[Illustration]
Underground cisterns are useless if they leak. In dry weather they
are empty, and at other times the ground water seeps in and makes the
“soft” water as “hard” as that from the well. Concrete cisterns have no
joints to leak: they are built in one solid piece.
In placing the cistern, select a site convenient to the principal
down-spout and the kitchen. Do not forget to make allowance for 8-inch
walls in laying out the plan. If the ground in which the pit is dug
is sufficiently firm to stand alone, no outside form will be needed.
Otherwise the hole must be dug large enough to receive an outside form
built similar to the inside one. Make the inside form of 1-inch boards
on 2 by 4-inch studding so that the siding will be toward the earth
walls. Mix the concrete 1: 2: 4 and lay a 6-inch floor on the earth
bottom. Immediately set the wall forms on all sides. In filling the
wall space, be careful not to shovel the concrete against the earthen
wall: dirt in concrete is liable to make a leaky wall.
[Illustration]
After the concrete side walls have been brought to ground level, set
a 5-inch board on edge around the outside of the cistern, so as to
hold the concrete for the platform. Saw off the uprights of the inside
form 6 inches below the finished top of the concrete cover, and nail
2 by 4-inch floor joists even with their tops. Floor the joists with
1-inch boards. Braces, to keep the wooden platform from sagging, may
be placed down the middle of the cistern as shown in the drawing. To
provide for a manhole opening, build a bottomless box 5 inches deep,
2 feet square at the top and 18 inches square at the bottom—outside
measurements,—or have the tinsmith make a round bottomless tin form 5
inches deep, 2 feet in diameter at the top and 18 inches at the bottom,
just like a large dishpan without a bottom.
Begin at one side of the platform, tamp in 1½ inches of concrete, and
upon it lay heavy woven wire fencing. Allow the edges of the wire to
extend within 1 inch of the outside lines of the platform. Bring the
platform to its full thickness by immediately placing the remaining
3½ inches of concrete. Work rapidly and do not stop for any reason
until the cistern cover is completed. As the work progresses, finish
the surface with a wooden float. Grease the manhole frame and place it
where the opening is desired. Strengthen the floor around the manhole
opening by laying four short ½-inch iron rods, placed criss-cross, 2
inches from the bottom of the slab and the same distance back from
the edges of the hole. If the tin form is used, the manhole cover may
be cast at the same time as the remainder of the floor. Reinforce
the cover with woven wire and also with four short lengths of ½-inch
rods laid in the form of a square. Have on hand an old bridle bit or
hitching post ring, which will serve as a lifting-ring for the concrete
cover. In placing the ring in position, provide it with a knob of
twisted wire, or with a nut and large washer, to fix it firmly in the
concrete. If the wooden manhole form is used, carefully remove it after
5 hours. After 3 days build the manhole cover the same as for the tin
form, with this important exception—place heavy paper, cardboard or
leather around the edge of the opening to prevent the fresh concrete
of the cover from sticking to it. Set bolts for a pump base according
to directions given for GASOLINE ENGINE BASES, pp. 87, 88. The
necessary openings for down spouts and for removing water may be made
by embedding tile, of the proper diameter and length, in the concrete
platform or side walls.
When the platform is two weeks old, remove the manhole cover, bore a
hole in the wooden floor, saw an opening, descend and loosen the roof
form, passing it out through the manhole.
[Illustration]
If the cistern water is to be used for cooking and drinking, provide
a filter on the outside of the cistern wall. Construct the filter
similar to the cistern, of dimensions 4 by 3 feet and 4 feet deep.
While building the cistern wall, lay an 8-inch tile through it, at the
proper height to connect with an opening of the same size in the filter
wall at its floor, and place a removable screen of ¼-inch mesh over the
opening. Fill in 2 feet of coarse charcoal. Cover the charcoal with 1
foot of sand and gravel. Lead the water from the roof into the top of
the filter. Cover the filter with a loose concrete slab.
Four men built a cistern 8 feet square and 8 feet deep, with a 6-inch
floor and a 5-inch platform, in two days. The cistern holds 122 barrels
of 31½ gallons.
=Materials Required=
Screened gravel or crushed rock 8 cubic yards at $1.10 $8.80
Sand 4 cubic yards at $1.00 4.00
Portland cement 13 barrels at $2.50 32.50
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$45.30
“Soft” water is not only better for the bath, but also makes the
washing easier and the clothes whiter. Mischievous children cannot
remove concrete manhole covers.