The Potala was undergoing considerable renovation when we visited. The techniques, labor force, and materials seemed predominantly Tibetan as far as I could tell.
The most extensive work--I don't know to what extent it was refurbishment, and to what extent it was outright reconstruction--was being done on the smaller buildings, on the low ground at the front of the main Potala Palace.
Working on the top of a wall
Using sticks with flat weights mounted on their ends, Tibetan workers pounded some composition (clay and something?), compacting it to make a watertight roof.
Groups of them turned this into a sort of dance, done in lines, stepping in unison and chanting as they pounded.
There was also renovation occurring on the top levels of the Potala.
Additional photos that essentially duplicate the ones above
The Potala, Seen from Below
Copyright © 2005, Edwin E. Moïse. Revised June 24, 2005.