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  #35  
Old 10-24-2011, 07:22 PM
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Default Re: Crumbly Vermiculite/Portland Cement

Neil2 I did a test and found that 5 to 1 worked best with my vermiculite (size of rice grains) and mortar mix concrete. Any less concrete was not holding it to the outside wall. Can you tell me why this is important ,,,,, Make sure your enclosure is well ventilated ?
Thank you.
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  #36  
Old 10-25-2011, 03:10 AM
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Default Re: Crumbly Vermiculite/Portland Cement

[IMG][/IMG] if you look at the pics in the link you will see that vemiculite mix at a a ratio of 5 to 1 with A-type cement (portland cement) works well and has plenty of strengh as a insulation coat. the pic shows it rended to the done 5 inches thick.
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  #37  
Old 10-25-2011, 03:22 AM
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Default Re: Crumbly Vermiculite/Portland Cement

Adding a 5:1 vermicrete on the outside of the dome is way too rich IMO. A 10:1 mix is adding as much mass in cement as vermiculite. A 5:1 mix is adding double the mass of cement to vermiculite with the result that you are halving the insulating value. You only need the stuff to stand up vertically on its own because you add a render /stucco layer over it anyway. You do need a 5:1 vermicrete under the floor because it needs the strength there. Everyone thinks that a weak vermicrete ,over the dome, will not possibly harden and have sufficient strength, but it does..
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  #38  
Old 10-25-2011, 06:04 AM
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Default Re: Crumbly Vermiculite/Portland Cement

Quote:
Originally Posted by david s View Post
Adding a 5:1 vermicrete on the outside of the dome is way too rich IMO. A 10:1 mix is adding as much mass in cement as vermiculite. A 5:1 mix is adding double the mass of cement to vermiculite with the result that you are halving the insulating value. You only need the stuff to stand up vertically on its own because you add a render /stucco layer over it anyway. You do need a 5:1 vermicrete under the floor because it needs the strength there. Everyone thinks that a weak vermicrete ,over the dome, will not possibly harden and have sufficient strength, but it does..
I used 11:1 mix of perlite around my inner arch thermal break and it worked well.

Chip
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  #39  
Old 10-25-2011, 06:36 AM
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Default Re: Crumbly Vermiculite/Portland Cement

thank you for the valuable info., just starting the layer this week. Will try the 11 ;1 ratio. Is the stucco mix you prefer in buckets (premixed) or dry or is it regular concrete ?
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Old 10-30-2011, 01:47 PM
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Lightbulb Re: Crumbly Vermiculite/Portland Cement

Good Afternoon Mates !

Got the first 3 inches of mud on the walls, roof and back (Vermiculite/Portland Cement) this weekend. Found that 8 to 1 worked best for me. I think my vermiculite was fairly large pellets and required a bit more cement to hold together. A few Questions I hope you can help with:
1. How long would you guess this insulation should dry out before adding another layer? It's tarped, loosley and about 50 degrees F outside. Guessing a week.
2. I read a few things about the top layer of "stucco" to seal the insulation. Is this ordinary mortar mix ?

I am using green board over my steel frame on sides and a recyled tin roof ! The back is open and will have mesh reinforcement to help hold mortar.

thank you in advance for your valuable tips!
Chef
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