Although it may be tempting to jump in and start painting, preparation is essential for best results.
If the trim has peeling paint, use a putty knife to scrape it away. Remove hardened caulking and re-caulk. Fill in holes or gaps with Spackle and allow to thoroughly dry. Hand sand to smooth the surface. Wipe down with water-detergent mixture and allow surface to dry.
If trim is unfinished, stained, or heavily patched, paint with an appropriate primer first. Allow drying. Lightly sand, wipe with damp cloth, and let dry.
Before proceeding, you may want to use a hand masker to apply painter’s tape to walls along the edge of the trim, especially if the trim will be painted a darker color than the surrounding walls. (If you are painting both walls and trim, and the trim will be a lighter or matching color, there’s no need for painter’s tape on the walls. Paint trim first, followed by surrounding walls.) Cover floor under a window or door with tarp or plastic sheeting.
How to Paint Trim Quickly
Now you’re ready to paint! Here’s how: paint the top first, followed by sides, window ledges, and any narrow parts/sides of trim:
Dip your brush into the paint, with bristles almost completely immersed. (This “fully loads” the brush, so you can quickly get more paint where it needs to go.)
Instead of wiping brush on the rim of the can, lightly and quickly slap the brush on the inside of the can a few times to reduce dripping.
Apply paint to surfaces in long, steady, one-way strokes.
When painting vertical framing, work quickly from top to bottom.
Switch to a 1-inch trim brush if painting narrow pieces of trim that may run perpendicular to the window glass.
If you are applying multiple coats, allow to fully dry, gently sand, and re-apply following the same steps.
Remove tape before paint fully dries. Start at one corner and remove in an even, steady manner.
If you are painting a window sash in which the window opens and closes vertically, keep the window open until the paint is fully dry.
If you are painting exterior trim, the outside temperature should be between 50 and 60 degrees Fahrenheit for best results.