Filling earthbags with crushed stone.

Hello Kelly Hart,

Do you have any experience using crushed stone with earthbags? I live in a town with a large limestone quarry and heavy clay soil. I'd rather use the crushed stone than the heavy clay. Can you point me to some resources that might help me use crushed stone with earthbags.

Also, I can obtain crushed granite for a very cheap price too. Do you think there would be a marked difference between the types of stones using this construction technique.

Thanks for your time and consideration.

Andrew Cegielski
Waukesha, WI

If you use crushed rock you will not have the bags go hard and stable.
The clay within the soil, is what reacts to moisture and then causes the whole mass to harden up.
If you use crushed rock you will always have loose stones within the bags.
If the bags break they will allow to stones to fall out.
You need to think about what you are trying to achieve.

Crushed run is often used as a roadbase that will compact flat and hard without any cement.
If the OP has such matirial he might be able to get good results.
Seems like the quarry would know.

Pertinent content from Kelly Harts website in quotes below



"Q: Fellow Arkansans, Paul and Lisa Majors, filled their earthbags with 100% crushed lime and claim that when cured it's like concrete. What kind of fill, and in what proportions, would you recommend to support heavy loads?

A: Crushed lime seemed to work great for the Majors, and it would for you too if it is available at a good price. Any solid fill material like the lime or soil with a percentage of clay in it should be quite solid enough. But really practically any kind of fill can be used and still find a way to attach things to the wall."








"Q: I'm trying to build an earth bag dome here in Merida, Yucatan. The soil is pretty bare and mostly composed of limestone mother rock. There is an abundance of limestone dust that is not very expensive here and that I would like to use for bag filling, instead of the cement, lime, red earth, stone dust mix that my neighbours are using to build their earth dome house. My plan is for a 5 meter diameter dome. simple. Is their anything I could add to the limestone dust/gravel to stabilize it?

A: My guess is that if you just add enough water to dampen the limestone dust and then tamp it well in the bags that it will pack into a rather solid block. You might try this and see. If it doesn't "set up" after it dries, then you will need to add some cement or perhaps clay to it. I think you are going to have to experiment with a variety of mixes to see what works."

I guess going back to the original comment.
Are you using crushed rock which is usuallysourced from igneous rocks and is hard, or crushed limestone which is a completely different material, and may be suitable.
Pleae clarify which you have in mind.
PS I am a road builder, which is why I focused on 'crushed rock'

I building to two different locations. In Southeastern Wisconsin I can get cheap limestone. In Central Wisconsin I can get crushed granite.

John C Daley wrote:I guess going back to the original comment.
Are you using crushed rock which is usuallysourced from igneous rocks and is hard, or crushed limestone which is a completely different material, and may be suitable.
Pleae clarify which you have in mind.
PS I am a road builder, which is why I focused on 'crushed rock'

I have never used limestone, but it seems you should be ok, I believe crushed granite will have the same properties as igneous rock, no biding fines included and may be hopeless for the task.

My understanding is that in earthbag buildings, the bags should not be relied on to hold the entire load for the long term. The material inside the bag is supposed to bond with itself and dry into a piece like a blobby adobe brick, so that it's more like cob molded in bags. If you use crushed rock that will not bond with itself, then you are depending on the strength of the bag to hold the material in forever. If one bag springs a leak, the material can flow out and the wall collapses. If there's much load, the lower bags might split, I think...

But I've never been involved with earth bag construction so I may have it wrong. I have 25 years experience being closely involved with rammed earth, adobe, and cob building, and with experiments with mixing in random (sometimes silly or ineffective) materials.