What are the specifications for preparation of tiles for POP tiles ceiling?

The specifications for preparation of tiles for POP tiles ceiling are following:

• Tiles of POP reinforced with hessain cloth are prepared in suitable sizes.
• The maximum size of the tiles is limited to 75 cm in each direction.
The longitudinal and header scants are so arranged that the tiles can be fixed to form panel arrangement.
The edges of the tiles shall be provided a neatly formed symmetry of around 5 mm width and of 8 mm depth unless the tiles are provided with a cover fillets over joints.
The glass sheet, surface on which form is kept and the form sides shall be given a thin coat of non-staining oil to facilitate the easy removal of the tiles.
Plaster of Paris should be evenly spread into the form up to half the depth.
The weight of hessain cloth should not be less than 230 gms per meter and it is pressed over the plaster of Paris layer.
The ends of the hessain cloth are turned over at all edges to form a double layer to a width of 5 cm.
The hessain cloth is of an open webbed texture so as to allow the plaster below and above to intermix with each other and form an integral the whole.
• The form is then be filled with plaster of Paris which is uniformly pressed followed by wire cut to an even and smooth surface.
• Such molded tile is allowed to set initially for an hour or so and then removed from the form and allowed to dry and harden for a week.
• After drying and hardening a good tile gives a ringing sound when struck.
• The tiles are true to shapes and sizes with clean and regular symmetries.
• The exposed face is truly smooth and plane.