Q: What is the correct way to paint the mitered corners of window casing to avoid brush marks?

A: Scott Burt, owner of TopCoat Finishes in Jericho, Vt., and a presenter at JLC Live, responds: Generally speaking, when painting window or door casings (mitered or butt jointed), it is best to work from the top of the window down and to always brush with the grain or in the direction of the wood.

Painting corners of trim is a game of avoiding the look of the brush marks crossing over the joint. In either case (miter or butt), you can begin by brushing through the joint in one direction or the other. Then go back and “point and pull” brush strokes from where you crossed through. With butt joints, it’s easy to go back and brush straight out from the joint line.

A mitered joint where the wood ends in a point is a little trickier. Here, you point, or lightly press, the wet brush bristles onto the surface so that they extend into the point of the miter (see photos, below).

Scott Burt
Scott Burt

Then you pull the brush back horizontally for the head casing and vertically for the side casing. As with any fine finish skill, the technique of pointing and pulling takes a bit of practice to master.

One thing to keep in mind when painting trim is that all the brush strokes have to happen while the paint is good and wet—as in, immediately. If the paint starts to dry before your final brushing, the areas where you’ve crossed over the joint will flash (change luster and stand out from the rest of the finish). This is a particular risk with the new generation of latex and waterborne trim paints—they tack up quickly. You can use a product, such as Floetrol, that keeps trim paint wet longer for brushing out.

All of this points to having a good eye, the right brush (size and style), and the ability to lay the paint out properly and leave it. Overbrushing is one of the most common mistakes people make when painting trim.

Photos by Scott Burt