Wood exterior window trim requires a significant amount of maintenance. Sun, wind, rain and snow all contribute to wear and tear and peeling paint. Luckily, when window trim is prepped correctly, a new coat of paint can withstand against weather and natural wear for many years.

Step 1

Assess the Condition

Peeling paint is one of the most obvious reasons your window trim requires maintenance. Paint that flakes away leaves your wooden windows more susceptible to weather damage and rot.

The glazing around the window panes may need to be replaced too. It’s not uncommon for old glazing to loosen and chip away similar to old paint, especially on the tops and bottoms of each pane where rain water may run down and soak behind old glazing. Lack of glazing will result in loose glass panes and contribute to drafty and inefficient windows.

Check all of the hinges and the windowsill. If they are they dirty or contain a collection of spider webs then the windows will need to be cleaned before you paint the window trim.

Be wary about lead paint layers in older homes. If you have suspicions that lead paint was used on your home pre-1978, buy an inexpensive testing kit at a hardware store. If it tests positive, follow all safety precautions to avoid inhaling it, letting the dust get in your eyes, on your skin, or letting paint flakes gather in your soil.


Lead exposure is a serious health risk for kids and pets that can lead to irreversible damage. Get the CDC's tips for safely dealing with lead.

Step 2

Scrape Loose Paint, Caulk and Glazing

Use a putty knife or multi-use paint scraper to remove flaking paint from the wood trim and loose glazing from the panes. Also remove cracked or peeling caulk (it will often peel free from its surface).

Step 3

Sand Painted Surfaces

Use sandpaper to smooth the transitions between old paint and raw wood, and to prep the existing paint finish. A well-sanded surface improves the chance of adhesion for the new primer and paint.

Step 4

Dust and Clean Windows

Use a dry cloth to dust the trim, panes and windowsill and then use a diluted soap concentrate and a small rag to clean the windows and windowsill. Use an old toothbrush dipped in the soap to gently scrub around all hinges and along the edges of the glass panes in tight crevices.

Step 5

Caulk Exposed Crevices

Run a bead of outdoor caulk anywhere that you removed it during initial clean-up, and pay special attention to the condition of the caulk along the inside edge of the windowsill. It’s important to keep that ledge sealed to prevent rain water from seeping in and rotting the window frame.

Step 6

Repair Window Glazing

If window glazing repair is necessary, allow the wood between glass panes to dry overnight. Though the product sometimes comes in a caulk-like tube, I find it easier to work with a putty knife to insert the glazing. Mix the glazing using the knife and then use the knife to apply small amounts to the edge of the pane at an angle. Compressing the glaze against the trim and glass minimizes the chance of water seeping behind the glazing and rotting the trim wood, also applying the glaze at an angle will allow water to run-off. Work slowly to achieve a smooth finish. The glaze will need to cure for 7-14 days on average, which means you will have to wait a few more weekends to prime and paint your windows. But it also means that the putty doesn’t dry immediately, making it perfect for the first-time window glazer.