[Cob] Large Gravel-Filled EarthBag Foundations - Off Topic and More!

[Don Jackson]

Ouch!
Re: 
>1.) Seems you've gotten the "I hate concrete" philosophy down, but  
>why?  Because it isn't natural?  Neither are gravel (intensive  
>industrial product) filled bags, nor fiberglass (even more industrial  
>and carbon-emittive) rebar spikes.  Then there's the petro-slurping  
>tractor to do all the heavy lifting.

Because the production of cement is Co2 intensive, because I don't want to be responsible for creating any more concrete garbage (what foundations and other concrete structures become when someone decides a different land use is more useful, instead), and because I don't like the frenzied pace necessary when concrete is poured.  I ran my tractor on pure virgin Canola Oil last summer, despite the fact it's almost new and still under warranty, because I'm trying to engineer fossil fuels out of my life, too.  That still doesn't mean I want to live in the dark ages, and at my age, I'm getting too old to do that much work by hand, unfortunately.  I'd replace the rebar with dried bamboo if it was readily available in this country.

>2.) Do you have any idea how much a one-yard bag of gravel would  
>weigh?  Last I checked a yard of rock weighs 3500 pounds - yep,  
>almost 2 tons.  Doubts any forklift or tractor bucket could lift that  
>without destroying its hydraulics.

Yup.  A yard of 3/4 minus weighs between 2400 pounds (my figures from when I was driving dump truck) and 2800 pounds (what I just read on a web site).  My tractor (the smallest "yellow" one that John Deere makes) will pick up 2000#, so one yard bags couldn't quite be full, or they'd have to be filled in place - no problem, this would still be doable.  I can't break the hydraulics on this tractor, it's built tough enough it just quits lifting when it's overloaded too much, and I think most industrial-type equipment is this tough.  Maybe the little toy farm tractors aren't, but that's not what I'm using.  That's not what commercial off-road forklifts are, either.

>3.) Ever tried spiking anything into compressed rock before?  I doubt  
>a fiberglass rebar would be able to penetrate the rock, and certainly  
>would splinter with dangerous consequences - be sure to wear eye- 
>protection, heavy gloves, coveralls to avoid the flying fiberglass  
>shards.

You might well be right about that, and I haven't tried this, I've only speculated it.  It would be easier to drive stakes into 3/4 minus than into a rubble trench foundation, though, and that was my other thought here.  I'd use a hydraulic post pounder, like farmers and fence builders use, and I'd mount it where the front bucket goes on the tractor, so it could be lifted up as needed.  I hoped to get feedback on this idea, and I appreciate yours.

>4.)  This whole thread is way off-topic for this list - where's the  
>cob here?  Maybe you'll plaster with cob?

I'm sorry if I posted this to the wrong list, but I figured straw bales that were 2' wide would require a similar foundation to cob.  Yes, I'll plaster with cob.  I just bought a plaster pump to help with that, but that's another subject, and I know most of this group isn't especially fond of machinery.  I'm sorry if you found my questions offensive in some way.

I've also seen a lot of the same members over on the organic_architecture group, and I didn't see any reason to ask the same people twice.  I will, though, if this is considered totally off-topic to cob people.  From your response, maybe it is.

I've also heard (off list) that you are one of the most knowledgeable posters here, and I certainly don't want to start off offending you.  I hoped these same ideas would have a great cross-over interest to cob people.  I'm interested in baling up light clay, too.  I know all of these techniques are very similar, and in my ignorance I haven't sorted it out into tiny niches yet.  That's probably my problem as well.  :)



On Feb 14, 2009, at 12:50 PM, Don Jackson wrote:

>
>
> Hi;
>
> I've read about using gravel filled earthbags for foundations.  I'm  
> interested in anchoring 2 foot thick bales to this sort of  
> foundation, using fiberglass rebar pounded through (no concrete  
> bond-beam; I'm trying to engineer the use of cement out of my life).
>
> To make a foundation out of earthbags for a 2' thick wall would  
> require very large earthbags, or a double row of them perhaps (or,  
> run them the other direction, or a criss-cross pattern, etc.?).  In  
> any event, that would require a lot of bags.  I already want to do  
> everything, as much as possible, with my tractor.  It would make my  
> life a lot easier if I could use the giant one yard size bags, that  
> can be moved around with a forklift attachment.  That might easily  
> make enough foundation width, allow for filling and placement with  
> the tractor, and accomplish a big "chunk" of affordable foundation,  
> all in one swift move.
>
> But, I already know the use of earthbag foundations is in the  
> beginnings of acceptance, and I've never heard of anybody using  
> these large bags to make foundations (indeed, everyone else seems  
> to either be using "tubes", or bags that weigh little enough they  
> can be moved by hand).  I have a house that needs remodeled, in a  
> rural area, so I think I can get away building this without permits  
> (after all, how much money am I really putting into this  
> project???).  I still don't want to do anything outright unsafe.   
> Does anybody have any thoughts on using these super-large size bags  
> for foundations, filled with 3/4 minus gravel, if giant bales were  
> anchored to it with industrial-strength fiberglass rebar?  Thanks  
> for your input!
>
> Don





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