Base Coats and Primers in a Paint Job: Why Are They Important?

A lot of homeowners overlook the importance of base-coating their walls. In fact, base-coating your wall has more functions than you’d imagined. The base coat seeps into the pores on the wall, attaches itself to the wall surface and adheres the topcoat tightly to the wall. In other words, it is the bridging element between the topcoat and the wall surface. Also, the base coat seals the wall surface and prevent the alkaline salt in the cement to permeate through. It lowers the amount of topcoat paint you will have to use. To actualise the functions of base coating, the paint has to be oil-based, and applied evenly, skillfully. The topcoat is what you see, so its application requires highly-skillful, professional hands. Determine whether the base coat is completely dry before applying the topcoat. The topcoat has to be done on one go, so that the resulting colour of the wall is uniform and even throughout. Do not add water into the topcoat paint, especially not for dark-coloured paint. If the amount of water you add for each can of paint varies, the resulting wall will have a range of colour variations too! Yikes.

Different applications for different types of paint

White paint

Choose white paint with high adhesive power. Paint it over instead of spraying it on, so as to avoid wasting paint. Do not dilute the paint too much. After three to four coatings, buff the surface with water to smoothen the coating.

Topcoat

Before painting, apply a few layers of spackling. The first layer of spackling has to be thick so that the adhesion is strong and the coating substantial. For the second layer, lower the amount of adhesive in the paint. And for the third, it depends on the professional workers’ judgement. For cement walls, add white latex to the first layer’s coating. This is not necessary for the second and third layer. For ordinary refurbishing of old buildings or flats on the lower floors, use an alkali-resisting primer to base-coat the walls. This is because walls of the old building are prone to discolouration, while the high humidity of lower floors leads to mould growth. Design: Black N White Haus HKDecoman, now going global as Deco-Man, is a Hong Kong-based renovation platform which provides professional consultancy services and pioneers in the development of A.I. homeowner-engineer matching. We aim at educating the public about the art of home renovation and have our eyes on transforming the traditional renovation industry, bringing standardisation, transparency, convenience and automation to the business.