80 Protec ting Communit y Water
Howbctnobmxnacbke a cover slab for a well
Once a well has been lined, the next step is fitting a concrete cover slab. The cover
helps prevent polluted wastewater or objects from falling into the well. It also
makes the well safer for children and provides a clean place to
put buckets as people collect water.
Tools you need: shovel, metal saw, blocks of wood, bucket,
rope
➊ The cover should fit neatly over the upper well lining.
Clear a flat place to pour a concrete slab and mark out a circle
the size of the cover slab to fit the well. Place a ring of bricks
around the marked circle. This ring is the slab mold.
Make a mold
for the slab.
➋ Leave a hole in the slab to pass a bucket through or to fit a
pump. The size of the hole depends on the kind of bucket
or pump used, but generally the hole should be large
enough for a 10 liter bucket. A tin drum big enough for a
bucket to pass through can be used to form the hole.
➌ Place reinforcing wire (3 mm) within the slab mold to form
a grid, with spaces 10 cm apart.
➍ Remove the reinforcing wire grid and make a concrete
Place reinforcing wire
and a mold for the hole.
mix of 3 parts gravel, 2 parts washed river sand, and
1 part cement. If gravel is not available, use 4 parts washed river sand
and 1 part cement. Pour concrete in the mold, halfway to the top.
Place the wire grid on top of the wet concrete.
Add the remaining concrete and level it with a piece of wood.
➎ Let the slab cure for 1 hour. Remove the tin drum mold, and
fill the central hole with wet sand. Replace the mold on top
of the sand and place a ring of bricks around it, leaving 75
mm of space between the bricks and the mold. Fill the space
between the bricks and the mold with concrete and let it
Pour the concrete
slab and form the
protective collar.
cure for an hour. After an hour, remove the bricks and the
tin mold and shape the protective collar. For the
collar to give the best protection, a tin cover
should fit snugly over it.
➏ Let the slab harden overnight and cure for at
least 5 days, keeping it wet the entire time.
Shape the protective collar.
Before putting the slab on a well, test its
strength. After it has cured for 7 days or so,
place 4 blocks of wood 1 or 2 inches high under the 4 sides of
the slab to raise it off the ground. Then dance on it! A well-
made slab will not break even with several people dancing on
it. Place a bed of cement mortar on the top of the well lining
and carefully set the well cover in place.
Set the well cover in place.
A Community Guide to Environmental Health 2012