Here are some precautions and guidelines to finish the internal surfaces.
For starters, avoid painting your home during the monsoon or when humidity levels are high. Such conditions don't allow paint coats to dry up quickly. Moisture gets trapped between the surface and paint layers causing blistering. Ensure that surfaces to be painted are fully dry. Only for doing whitewashing and applying Snowcem, the surface need not be dry.
If painting the interior walls for the first time, apply simple white wash and leave alone for six months. This action will allow the plaster to dry fully prevent patches and spots later. It will be much better if this six-month period includes a monsoon. After six months, wash the walls fully to remove dirt, dust and flakes, preferably with sand paper so that all the lime wash is scrapped thoroughly. Otherwise, paint will not stick to the walls. Now, apply primers and paint of your choice and the results shall be excellent.
Pidilite has recently launched colour concentrates that produce high tint shades when mixed with white wash. So use these if you don’t want to see white walls in the initial months. Pidilite colors come in liquid form and are double effective than powder colours i.e. instead of 100 gm of powder only 50 gm of liquid concentrate is required. Take care that no ‘neel’ is added to the lime solution if using a colour concentrate. For more, read on:
White washing
Always choose fresh, unslaked, non-hydraulic lime. See that it is of class C category or Dehradun or Narnaul quality. To prepare solution, add water to lime and not lime to water. Add 5 litre water per kg of lime. The final solution should look like thin cream not water. Leave the mixture for at least 24 hours, preferably 48. Use 150 gm lime per sq metre of surface if one coat is to be done. For two coats, let it be 250 gm per sq metre. In a newly constructed house, at least three coats are recommended. However, as you are using whitewash temporarily, two coats are sufficient. Add an adhesive like DDL or SDL to the mixture at a rate of 4 kg per cu m of solution. Fevicol or gum can be the second option if DDL is not available. This will prevent whitewash from sticking to your clothes and body.
The solution: Add some ‘neel’, say 30 gm per 10 kg to the lime solution. It accentuates the whiteness and brings brightness. But the quantity of ‘neel’ must be restricted otherwise walls may give indigo reflection. For application of whitewash, use ‘moonj’ brushes. As a precautionary measure, tie gunny bags to the feet of ladders as their repeated pulling or shifting may leave marks on the floor. See that in each coat the brush passes every point four times — left to right and reverse; up to down and reverse.
Take your pick
For painting internal walls, choice is between distempers and emulsions. If you choose emulsions, there are extra premium acrylic, premium acrylic and acrylic ones to pick from. All acrylic emulsions are durable and give smooth finish to walls. You can choose glossy, semi-glossy or matt finish. Oil bound distempers too are durable, if applied the right way and economical in comparison to emulsions.
Dry distempering: If you are choosing dry distemper for internal walls, see that it is IS 427 marked. Dry distemper comes in powder form and has no resistance to water. It can’t be washed. About 1.5 litre water is added to 2.5 kg distemper. Use lukewarm water instead of cold, allow the solution to stand for at least 30 minutes, stir well and use. It will cost not more than Rs 1.25 per sqft. However, it has a short life. It has been seen that sometimes people do first coat of whitewash and then apply distemper. Don’t. Use a white chalk solution in water as primer to distemper. Dry distemper should give a coverage of about 6 sqm per kg of distemper for two coats. Mix DDL or Fevicol to dry distemper for better adhesion. Golden Champion and Goldy are good brands.
Oil bound distempering: Oil bound distemper (OBD) is washable, doesn’t come off on washing and scores over dry distemper. If you are choosing distemper, prefer OBD. It contains an emulsion of drying oil or varnish that resists water. See that it conforms to IS 428. Use thinned distemper itself as primer to OBD. Four parts of OBD are mixed with one of water to prepare its solution for application. Know that OBD shouldn’t be applied on new plaster for six months at least otherwise all its oils will be soaked by the plaster. However, if you can’t afford to wait, here is a solution. Get some ready mixed alkali resistant paint as per IS 109 and apply a coat of it. Now, you can do OBD after two days only. OBD shouldn’t come off 24 hours after its application. It will cost you around Rs 2 per sqft and give a coverage output of about 6 sqm per litre of paint for two coats. You need not mix DDL to OBD or plastic emulsion as these have a good grip.
Emulsions: If using plastic or acrylic emulsions on internal walls, add water in the first coat only. For quantity of water to be added, follow manufacturer’s guidelines. Choose plastic emulsion of a reputed brand such as Asian, Berger, ICI or Nerolac. IS 5411 mark for these paints stands withdrawn, so don’t look for it. Use manufacturer’s putty to repair the wall if required before application of plastic emulsion. Further, rub the wall with 180 number sand paper on drying up of putty and apply a coat of primer over it. On drying up of primer coat, sand paper with 320 number. Now, apply the final paint and you will receive excellent results. Tell the painter to clean all plastic emulsion drops from the floor immediately as it may become difficult to remove them later. The first coat will dry up in four-five hours. Plastic emulsion paint should give around 8 sqm coverage per litre of paint for two coats.
