How to Paint Trim


Thinking of ways to brighten up a space without breaking the bank? Painting the trim around windows, doorways and baseboards is a quick way to brighten up the appearance of any room in your home. Painted trim not only completes the design scheme of any room, it also protects mouldings and transitions from everyday wear and tear.

Never painted trim before? Don’t worry! It’s easy to paint the trim in your home as well as any professional painter. It may require a little time and patience at first, but the end result is very satisfying, and well worth the effort!

The process of painting trim is broken down into two parts: preparing the surface, and applying the paint.

Get your painting project started!

First, you will need to go to your local GNH Lumber and grab some supplies:

Supplies Needed

  • Painter’s tape
  • Interior primer such as Benjamin Moore Premium Fresh Start® Premium Interior Primers
  • Interior latex paint (semi-gloss or high-gloss finish)
  • A damp sponge
  • Tack cloth
  • Three types of Sandpaper (120-grit, 100-grit and 80-grit)
  • Spackle
  • Spackling or putty knife
  • Paint trays
  • Paint sticks
  • Paint brushes (2-inch angled brushes)

Part 1 – Preparing the Surface of the Trim

  • Step 1: Wash.

    Using a damp sponge, clean the trim of any dirt, grime and grease. You may be surprised by the dirt buildup on your trim, especially floor trim. Use the rough side of a sponge if needed for tougher to clean areas. This will ensure a clean starting surface.

  • Step 2: Sand.

    Allow each piece to dry, then sand all sides of the trim that you are going to paint until the surface is smooth to the touch. If your trim is new or already smooth, lightly sand using 120-grit sandpaper until all shine disappears. If the trim is rough and worn, start by sanding with coarse, 80-grit sandpaper. Wipe away any dust and sand with finer sandpaper (100- or 120-grit) until the surface is smooth. Tip: Use a damp sponge to wipe away any excess dust left over from sanding.


  • Step 3: Spackle.

    Fill in holes, dents and cracks with a lightweight spackling compound (follow directions on the spackling container for best results). When the spackle dries completely, lightly sand the spackled areas using 120-grit sandpaper to smooth out the surface. Use tack cloth to remove any sanding dust from the trim.

  • Step 4: Mask.

    Dust off walls and ceiling around the trim to ensure the painter’s tape adheres properly. Apply painter’s tape to protect the walls and ceilings surrounding the trim, being careful not to stick the tape to the trim itself. Tip: Use one long piece of tape instead of multiple shorter pieces to prevent paint from bleeding through. Here’s how! Pull out 3-to-4 inches of painter’s tape and firmly press it to the wall or ceiling. Hold this “starting spot” in place, pull out 6 more inches of tape, and firmly secure it, smoothing out any air bubbles or wrinkles in the tape. Repeat this process until you’ve masked the areas you don’t want to paint. Once the tape is in place, use a clean spackling or putty knife to firmly press down any tape edges to ensure proper adhesion and prevent the paint from bleeding through where the tape meets the trim.

Part 2 – Apply the Paint

  • Step 1: Primer.

    Open your primer, mix it thoroughly with a paint stick and pour a small amount into a paint tray. Dip an angled brush into the primer, covering no more than ½ inch to 1 inch of the tip of the brush. Tip: use the side of the tray to wipe excess primer off the brush to avoid drips while priming. Apply the primer to your trim, making sure to cover both bare wood and spackled areas. Allow primer to dry for 24 hours. After drying, if any bare wood or spackle remains, apply another coat of primer to the trim.

  • Step 2: Sand.

    Once all the primer coats are dry, lightly sand the trim using 120-grit sandpaper to eliminate brush strokes or paint drips. Use a damp sponge or tack cloth to remove all sanding dust.

  • Step 3: Short Strokes.

    Thoroughly mix your top-coat paint with a paint stick and then pour a small amount into a clean paint tray. Dip the angled brush into the paint, covering no more than ½ inch to 1 inch of the brush. Use the side of the tray to wipe excess paint off the brush to avoid drips while painting. Apply paint to the trim using short brush strokes running the length of the trim. Repeat the motion until a few feet of trim (not the full length) are covered in paint.

  • Step 4: Long Stroke.

    Smooth over the series of short brush strokes with one long brush stroke. Do not add more paint to the brush. Instead, drag the brush in one long motion over the freshly painted trim. Repeat if necessary, depending on the width of the trim.  This helps to create the appearance of long, smooth strokes.

    Tip: Keep in mind that wider trim may require three or four long, parallel brush strokes. Thinner trim may only require one or two long, parallel strokes.


  • Step 5: Repeat.

    Now you can begin painting the next section of trim following steps three and four. Repeat until the trim is fully painted.

  • Step 6: Remove Tape.

    Before the paint dries completely, carefully pull away the applied painter’s tape, and then discard.

Following these steps and tips produce beautifully painted trim with professional quality finish. Remember to take your time, and, when choosing the right paint or primer, your local GNH professionals are here to help.  Good luck!

Do you have a painting project in mind?

Stop in to your local GNH Lumber to learn more and to get that project started today. Get your painting project started!

Paints & Stains at GNH Lumber