When you are painting walls and ceilings, bear in mind the preparation of surfaces for paint is the most important part of the process.

Without a smooth, clean and dry surface, no amount of care in applying the paint is going to give a professional finish.

New plaster

Make sure that new plaster is absolutely dry before applying paint to it, as water trapped in the plaster will weaken the adhesion of the paint and can cause blistering. Some plasters have an alkaline nature and when the plaster dries out, white, fluffy alkaline crystals may be deposited on the surface. Remove these deposits with a dry brush before painting. The plaster should, in any case, be dry-brushed before painting to remove any surface dirt, and scraped to remove and plaster splashes. Make good any cracks or holes with a plaster-based or cellulose filler. After preparation, the plaster must be sealed with the correct sealer – ask your paint supplier which is the best option for your particular application.

Wallpapered surfaces

It is advisable to remove existing wallpaper before painting, as it is never possible to know how well the paper is adhering to the surface and the finished work can be spoiled later by unsightly blisters or lifting edges. Also, it is not normally possible to wash wallpapers properly, and as a result, nicotine and other deposits on the paper may be left, which will end up staining the paint coating. This is especially true of emulsion paints, which are particularly good for dissolving nicotine. Stripping the wallpaper can be quite a difficult and time-consuming job. If you have a large area, hiring a steam stripper will save you a lot of time and money.

Old plastered walls

After stripping the old wallpaper, it is important to remove any trace of paste and size left on the surface, as these can cause newly applied paint to flake. Remove old paste by washing the wall with warm water, and when the surface is dry, sanding it with glasspaper. Afterwards, fill the surface in the same way as you would do for new plaster. If the surface is a mixture of bare plaster and painted areas, before you paint it, it is advisable to first plaster the wall with a thin layer of Rhinolite for a super smooth end result.

Existing painted surfaces

Painted surfaces must be washed down to remove dirt and grease. In bedrooms and halls, a mixture of washing powder and warm water should be sufficient to remove it. But in kitchens, where the grease is thick, stronger cleaning agents, such as a washing soda solution for example, may be required. Whatever cleaning solution you choose, be sure to properly rinse the walls with water after they have been cleaned, as residues of the cleaning solution may attack and soften the paint. Failure to remove grease can prevent the paint from drying. Shiny gloss surfaces should be lightly abraded, and then rinsed, to provide a good key for the new paint. This is particularly important when the gloss is to be covered with an emulsion or silk finish. - Antonella Des

Pictures courtesy of:
Southern Painting: www.southernpaint.co.za.

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