Elevator Shaft (aka Hoistway)

[billgilbert]

My visionary wife thinks our new home ought to have provision for an elevator should one be needed in our hillside home, as the garage and hobby rooms are beneath the main level. After researching numerous elevator styles, and the hoistway requirements, I was able to give up some personal closet room as a compromise for a removable floor slab-to-attic 5' X 5' storage room. Special wall bracing is to be added later for the model ultimately chosen.

Most of the construction drawings recommend a slab recess of about 6 to 8" inside the hoistway. This provides a smooth transition to the cab floor. A classic model called the "Elevette", seems ideal if needed and I even found a couple that were salvaged for about $4k, plus freight. Installation extra, but I'll have the power boxes already in place, if ever. . .

My question then is:
How does one make the 5'X5'X8" recess IN THE SLAB? This lower level is Floor ZERO and is a conventional concrete slab. Making "Open Below" is out to daylight and inserting a shape doesn't reach to the walls at the main slab level.
This IS really only a technical detail that can be handled by the concrete contractor, but HD7 seems lacking this unique feature. Did I miss something?