Each to their own. Since it will be sunken I hope they plan on putting a drain in somewhere that actually collects water, some are clueless as to what purpose a drain serves, so you don't having standing water for any amount of time or else you will have clay soup.

Here is a link that might be useful: Propagating Perennials

Bullthistle,

It seems like you don't think this is practical? Yes, we will be taking care of the drain issue. But there is a chance that where the steps that leads to the sunken patio, there will be a lot of wash offs.

I know its wacky, but I cannot but hope that I can pull it off.

To be very direct: water is the number one enemy of adobe. If the patio is exposed to water, it will erode quickly, regardless of drainage.

Even if I plaster it with natural plasters?
Thanks in advance

See if you can find somebody local with some sort of experience with building adobe. Maybe somebody at a historic reconstruction? I know there are examples near Phoenix. It will probably be a DIY experiment, and may require more annual maintenance than you really want. But what do I know. We have rock to build patios out of, and if it doesn't work out, I just pull it up and relay it.

I agree with Kim. Adobe is an inappropriate material. What about Saltillo tile?

-Ron-

I guess I am hearing "sunken adobe " as an oxymoron. Not because I am expert in the matter, but because it is totally dependent on your achieving perfect drainage, controlling any other material runoff or drift, and drying out well before use--all typical patio issues, but seem magnified several fold with adobe as other building processes are a bit more forgiving. So how would you accumulate evidence and reassurance that that's likely to be accomplished? Otherwise what you will get is, it's pretty hard to make that work.

When building a wall it is not recommended to use adobe below grade as moisture will weaken the construction. It must be said that the formula for adobe is not fixed in cement and what you want may be closer to a brushed dirt floor. What I think I mean is that moisture may be something you want to encourage although it being sunken may not turn out well. Not a project to offer out.

I have a backyard full of adobe 12x12 pavers. They are all laid on a level sand surface. I would imagine that drainage would be an issue with any sunken patio. I live in Central California so we don't get lots of moisture, but your adobe pavers will not "wash" away. The adobe that was featured on the recent HGTV looks nothing like the authentic pavers that I have seen. Many homes in my area have them. They make for a very informal feel. I am curious as to where you can get adobe pavers? The last adobe plant that I know about on the west coast went out of business a few years ago.

This is a totally doable project.
I've seen many outdoor adobe floors in the various countries that I have traveled to.
I would suggest that you use a binder in your clay mix just like many of the ancient civilizations did.
Several landscape companies offer different types of organic binders.
Some binders are extracted from pine trees and others from agave plants.
You can buy the binder in sack form or already mixed into your adobe/ clay/ sand/ decomposed granite mix.

Several companies sell a premix called " TerraPave".

It wears extremely well. Several large commercial parking lots ( such as HP in Silicon Valley along with a few other green building projects ) have used this
product .

I'm using it, TerraPave, on a residential project in Sonoma county and getting it provided by Wheeler Zameroni Supply in Santa Rosa.