When Are Two Coats of Paint Needed for Success?
There are varying opinions on the number of coats of paint that are needed for a successful paint job. A lot depends upon the surface, the color you are painting over, and the look you want to achieve.
If you are painting an old piece of furniture, you will find that you will need at least two coats of paint in most cases to completely cover the surface well. To make the paint adhere, wash it down with paint thinner or sand lightly all over to roughen the surface so the paint can "bite" into it and hold. Paint on one coat of primer and one coat of paint.
White and Light Colored Walls
For walls that are white or a neutral color, usually one coat of good latex paint is sufficient to give you good results. If the walls are a dark or bright color, consider a coat of primer, then a coat of paint to cover. There are new paints available that are both paint and primer in one, so you only need to do one coat.
For exterior surfaces, always sand first, then apply a coat of oil based primer to seal the wood from moisture. Then, apply either oil based paint or exterior enamel on top of this primer.