Finish work commences at the beginning, with the steel work. For below ground pools and reservoirs the finish work begins with excavation. A nice smooth work area with no loose dirt makes the job easier and the finished product is therefore better.
The above graphic example illustrates two layers of welded wire. A grid of reinforcing steel bars is between them. Further back is a darker area which depicts an outer layer of metal lath. 1.25 centimeter square welded wire is good on one side. Two layers of poultry netting also serves the purpose. The outer layers hold wet plaster and provide significant strength. These items are obtained from a vendor who supplies masons.
Rebar is sold as #3 (3/8 inch diameter (95mm)), #4 (4/8 inch (114mm), #5, etc.
Reinforcement steel bars are sold in many diameter sizes. 1.15, 1.25 and 1.60 centimeters are approximately standard.
Welded wire is sold in rolls and flats. It is available in almost any measurement and gage. A standard construction size is 15 centimeter squares and 10 gage wire in both directions. Ten gage is 3.6 millimeters. The above graphic example illustrate proper position of the squares; the layers are positioned to create 7.5 centimeter squares.
This website recommends plain or stainless steel welded wire. For sizes other than the usual 6,6,10,10, go to this web site (The small welded wire category is also listed as "wire cloth" and "hardware cloth"). Use "welded wire" or "wire mesh" to search the web. Forces concentrate at surfaces. Choose quality welded wire for important work.
The cement portion of ferrocement is standard cement. It is sold in bags or barrels. The mix ratio is three dry measures of sand and one dry measure of cement, with quality cement. Quality plaster makes a sharp sound when dropped on a hard surface. Poor plaster yields a dull thud, like soft sand stone. Do not apply plaster to valuable work without a fully cured test sample. The human ear can easily discern a hard sounding click from a soft sounding thud, no education is required.
Combine the two examples above to construct a reservoir. The online guide for building a water tank is reached here, this web manual contains complete instructions for building a reservoir and many techniques useful to general construction and sculpture. Printed field manuals for water, sculpture, understanding biological fiber, sanitation, house construction and self-sheltering concepts are available for purchase here.
The example aquaculture reservoir is one meter deep and above ground. It would be constructed like the example at the top of this page with approximately twice as much steel in the bottom bend. Ferrocement gains strength from angles and curves. The illustrated wall is strengthened with bends and gussets. To lengthen this wall, extend every third, or fourth gusset to the ground.
Plumbing holes are made with a piece of pipe in the hole location. Spin the pipe and remove it when the plaster is hard enough for finish work. Use standard compression plumbing fittings with gaskets to secure pipe through the holes. Read more about this in the reservoir construction manual.
The wall illustrated is thicker than required for strength because a smooth wall has more plaster on it than a wall that is built only for strength. This concept is clearly illustrated by the reservoir below (60 meters cubed). Total thickness where the squares are visible is 4 centimeters maximum. This reservoir has been full of water since 1970 (photo taken in 2001, similar structures were inspected in 2006). No problems.