1. Polythene sheets / gunny bags to be laid on the
ground to prevent wastage.
2. Do not start ANY Gypsum Work if the surface has not
been properly hacked at the rate of 1 hack per sq inch (minimum) duly
checked by the Engineer-in-charge.
3. The wall is first marked vertically at 600 mm
centres then checked with straight edge or line (preferably aluminium square
tube) to find the high spots which are used as guide for level to be set. If
the high spots are too high, this fact must be brought to the notice of the
engineer in charge who will order chipping of the high spot or he will have the
surface rendered/plastered so that the level may become true. This plastered
surface must be cured for at least 10 days before gypsum is applied.
4. The background should be suitably wetted with a
brush 5-10 minutes before plastering to displace the trapped air & for a
good plaster contact with the surface.
5. Four points (by putting plaster with flat surface)
are fixed in level & plumb at each corner of the wall to determine the
thickness of the plaster required to be done.
6. 40mm wide strips of plaster are fixed. Then the
points are applied vertically, in level & plumb of both ends of the wall.
7. These vertical strips are then made with plaster at
even 600 mm centres on the entire area of the wall to ensure level and plumb of
the strips to be in line.
8. Apply plaster to the surface of the wall with
trowel to the required thickness & finish the surface setting straight edge
(sq tube) horizontally by then placing on the vertical strips already fixed
above with firm pressure.
9. The best results are obtained by applying a thick
coat then turning back with the same batch of material to fill out to the
required thickness.
10. A featheredge is used to straighten the plaster to
a reasonable plane, whilst at the same time filling in any slacks or hollows
when the plaster has stiffened sufficiently. Further ruling of the featheredge
is necessary to achieve a flat surface.
11. As the plaster stiffens progressively, further
flattening & paring should be carried out with spatula.
12. When the plaster is sufficiently formed the surface
should be scoured lightly with a sponge float & light application of water,
if necessary to raise the flat & bring the surface to a suitable condition
of finishing.
13. Closing in with the trowel should commence as soon
as plaster starts to set, followed by a final trowel at the appropriate time.
14. Do not over polish.
15. Decoration should be delayed until the plaster work
has dried out thoroughly.
16. a) Ensure that straight ede remains straight and
does not bend with the passage of time or rough use.
b) Change the straight edge, if required.
