Most Cost effective and fast earthen floor option for a large area.

What is the most cost effective and fast earthen floor option for a large area? To be more specific, a 30 ft by 90 foot pole barn at the bottom of a large hill. It has a lot of drainage that comes from downhill, and we have been considering options for living in it, or rolling something into it to live in it. Currently it has a dirt floor that often gets wet and muddy. Floor is the first consideration no matter what we end up doing. You should know that much concrete is ridiculous in price, even that much wood for a raised deck is crazy. So the next option is ways to make the dirt solid, hard, and waterproof.

First consideration is earth/linseed options, however that seems like it would not go well for this much area.

So next moved onto dirt-polymer options. Dirt-glue.


https://globalenvironmentalsolutions.com
https://en.wikipedia.org/wiki/Polymer_soil_stabilization

Another consideration is making concrete with cheaper materials like wood or even dirt. Earth-crete and Arbolite. However even those options only reduce the price of concrete, it is still quite a cost.



What are your options and opinions? We live in an area with a lot of sandstone and a lot of water. Clay is minimal, and slate is even less. Tell me what you think.

"[The floor] has a lot of [topsoil] that comes from [water running] down [the] hill...."

Sounds like you need to resolve the issue of water and topsoil running down the hill before you attend to fixing your barn floor.

Amy Gardener wrote:"[The floor] has a lot of [topsoil] that comes from [water running] down [the] hill...."

Sounds like you need to resolve the issue of water and topsoil running down the hill before you attend to fixing your barn floor.

There is an old French drain on the side that faces the hill, however it has aged and needs to be dug up and cleaned out or replaced.

Hopefully, that French drain will is on the 30' side of the barn and your sandy soil will be easy to dig and provide nice percolation for you. Sounds like fixing that drainage will be a lot less toxic and expensive than sealing the barn floor at this time. You will have more options for your space in the future if you don't have to commit to finishing the floor so early in your design process. Best wishes on the adventure of creating your new living space, Joshua.

I would trench around the barn and back fill with a cheap weeping tile tube and pea gravel. Then regrade around the shop as well as possible.
The barn floor could be covered with heavy poly and tanked up the sides by 6". Then back fill the inside with gravel and sand or driveway crush.  
In a living space I would then recover the gravel with poly and build a 2x6 floor with 3/4" ply over top.