>Is what you are calling Light-Clay what I would call LECA or Lightweight >Expanded Clay Aggregate. Frank, What people on this list are referring to as "Light Clay" is straw that has been made gooey by mixing it with clay slip. It is then rammed into forms -typically between posts in a post & beam building - and then left to dry. It makes a natural and rather insulative wall material. Thanks anyway, Robert Bolman