DISTEMPERING

The main object of applying distemper to the plastered surfaces is to create a smooth surface. The distempers are available in the market under different trade names. They are cheaper than paints and varnishes and they present a neat appearance. They are available in a variety of colours.

22.6.1 Properties of distempers

1. On drying, the film of distemper shrinks. Hence, it leads to cracking and flaking, if the surface to distemper is weak.
2. The coating of distemper is usually thick and they are more brittle than other types of water paints.
3. The film developed by distemper is porous in character and it allows water vapour to pass through it. Hence, it permits new walls to dry out without damaging the distemper film.
4. They are generally light in colour and they provide a good reflective coating.
5. They are less durable than oil paints.
6. They are treated as the water paints and they are easy to apply.
7. They can be applied on brickwork, cement plastered surface, insulating board, etc.
8. They exhibit poor workability.
9. They prove to be unsatisfactory in damp locations such as kitchens and bathrooms.

22.6.2 Process of distempering

The application of distemper is carried out in the following manner:

22.6.2.1 Preparation of surface

The surface to receive the distemper is thoroughly rubbed and cleaned. The important points to be noted are:

1. The new plastered surfaces are to be kept exposed for a period of 2 months or so to dry out before the distemper is applied on them. The presence of dampness on the surface results in failure of the distemper coating.
2. The surface to receive the distemper should be free from any efflorescence patches. The patches are to be wiped out by a clean cloth.
3. The irregularities of the surface such as cracks and holes are to be filled by lime putty or gypsum and are allowed to become hard before distemper is applied on the surface.
4. If distemper is to be applied on the existing distempered surface, the old distemper should be removed by profuse watering.

22.6.2.2 Priming coat

After preparing the surface to receive the coats of distemper, a priming coat is applied and it is allowed to become dry. For readymade distempers, the priming coat should be composed of materials as recommended by the makers of distempers. For locally made distempers, the milk can be used for priming coat. One litre milk will cover about 10 m² of the surface.

22.6.2.3 Coats of distemper

The first coat of distemper is then applied on the surface. It should be of a light tint and applied with great care. The second coat of distemper is applied after the first coat has dried and become hard.

1. The distempering should be done in dry weather to achieve better results.
2. The oil-bound distemper or washable distemper adheres well to oil-painted walls, woods, corrugated iron, etc. But a priming coat of pure milk should be applied before distempering is done on such surfaces.
3. The application of distemper by a spraying pistol is superior to that by brushes. Spraying affords a smooth and durable film of distemper.