Too much clay - how can I modify it?

Without importing a ton of sand, rock or fiber, is it possible to easily modify a soil that has too much clay (soil here is practically 100% clay and very expansive - it is just short of bentonite). I am constructing a post and beam house and would love to use earth-bags as thermal mass in-fill. But between the labor of tamping bags, and the fact we have limited sand/fiber to modify the clay, I am reluctant to use the soil in any structural way, or even as wall infill (as the walls will have to support the windows and doors to some extent.
Any ideas for a low labor, low cost way to earthbag this soil (picture pottery clay with LESS sand granules than usual in it)

Jj Grey wrote:Without importing a ton of sand, rock or fiber, is it possible to easily modify a soil that has too much clay (soil here is practically 100% clay and very expansive - it is just short of bentonite). I am constructing a post and beam house and would love to use earth-bags as thermal mass in-fill. But between the labor of tamping bags, and the fact we have limited sand/fiber to modify the clay, I am reluctant to use the soil in any structural way, or even as wall infill (as the walls will have to support the windows and doors to some extent.
Any ideas for a low labor, low cost way to earthbag this soil (picture pottery clay with LESS sand granules than usual in it)

Unmodified clay as fill for earthbags is not a good idea, as you know. Typically no more than about 30% clay is possible, with the rest being sand.

My suggestion would be to infill between your posts with earthbags filled with an insulating material, such as rice hulls, perlite, or crushed volcanic stone. Then incorporate some thermal mass into the structure with an earthen plaster or in your floor or stove surround.

Kelly Hart wrote:

Jj Grey wrote:Without importing a ton of sand, rock or fiber, is it possible to easily modify a soil that has too much clay (soil here is practically 100% clay and very expansive - it is just short of bentonite). I am constructing a post and beam house and would love to use earth-bags as thermal mass in-fill. But between the labor of tamping bags, and the fact we have limited sand/fiber to modify the clay, I am reluctant to use the soil in any structural way, or even as wall infill (as the walls will have to support the windows and doors to some extent.
Any ideas for a low labor, low cost way to earthbag this soil (picture pottery clay with LESS sand granules than usual in it)

Unmodified clay as fill for earthbags is not a good idea, as you know. Typically no more than about 30% clay is possible, with the rest being sand.

My suggestion would be to infill between your posts with earthbags filled with an insulating material, such as rice hulls, perlite, or crushed volcanic stone. Then incorporate some thermal mass into the structure with an earthen plaster or in your floor or stove surround.

At that point, (infilling with insulating material in earth-bags) it is not much different financially than just buying fiberglass insulation to fill the voids in the walls. I guess it is buying tons of sand or buying fiberglass insulation then.

Jj Grey wrote:

Kelly Hart wrote:

Jj Grey wrote:Without importing a ton of sand, rock or fiber, is it possible to easily modify a soil that has too much clay (soil here is practically 100% clay and very expansive - it is just short of bentonite). I am constructing a post and beam house and would love to use earth-bags as thermal mass in-fill. But between the labor of tamping bags, and the fact we have limited sand/fiber to modify the clay, I am reluctant to use the soil in any structural way, or even as wall infill (as the walls will have to support the windows and doors to some extent.
Any ideas for a low labor, low cost way to earthbag this soil (picture pottery clay with LESS sand granules than usual in it)

Unmodified clay as fill for earthbags is not a good idea, as you know. Typically no more than about 30% clay is possible, with the rest being sand.

My suggestion would be to infill between your posts with earthbags filled with an insulating material, such as rice hulls, perlite, or crushed volcanic stone. Then incorporate some thermal mass into the structure with an earthen plaster or in your floor or stove surround.

At that point, (infilling with insulating material in earth-bags) it is not much different financially than just buying fiberglass insulation to fill the voids in the walls. I guess it is buying tons of sand or buying fiberglass insulation then.

Tons of sand won't give you any insulation. Fiberglass insulation will need walls built on both sides to cover it. Earthbags filled with insulating materials can be plastered directly and they may be able to support framed windows.

