Scaffolding and ladders are of bamboo.  Gravel and sand are carried in wooden two-person box carriers to the mixing machine.  The mixed concrete is shoveled into plastic mesh carrying bags slung on a pole between two people, who walk up the bamboo ramp to deliver the concrete to the upper floors where it is being laid.

Just for comparison, here’s a site in Japan (lower right), and one from India (lower left).  The Japanese site is very well screened due to the high density; the Indian one is similar to the Bhutanese except that rough wood poles are used instead of bamboo.

The Bhutan project shown above is construction of a modern five-story concrete building for offices or apartments.  Traditional residential rural construction is rammed earth.  Both types have wooden decorations which are mandated by law in order to provide consistency in new construction with traditional syles. 

Photos below are a traditional farmhouse under construction in the Haa Valley with rammed earth for the walls and a craftsperson painting trim.

As you can see, the painting required by tradition is extremely elaborate and time-consuming to do, but very handsome.

In Kenya, on the Masai Mara, traditional Masai houses are made as below, using sticks and mud which are available on or near the site.  Houses are small and basic.  The Bhutanese farmhouse meets Western ideas of comfort, the Masai house does not.  However it works well for the climate it is designed for, which does not have a cold season, is very dry most of the year, but does have a rainy season. 

Houses are grouped around a courtyard or next to an enclosure which protects the herds.  Being able to build and live in a traditional Masai house is a measure of stature in the community; before building their own house, a Masai couple may live with parents (usually his).  On the left you see a house under construction and to the right, completed.