Q.: I am seeking information on reinforced concrete construction for a thin-shell one-story house, complete section dome type. It will be curved around a court and have windows facing south for passive solar. The other sides are to be earth berm including some of the roof. Pipe framework will be used to insure stability. Are there methods of applying concrete, or special mixtures, that would be strong and waterproof enough for my purpose? (I am aware of the need for insulation and vapor barriers.) I've seen some work locally using shotcrete. Would it be possible to do the job by plastering if in a location where shotcrete were not available?
A.: Shotcrete is generally useful in producing high strength concrete of low permeability to conform to any shape of curve and if available, shotcrete should be a good choice. If shotcrete is not available, you might consider ferrocement, which is "a composite hydraulic structural material comprising thin sections of cement mortar reinforced by a number of very closely spaced layers of steel wire mesh" ("Cement and Concrete Terminology," American Concrete Institute Special Publication SP-19 ).
An overview of this material and methods of use are given in "Ferrocement in Construction," published in our March 1981 issue, page 269. Several good references are listed at the end of the article. The International Ferrocement Information Center in Thailand publishes a regular journal on ferrocement, with an emphasis on uses for shelter, agriculture and boats and ships. The address is: Asian Institute of Technology, Box 2754, Bangkok, Thailand (phone 5168311-5).