Kelly Hart wrote:

Jj Grey wrote:

Kelly Hart wrote:

Jj Grey wrote:Without importing a ton of sand, rock or fiber, is it possible to easily modify a soil that has too much clay (soil here is practically 100% clay and very expansive - it is just short of bentonite). I am constructing a post and beam house and would love to use earth-bags as thermal mass in-fill. But between the labor of tamping bags, and the fact we have limited sand/fiber to modify the clay, I am reluctant to use the soil in any structural way, or even as wall infill (as the walls will have to support the windows and doors to some extent.
Any ideas for a low labor, low cost way to earthbag this soil (picture pottery clay with LESS sand granules than usual in it)

Unmodified clay as fill for earthbags is not a good idea, as you know. Typically no more than about 30% clay is possible, with the rest being sand.

My suggestion would be to infill between your posts with earthbags filled with an insulating material, such as rice hulls, perlite, or crushed volcanic stone. Then incorporate some thermal mass into the structure with an earthen plaster or in your floor or stove surround.

At that point, (infilling with insulating material in earth-bags) it is not much different financially than just buying fiberglass insulation to fill the voids in the walls. I guess it is buying tons of sand or buying fiberglass insulation then.

Tons of sand won't give you any insulation. Fiberglass insulation will need walls built on both sides to cover it. Earthbags filled with insulating materials can be plastered directly and they may be able to support framed windows.

Oh, I have about 100+ sheets of lightly use Styrofoam insulation panels (2 and 4 inches thick - a free for pickup deal). mostly not suitable for _inside_ a house (too dirty) but excellent for outside walls just under whatever plaster or siding is being used, I want the thermal mass so I can let the fire go out when it is 40 below and come back from a couple day long trip without having my pipes frozen solid. Insulation works great - but it doesn't keep enough heat when it is negative 40 below for weeks at a time, you need thermal mass AND insulation. So the bags themselves don't need to insulate, just hold thermal mass instead.

Highly expansive clay will be useless for your project.
I have been involved with about 500 earth block houses.
You will be advised to make test bricks with a range of different naturally occuring soils, and watching them dry out and crack.
You will eventually find a good soil or a good mix.
Mixes are harder for obvious reasons. Importing suitable soil may be you only way to get a result.
But remember, you often only have to move a 100 metres to find better soils for earth blocks.

Given the available material...adobe?

Mix any kind of manure and grain hull or straw in with the clay, cure and turn it for a week,  make some test bricks and dry them slooooowly. Presto: thermal mass.

That's what all the local houses are built with here.

John C Daley wrote:Nighly expansive clay will be useless for your project.
I have beeb invl\olved with about 500 earth b;ock houses.
You will be advised to make test bricks witha range of different naturally occuring soils, and watching them drt out and crack.
You will eventually find a good soil or a good mix.
Mixes are harder for obvious reasons. Importing suitable soil may be you only way to get a result.
But remember, you often only have to move a 100 metres to find better soils for earth blocks.

I've dug test holes all over the 40 acre parcel (that is about 1/4 mile on a side) and it is very consistently clay or gravel and clay below what is clearly either silt or organic hummus.  The whole county is about the same. The only variation are minor seams of black pre - lignite coal like substance (also fairly organic and fairly thin).

Nathanael Szobody wrote:Given the available material...adobe?

Mix any kind of manure and grain hull or straw in with the clay, cure and turn it for a week,  make some test bricks and dry them slooooowly. Presto: thermal mass.

That's what all the local houses are built with here.

I suppose I can buy some straw (or harvest my own local grasses come fall) and try for some test bricks. Bricks might also fit inbetween the walls better than bags.

If you have a saw mill near by you might want to try saw dust they usually give it away.

You may find each hole has different clay, sand mixes and one may be ok.
You need a roughly 50/50 clay and sand, but not highly expansive clay, it will crack as it dries.

Excuse my ignorance, but wouldn't gravel work?

Clay doesn't crack if its not wet when you make the blocks.  



I've seen these machines work and they are simply amazing.  Vermeer has a non-profit arm of their company that invested a ton of money into research and development on this machine.  They offer then almost at cost to people working in the developing world.  The blocks are simply compressed earth, but are so hard, they retain their shape and hardness even when submerged in water for a couple of days.  The compression is about a zillion PSI.

In compressed blocks like this, you want less than 10% moisture, and the higher the % of clay, the stronger the block.

My press and the Cinva Ram are similar but different.
There is Cinva Ram stuff on You tube.
Gravel is no good because earth blocks rely on the osmosis that takes place between soil particles
sand, clay and all of different particle sizes.
Gravel does not have enough fines within the mix