How to Install Stair Trim Molding

  • 4-12 hours
  • Beginner
  • 75-150
What You'll Need
Pencil and ruler
Trim and scrap trim
Electric saw
Wood glue
Sand paper

Installing a stair trim can add a touch of elegance to any space. It will not cost you as much as a drastic wall makeover but it certainly will tie together and improve the overall look of any home. Most of all, any homeowner can undertake the project.

Step 1 – Set the Template

With the use of a pencil, draw a line that is three inches parallel to the top landing of your stair case. Take a piece of scrap trim that must be at least one foot in length. Now go to the bottom landing of your staircase and look for the intersection between the stringer and the landing. Once you’ve found that, measure 3 inches away from that intersection and make parallel line. From that mark, make a straight line all the way down.

Place the trim on top of the stringer and slide the trim up from the bottom landing to the top, marking as you go. Stop when the sloping line has intersected with both parallel lines from both landings. You have now created a diagonal line that is parallel as well with the stronger of your stairs.

Step 2 – Mark the Angles in the Trim Molding

To find out what angle the cut in your trim molding should be, simply get a scrap trim and place it in the sloping stringer. Now slide it up until the top edge of the molding touches the intersecting line that you just marked. Now look at the bottom edge of the molding. Locate the intersection between the stringer and the landing and then mark your trim molding. All that you have to do is to connect the top corner with the mark that you just created in bottom edge using a straight ruler.

Use an electric saw to carefully cut the line that you just made. You can now use that scrap as a template for the actual trim molding that you plan to install.

Step 3 – Install the Trim Molding to the Stairs

Try to fit all the trim moldings together to see if everything fits snugly. Make necessary modifications if needed. If you’re satisfied with the angles, nail into place the trim molding on the top of the landing. Make sure that you follow the lines you made precisely. When you’re done nailing the first trim molding into place, apply a thin layer of wood glue on the edge of that trim molding where you’ll be creating a joint. Now place the second trim molding by sealing the joint. Secure that trim molding also by nailing it to the wall. Wipe off any excess glue that has squeezed out from the joint. Sand the joint once the glue has dried.

Step 4 – Apply Finishing Touches

You may then paint the trim molding so that the new addition ties in with the rest of the room.