How to Repair Damaged Trim and Molding Before Painting

Why It Matters

Edmonton homeowners often overlook damaged trim, thinking a new coat of paint will hide imperfections. In reality, paint highlights flaws, especially if the surface is uneven or cracked. Proper repair ensures a professional, long-lasting finish and adds real value to your home.

Tools & Materials You’ll Need

• Utility knife

• Wood filler or spackling compound

• Sanding block or fine-grit sandpaper (120–220 grit)

• Caulking gun and paintable caulk

• Putty knife

• Painter’s tape

• Primer

• Mild detergent and clean cloth

• Replacement trim (for severe damage)

• Nail set (if nails are exposed)

Step-by-Step Guide to Repairing Trim and Molding

1. Inspect All Trim Thoroughly

Walk through your space and inspect:

• Baseboards

• Door and window casings

• Crown molding

• Chair rails

Look for dents, chips, old caulking, loose nails, or water damage—especially near floors or windows.

Tip: If you’re painting over oil-based paint, it may need sanding or priming for adhesion.

2. Clean the Surface

Use a mild detergent or de-greaser to remove dust, oil, or grime. Edmonton homes can accumulate unseen debris over the winter months—cleaning is key to proper adhesion.

3. Remove Old Caulking and Loose Paint

Use a utility knife or putty knife to scrape away:

• Loose or peeling paint

• Old, cracked caulking

• Flaking wood filler

This creates a clean, paint-ready surface and helps the new materials bond properly.

4. Fill Dents, Holes, and Cracks

Use a high-quality wood filler for deeper imperfections and spackling compound for minor surface dings.

How to apply:

• Press filler into gaps with a putty knife.

• Slightly overfill; it will shrink as it dries.

• Allow to dry fully, as per manufacturer instructions.

5. Sand for a Smooth Finish

Once the filler is dry, sand it flush with the surrounding trim using 120–220 grit sandpaper. This step ensures your new paint lays flat and smooth.

Pro Tip: Wrap your sandpaper around a small block of wood for straight, even sanding on flat trim.

6. Re-Caulk Where Needed

Use paintable caulk to reseal the gaps between your trim and the wall.

Where to caulk:

• Along the top of baseboards

• Inside corners of molding

• Gaps between trim joints

Smooth the caulk with a damp finger or caulking tool for a clean finish. Let it dry before painting.

7. Prime the Repaired Areas

Apply a quality primer to:

• Wood filler patches

• Sanded spots

• Areas prone to moisture

This seals the surface and prevents flashing (visible dull spots) in your final coat.

8. Optional: Replace Severely Damaged Sections

If your trim is cracked, swollen, or warped beyond repair, consider replacing that section. Most Edmonton hardware stores carry matching molding profiles. Cut carefully, secure with finish nails, and repeat the prep steps above.

9. Tape Off Walls and Flooring

Use painter’s tape to protect adjacent walls and flooring from drips and brush marks.

10. Paint Your Trim

Now that your trim and molding are repaired and prepped, you’re ready to paint!

• Use a high-quality semi-gloss or satin paint for durability and easy cleaning.

• Apply two light coats rather than one heavy coat.

• Use an angled brush for precision.

Local Considerations for Edmonton Homeowners

• Dry Winters: Indoor heating can cause wood trim to shrink and crack. Repair before painting to prevent visible flaws.

• Moisture in Basements: Make sure trim is dry and mold-free before sealing or painting.

• Seasonal Expansion: Alberta’s temperature swings can cause joints to open or flex—caulking and priming are essential to reduce visible damage later.