Paints and varnishes are used to protect metal, timber or plastered surfaces from the corrosive effect of heat, moisture, gases and changing weather conditions. Paints are also used to improve the appearance of a structure.
Paints are classified as per their basic ingredient as follows: –
- Oil Paint.
- Enamel Paint.
- Fireproof Paint.
- Cellulose Paint.
- Aluminium Paint.
- Cement Paint.
- Textured Paint.
The serviceability expected from a surface after painting and the purpose of painting shall be decided beforehand. According to the decided purpose, a specific paint, delivering required results, should be selected. The purpose for painting any surface is to make that surface impermeable, heat resistive, durable & elegant. Simultaneously the durability, maintainability of the paint in application & the cost of the paint also governs the selection process.
Considering all these properties of the paint as well as the desired purpose of painting; a proper painting material shall be selected.
The best quality of painting lies in the preparation of the surface. Therefore, utmost care shall be taken in ‘Preparing’ a surface.
PREPARATION OF SURFACE FOR INTERNAL PAINTING:
- The surfaces should be completely dry
- The surface should have no patch of efflorescence.
- Surface should be cleaned with wire brush., for dust, loose scales etc.
- The surface should not be rough. If the surface is rough, sand paper shall be used to smoothen the surface.
- Cement plastered surface must be washed and allowed to dry.
- All gaps, cracks and undulations in plaster works shall be filled and smoothened.
- All activities involving cement shall be completed prior to painting.
- All parallel & subsequent works creating probable damages to the painted surface,shall be planned and controlled so as to avoid the damage (for e.g. final floor polishing).
- After preparation of surface, apply thick coat of primer to walls and ceilings.
- Apply filler (putty) on all the walls and ceiling in horizontal and vertical direction to cover all undulations and minor cracks, on the next day
- After 24 hours, gently rub the surface with fine sand paper for proper bonding of the paint.
- Clean the surface with cotton cloth.
- Mask all the doorframes, window frames and all fixtures.
- Apply first coat of paint in vertical and horizontal direction simultaneously.
- On the next day, check for undulations if any, and rectify the same with putty.
- Confirm the completion of the parallel activity (switches, plates) before the start of the subsequent coat of paint. An interval of minimum 24 hours shall be maintained between any two coats of paint. .
- Clean all the doors, windows and fixtures and floor with proper care.
- Mask all the fixtures and adjoining walls of the surface to be polished.
- Scrap the surface to be polished by sand paper. No. 80 shall be used.
- Apply a sealer coat by spray machine.
- Fill the depressions, if any, with wax.
- Scrap the surface with sand paper, gently to obtain smooth finish.
- Apply the first coat of polish.
- Scrap the surface as required.
- Apply the final coat of polish uniformly.
- Clean the surface with clean cotton cloth, gently.
External painting shall be started only when, all the plaster, waterproofing, plumbing lines, electrical works, rectifications and repair work are completed.
- Prepare firm scaffolding for painting to walls.
- Clean the surface to make free from dust, loose mortar and extra deposition if any.
- Fill all the cracks with waterproof crack-fill compounds.
- Mask the external surface of window and railing etc.
- Water the surface to be painted atleast 12 hours before painting.
- Mix the paint thoroughly, as per the manufacturers instruction.
- Apply first thick coat of paint, uniformly in vertical and horizontal directions simultaneously.
- Cure the cement paint atleast for two days.
- Second coat of paint should be applied only after curing of first coat is completed.
- Application of paint is to be done only after checking the paint life and manufacturers’ instructions.
All painters must wear safety belts and helmets while working on and around scaffolding area.