While in case of wood, sealing & protection are two most important aspects, in concrete and drywall, for instance, one simply wants to seal the surface and create a solid bond. If applied correctly, one need not worry about drying and moisture. Concrete loves water in the initial stages of construction. On the contrary water has to evaporate form the water-base paint. If the water penetrates the concretes, then the paint may appear pock-marked & start to peel off. Also there won’t be smooth finish. Many coats of expensive paint will be required.
Metals used in construction are prone to rust & corrosion due the elements. Mere paints are not enough for their protection. Herein, a paint primer can protect the surface itself and keep moisture locked out. These are of course special purpose primers. Some precautions that need to be taken are polishing the metal surface so that primer & later paint may stick evenly.
Plastic surfaces though rare in home construction, can benefit from a coat of paint primer. If the paints are porous in nature primers help in filling those pores & give a smooth finish. Primers also help when you are putting a light shade over a darker one. Like starting afresh.
Primers are also needed to join two different paint types together. Example: When latex paint is applied over oil paint.
Without a primer in place, repeated thunderstorms will their toll & will form a thriving base for mold, mildew and warping.
It’s a misconception that outdoor paints are naturally waterproof. However, their assumption spurs from their ability to repel rainwater. A proper coat of primer enhances the ability of paint to withstand the forces of nature that would have otherwise destroyed not only the looks but also threatened the structural integrity if neglected.
Under no circumstances, should be used for hiding blemishes or “sealing in” mold and mildew. If the substrate has already absorbed or produced an organic population such as this, it is absolute must to clean off any residue before applying primer & paint. One has to let the surface dry for several hours & see if the problem recurs. It is always a good choice to throw away a rotted plank & scrap of bad concrete than apply primer to simply delay the inevitable.
Earl's Paintwork is the best Calgary Interior Painting.
