One of the most serious problems facing the building industry in many countries is the shortage of labor with the attendant es collation of wages. The inability to keep pace with the steadily growing demand for construction work of all kinds (especially housing) is forcing both state and industry to promote the search for new construction methods and improvement of existing ones, with a view to increased building capacity. As a result, there is an urgent need for reliable quantitative data on the comparative labor requirements of the different methods.