Area Build Type 
This property specifies when area instance versions of the area should be built automatically using the area constructor that is implemented in the area constructor class.
Possible values are:
No Autostart
Area instance versions are not built automatically. The basic property automatic area building must not be activated with this setting.
Autostart for Read Request
A new area instance version is built automatically if there is a read access and no active area instance version is available. The basic property automatic area building must be activated.
Autostart for Read Request and Every Invalidation
Automatic area building as is the case with Autostart for Read Request, and additionally with read access of a displaced or expired area instance version. The basic property automatic area building must be activated.