Although painting interior walls seems pretty straightforward, certain things about it can actually be counter-intuitive. For example, did you know that it is better to roll in a W shape rather than straight up and down? The following tips will help guide you in various aspects of interior paint jobs, from paint mixing to ceiling painting techniques.
Paint Mixing involves three things: stirring, boxing, and straining & thinning
Stirring: Stir from the bottom up; this assures mixing of the thinner, clearer layer at the top with the heavier, pigment-laden material that tends to settle at the bottom. To ensure uniform color among multiple cans of paint, boxing (below) is recommended, but not usually necessary.
Boxing: If you have more than one can of the same color, and the color in one differs by even the slightest degree (and this does happen), the difference will show up on your walls. To avoid this, pour all the paint into a five-gallon mixing bucket, stir it, and then return it to the cans. You can also work from one can and whenever it gets down to about half empty, refill it with paint from one of the other cans and stir thoroughly.
Straining and Thinning: Stored paint separates, and if stored a long time, a dry paint layer forms on top. First, remove the dried paint layer with a stirring stick and throw it away. Then stir stored paint to eliminate the lumps as much as possible and pour through a cloth paint strainer. If the paint needs thinning, add water (if latex) or thinner (if alkyd) as necessary.
Painting Interior Walls
Brush Up on Brushing: Opinions vary about this, but we recommend brushing first, rolling later. And it's definitely better to take care of the ceilings before the walls. You'll want to cover the perimeter of the ceiling and the top perimeter of the walls, as well as areas that cannot be covered with the roller. While brushing, observe the following: dip the brushes to cover only about one-third. Don't rub off the excess on the rim of the can; just slap it there lightly. Holding the brush at an angle, apply the paint in long, overlapping strokes, always keeping the pressure light and keeping the entire tip of the brush on the surface, pulling away only at the very end of the stroke to avoid clumping. The handle should rest in the crook of your thumb, and your thumb and fingers should be grasping the metal band around the bristles. If it's too big to hold this way, hold it by the handle like a tennis racket. Use your angular brush on woodwork and window frames, your trim brush on corners and edges.
Strokes of Genius: Fill your paint tray with paint and run the roller over the ridges in the tray to eliminate excess paint; the roller cover should be saturated but not dripping. Then paint strokes with the roller down and up in a "W" pattern. Each W overlaps the next until the surface is entirely covered. Then the paint is smoothed with non-diagonal strokes, all in one direction (top to bottom on walls; whichever you please on ceilings). This smoothing step is especially important to blend glossy finishes, though it can probably be skipped with flat paint.
Looking Up: Ceiling Painting Techniques
• Working your way across the ceiling widthwise rather than lengthwise, begin painting a series of overlapping W's until the ceiling is mostly covered. (If it's a large ceiling, do this in smaller sections, about 6' x 6').
• Go back over the ceiling (or sections) in the opposite direction.
• As a last step to smooth out the paint, give the ceiling (or sections) a series of light, one-directional, overlapping straight strokes from one end to the other.