Install Door or Window Trim | Building Material Auctions | Peak Auctioneering

How To Install Door Or Window Trim

Trim defines the perimeters of doors, windows and archways. Since these mouldings are highly visible, they must integrate well with the architectural style of the room. Trim is used primarily to transition the space between the interior wall cladding, often drywall, and the door or window frame.

Tools And Materials Required

Tools
  • Nail Set or Nail Punch
  • Pencil
  • Chalk Line
  • Safety Glasses
  • Caulking Gun
  • Hammer
  • Level
  • Tap Measure
  • Mitre Saw with Finishing Blade
  • Drill
Materials
  • Finishing Nails: 1/2", 1" and 2" Mouldings
  • Silicone
Door And Window Trim

Before Assembly

This project explains how to install trim with 45 angles. The installation of trim with rosettes in the corners requires a simpler 90 cut.

Before you start, allow the mouldings to acclimatize for 24 to 48 hours in the room where they will be installed.

You can paint or stain your mouldings in advance. You’ll simply need to touch them up a bit after, and cover the nail heads you’ve concealed with wood filler. This actually simplifies the job, because you won’t need to do any masking.

Install mouldings in the same grain pattern all the way around the room.

Use a good-quality finishing blade with a minimum of 40 teeth, though 80 teeth is preferable since the more teeth a blade has, the cleaner the cut.

Pre-drill your nail holes so that mouldings do not split. Use a drill bit of a smaller size than the nails.

Steps

    36 steps
  1. Mark a reveal line 3/16" from the edge of the jamb to align the moulding. This space will be visible, uncovered by the trim. Make this line on the three sides of the frame.
  2. Check the mitre angles at the corners with two 12" test pieces cut at exactly 45.
  3. Hold the test pieces at the corner and you can see exactly how your trim is going to fit.
  4. If you see a gap, adjust the saw accordingly and cut both pieces at the new angle.
  5. Install moulding on one of the studs.
  6. Stand the moulding against the wall the length of the door frame.
  7. Mark the cutting line where the doorjamb markings meet, indicating the cutting angle.
  8. Lay the moulding flat on the mitre saw base and cut the moulding at a 45 angle.
  9. Using a level, position the moulding on the reveal line.
  10. Drill small holes in the moulding at 12" to 16" intervals and tack in 1" finishing nails to the jamb and 2" nails to the wall.
  11. Install head moulding
  12. Cut an angle that corresponds to the moulding installed on the jamb.
  13. Using a level, position the moulding on the line marked on the jamb, adjusting the angle for a precise join with the moulding previously installed.
  14. Mark the cutting line from the other corner where the marks on the doorjamb meet, indicating the cutting angle.
  15. Lay the moulding flat on the saw base and cut the moulding at a 45 angle.
  16. Lay the moulding flat on the saw base and cut the moulding at a 45 angle.
  17. Using a level, position the moulding on the reveal line.
  18. Drill small holes in the moulding at 12" to 16" intervals and tack in 1" finishing nails to the jamb and 2" nails to the wall.
  19. Install moulding on the last stud
  20. Stand the moulding against the wall parallel to the other door frame length.
  21. Mark the cutting line at the end of the head moulding, indicating the angle. Leave an extra 1/32" for fitting purposes
  22. Lay the moulding flat on the mitre saw base and cut the moulding at a 45 angle.
  23. Using a level, place the moulding on the jamb and adjust the length or angle if necessary.
  24. Using a level, position the moulding on the reveal line.
  25. Drill small holes in the moulding at 12" to 16" intervals and tack in 1" finishing nails to the jamb and 2" nails to the wall.
  26. Drive the tacked nails into the mouldings.
  27. Carefully adjust the corners and pre-drill the top of the head moulding 1" from the edge.
  28. Nail the corners with 1/2" finishing nails.
  29. Finish all nailing on the trim.
  30. Countersink the nails using a nail set.
  31. Install window trim.
  32. Mark a reveal line on the perimeter of the window frame.
  33. Start with the head moulding using the techniques outlined above.
  34. Cut the side mouldings and adjust the angles of the upper corners.
  35. Cut the angle of one side of the lower moulding and adjust.
  36. Measure and cut the angle of the other end of the lower moulding.
  37. Slide the moulding into place and adjust until the fit is perfect.