Carry out the work of P.C.C. bed and provide a cement
mix 1:4 base coat, with water-proofing compound in the required proportion and
above this fix rough Shahabad tiles of size 60 cm x 60 cm (2’0” x 2’0”) or 60
cm x 90 cm (2’0” x 3’0”) with a minimum required width of joint between the two
tiles.
Ensure that all the four sides of the Shahabad tiles
are cut manually to retain a fairly straight edge. Also, check the thickness of
the Shahabad tiles. It should be between 32 mm to 40 mm (1 1”/4 to 1 1”/2).
Maintain the break joint pattern while fixing the
Shahabad tiles for base.
After fixing the Shahabad tiles, grout the joints with
cement slurry completely.
Seal the joints between the Shahabad tiles with the
help of C.M. 1:3. Add some 15 mm metal to this mortar, for enhanced strength
and less shrinkage.
Over this, apply a jointless layer of C.M. 1:3,
approx. 25mm thick and cure it properly for 7 days. This layer provides a
smooth has for the raft and protects the Shahabad base from the movement of
labour and steel bars laid for raft.
Generally, all the conduiting and piping in completed
before casting of the raft slab.
For basement, provision of sump is made in
P.C.C., itself and Shahabad base is also prepared in the same fashion.
Over the plastered Shahabad base, raft slab is cast
and the R.C.C. pardies are erected.
Rough Shahabad tiles are then fixed to the vertical
pardi from outside. Apply neat cement paste on the four corners and in the
centre of the 25 mm (1”) Shahabad tile. Press this tile firmly over the R.C.C.
pardi in line and level. At one time, fix only a height of 1.0 meter. Total
height of the dado, above the existing ground level, is taken as 450 mm (18”).
The joints in the vertical Shahabad are then sealed
with the 1:2 cement-mortar. This is known as a pointing.
The Shahabad dado is then grouted using cement slurry
with water-proofing compound. Add approximately 1 ½ bag cement in 100 litres of
water, to prepare the cement slurry. Continue to pour cement slurry, every day,
for three to four days, until the backside of Shahabad is completely filled
with cement slurry and no more slurry is absorbed.
Cure it for at least seven days, minimum ten times a
day.
After curing, provide the final jointless
waterproofing plaster coat in C.M. 1:4 over the rough Shahabad.
The entire process mentioned above forms a box around
the structure and does not allow any water to seep through or leak from the
basement. The thickness of this treatment shall be 65 mm to 75 mm.
Underground Water Tank
A provision for pump sump is made instead of the
gutter arrangement.
Overflow pipe is located at the desired level to drain
out the excess water.
Check this pipe for its tightness before
waterproofing.
This pipe, along with the inlets and outlets, is fixed
in pardi at the time of concreting, so as to avoid the breaking of the pardi at
a later stage.
Care should be taken to waterproofing the top slab of
the water tank.
