Vermiculite/Perlite volume loss into concrete?

[kebwi]

Straight forward question...I hope.

Mixed at somewhere between a 1:5 and 1:7 ratio (or whatever you recommend), what is the volume conversion between loose vermiculite/perlite and resulting insulating concrete?

Put another way, how many cubic feet of insulating concrete does, say, a four cubic foot bag of vermiculite/perlite yield?

I just want to know because I'm running a bunch of numbers and need the volume conversion for the calculations. Ballpark figure should suffice.

Thank you very much.

[cynon767]

Re: Vermiculite/Perlite volume loss into concrete?

It seemed to me that the addition of the cement did little to effect the volume of the perlite. I just figured on the volume of perlite as roughly equal to the final perlicrete, and it worked out fine.

[kebwi]

Re: Vermiculite/Perlite volume loss into concrete?

Actually, I wan't implying that adding cement would increase the volume (but I see your point), but rather that soaking, mixing, pouring, and working the perlcrete would compress it...and I have certainly read posts on this forum that suggested such an effect.

So, for you, it resulted in nearly one to one though? Thanks for the input.

Cheers!

[david s]

Re: Vermiculite/Perlite volume loss into concrete?

I've found that perlite reduces in volume more than vermiculite. I think it gets a bit ground up the more you mix it.

[kebwi]

Re: Vermiculite/Perlite volume loss into concrete?

Hmmm, they say perliite is slightly more insulative than vermiculite, but I wonder if that still holds with greater compression after mixing.

[david s]

Re: Vermiculite/Perlite volume loss into concrete?

The insulation value is a whisker better for perlite, but for me it's also slightly more expensive. I prefer to work with vermiculite because it doesn't create dust like perlite does which irritates when inhaled.

[cynon767]

Re: Vermiculite/Perlite volume loss into concrete?

For me, perlite was about $5 cheaper per 4 cu. ft. bag, and if mixed carefully didn't break down much. It was fairly consistent, and although I had to be gentle while mixing to keep the dust level down, it was not too hard to do overall.

[kebwi]

Re: Vermiculite/Perlite volume loss into concrete?

This "poll" hasn't accumulated a lot of response. I'm trying to gauge how far a given volume of vermiculite or perlite might go after it is mixed and poured. Any additional thoughts on the vermcrete/perlcrete volume that results from a given volume of vermiculite or perlite? Try to include your Portland ratio and possibly your grain size in your answer as those might be relevant variables.

I'm asking this because the good sources of this material are somewhat distant for me, so I would like to get the right amount the first time.

Thank you.

[papavino]

Re: Vermiculite/Perlite volume loss into concrete?

I think Jamie pretty much answered the question. The final volume is going to be pretty darned close to what you started out with. The Portland isn't going to cause a noticeable increase in your volume. And as long as you don't go nuts mixing the stuff, it shouldn't break down.

[kebwi]

Re: Vermiculite/Perlite volume loss into concrete?

Okay, I'm sorry I keep misconveying my concern. It isn't that the small amount of Portland increases the volume, it is that soaking and spreading it decreases the volume. The only reason I'm concerned about such an effect is that I distinctly remember reading claims on FB that people got far less 'crete out of their verm/perl than they anticipated.

I wholly admit I cannot dig up the relevant threads now, which significantly weakens my defense. :-)

Don't worry about it, I didn't mean to press it if it isn't a serious issue. I'll just round up by a reasonable degree (25% maybe) and see how it goes.

Cheers!

[david s]

Re: Vermiculite/Perlite volume loss into concrete?

You can compress the stuff when you apply it, but that will reduce its insulation. I've found the perlite breaks down a bit more than vermiculite. The mix will take approximately double the amount of water than an equivalent concrete mix that uses hard aggregate.

[dmun]

Re: Vermiculite/Perlite volume loss into concrete?

It comes in four cubic foot increments: it's not like you can order it by the pound...

[kebwi]

Re: Vermiculite/Perlite volume loss into concrete?

Actually, I got several garbage bags of left over vermiculite for free today. It might have some rockwool mixed in. I hope not too much. This is the right stuff, right (see pic)?

[ThisOldGarageNJ]

Re: Vermiculite/Perlite volume loss into concrete?

It might have some rockwool mixed in (see pic)?

If you think you have rockwool mixed in, maybe you can pour some out in a cardboard box, go thru it with a yard blower,,,from what I have read you dont want any rockwool in there as it can stink when it burns off from the heat... hopefully you can blow out the rockwool and just the heavier vermiculite will stay in the box... and from what I can see in the pic it looks ok
Mark

[kebwi]

Re: Vermiculite/Perlite volume loss into concrete?

Hmmm, does anyone think the vermicrete will get hot enough to burn the rockwool if there is an inch or two of Inswool beneath it (I'm referring to the dome of course), unsure about the hearth).

Likewise, does anyone know if the rockwool is dangerous? When it burns do I not want to be inhaling the stuff that supposedly makes it smell bad?