How to Install Wood Trim Around Replacement Windows

Installing wood trim adds definition to your new window replacements and transforms your home while increasing the value. Additionally, wooden trim helps frame your new windows and eliminates drafts; this is extremely important when considering the rising costs of heating and cooling. You will save money when purchasing the required materials because you are completing the project yourself and there are no additional labor costs. 

Are you a big home improvement buff? Or, just a humble homeowner who takes pride in completing a task yourself? With just a few simple steps, you can safely and easily install replacement windows with new wooden trim.

1. Measure the window frame you are working on. Make sure to measure from the top left inside edge to the top right inside edge.


2. Give yourself an a little more extra room. Approximately ¼ inches will be enough to provide a reveal of 1/8 inch on either side once the installation is complete. Note: If you would like a larger reveal, the measurements will differ.


3. Cut one end of the trim to a 45 degree angle lengthwise, you will need a miter saw to complete this task.


4. Using your ‘marking’ pen or pencil, start at the shortest edge of the angle and measure the length, then factor in the original measurement of the frame (step two) and this is where you should place your mark.


5. Modify your miter saw to ensure the next cut will be at an angle of 45 degrees and this will be your mark for the short end of the angle.


6. Verify the reveal is accurate by reviewing the angle of the cut with a level. If you are certain of the angle, use some finishing nails to hold in tact. Duplicate this same procedure for all sides. The bottom should be completed last. 


7. Review your work and if satisfied, nail the inside and outside edge(s) approximately every 8 or 12 inches.