Instructions For Erecting Tanks
To insure a long lived and structurally safe tank, a properly designed foundation is essential.
The entire weight of the tank and contents must be borne through the bottom; the load being transferred to the foundation by means of chime joists.
There are 4 general types of foundations for tanks; redwood mudsills, concrete pier walls, pier blocks, and concrete slabs. Generally, a concrete foundation is best and should be used for all permanent installations. Whichever type is used, it should have sufficient bearing area on the ground to properly distribute the load and provide air circulation under the tank. Ground loading of 1 ½ tons per square foot is recommended. For loads heavier than this, the bearing capacity of the soil should be tested. Where freezing temperatures are likely to occur, the foundation should extend below the frost line.
Chime joists should be large enough to provide a minimum of 2" clearance below the staves to allow for free circulation of air. Do not allow the weight of the tank to be borne by the staves.
Figure 1
(a) Set chime joists in place on the foundation. Space as noted on chime joists.
(b) Starting at the center, set the bottom pieces in place, using the dowels provided to fasten the pieces together. Arrange the bottom pieces at right angles to the joists with the numbers and letters up. The 3 or 4 center pieces should be placed tightly together while the remaining pieces should be spread evenly to increase the bottom diameter 3/32" for each foot of tank diameter.
(c) Tack lath across the bottom to hold the pieces in position. Do not nail the bottom boards to the chime joists or to the foundation.
(d) Set the 1st stave in position so that the center of the stave is at the point between 2 bottom pieces in the middle. Drive the stave halfway on to the bottom circumference, using a block of wood between the stave and hammer. Be certain the edges are vertical and that the top just leans outward. (Check with plumb line or spirit level.)
(e) Brace the stave in this position.
Figure 2
Set up the rest of the staves in the same manner, holding them in place with a rope or by tacking lath to each stave, allowing the strips to overlap. Use additional bracing as required.
Check each stave to be sure it is vertical and that the staves are driven as close together as possible at the bottom. The bilge staves (marked with hoop spacing) should be distributed equally around the tank. If the staves fit too tightly, take a light shaving off the edge of the bottom with a hand plane. Arrange the staves so that the joints between them do not coincide with the joints between the bottom pieces. Provide support for the bottom cant (curved) end pieces so that they do not sag. Save the narrow staves until last, since one of them may exactly fit the last opening. Before putting the last staves in place, remove the lath holding the bottom pieces and clear out the tank, being sure there is nothing caught between the bottom joints. If the last stave is too wide, it may be fitted (measure carefully at the bottom) by ripping or planing, maintaining the proper bevel on the edge.
To install the hoops, drive nails in the bilge staves at the hoop spacing marks to support the hoops until they are tightened. Place the lowest hoop first (using largest diameter furnished) with the threaded end to the left. Continue working from the bottom up. The lugs should span 2 staves. The 2nd hoop should be placed with the lug about 3 feet to the right of the 1st one. The remaining hoops should be placed with the lugs spaced 3 staves to the left (tanks that are 10' or larger in diameter, space at 4 or 5 stave joints) for each succeeding hoop.
When all the hoops are in place, tighten each lug lightly and evenly. At this point, the inside bracing should be removed. Use a block of wood and hammer or mallet to round out the tank by driving the staves in or out until staves are even and the outside surface of the tank is smooth.
After the tank has been rounded, drive the staves on to the bottom with a block held close above the bottom hoop. Begin at the first stave set, and work one quarter (¼) of the way around the tank in both directions; then start at the opposite end of the center plank and drive the second half in the same manner. Do not strike staves with hammer; use a wood block as a cushion. Hoops should be tightened as driving progresses, working from bottom hoop upward. Keep tension on hoops uniform. Special care should be taken with the 2 bottom hoops to see that they are firmly set.
Fill the tank with water as soon as possible after erection to prevent shrinkage and consequent re-tightening of hoops.
Figure 3
Instructions For Installing Register On Tank
(a) Nail brackets to staves flush at top, bottom and uniformly between.
(b) Nail register board to brackets so that the top is flush with the bracket.
(c) Attach metal target (indicator) to board.
(d) Nail pulley board on top of stave so that the cord hole clears the face of the register board.
(e) Thread stainless steel cable through pulleys and fasten by crimping the stainless steel cable sleeve on one end to target (indicator) and adjust the float, so that when the float is on the bottom, the target (indicator) is at the top. Then crimp the cable on the float end.
Instructions For Removing Tannin Stain (Coloring) From New Redwood Tanks
Fill the tank with water and add 2 pounds of Soda Ash (available at chemical, pool, and home improvement centers) for each 1,000 gallons in solution. Thoroughly dissolve the Soda Ash before introducing it in the tank. Let the treated water stand in the tank approximately 48 to 72 hours, then drain out and rinse. The tank is ready to use. Do not use the treated water.
Maintenance and Painting
Maintain the tank water level near the top at all times. Repair leak(s) as it/they appear. Annually or more often (water quality will dictate) empty the tank and rinse out all foreign debris (soil, sand, leaves, etc.).
It is not necessary to apply any kind of a protective coating to a redwood tank; however, the tank may be painted on the outside with a quality boiled linseed oil cut with turpentine (50%-50% or 40%-60%) for appearance sake and to preserve the hoops.
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