[ExSoldier]

I don't know if gunite is the exact material. They call it (IIRC) SHOTCRETE. It sprays on with a thick widemouth hose directly onto rebar covered with a waterproof sheeting. Then another coat of the waterproofing is applied.... I think gunite is the material used in this structure that also interests me but it is somewhat higher maintenance. Here is a good example of a monolithic dome home.

[DelaWhere]

For gunite, they mix dry portland cement with sand and gravel in the proper oroportions, then meter it through a hose with high pressure air. When it reaches the nozzle, they mix it with water. Shotcrete I believe may be shot wet. That means that you have to shoot the whole batch pretty quickly before it sets up.

The shooting is under pressure and makes it a much denser product and it is harder. If you seal that from moisture, it will last many generations.

Was wondering what they were using for insulation as the R value is fairly low for dense cement.

That process has been used for both swimming pools and for ship building. (there are quite a few ferrocement ships out there.) I have seen very large swimming pools lifted out of the ground by flooding - they come out of the soil all in one piece and have been known to float away.