Cutting Outside Miters


The biggest part of putting up moulding is not holding it in place and driving a nail every 16 inches. It's the few inches around the corners, that will require your greatest attention.


Miters are most easily cut on a power miter saw. The saw can be set to cut at any angle - set it to 45 degrees for a standard 90 degree corner. The saw can be set to 45 degrees to the left or 45 degrees to the right. So it's a little confusing at first, but once you get the hang of it, it's automatic.

Most people like to install moulding working from the left side of a wall to the right, and these directions assume that you will, too. It's hard to get a miter exactly where you want it to be on a board. When you're mitering, cut the miter on a piece a little bit longer than you'll need. Cut it to length by making a square cut. Before making any cuts use a level and lightly mark a guideline for the moulding along the wall.




Step 1: Miter the first piece of moulding

Step 1: Miter the first piece of moulding Start with two pieces of moulding, each a few inches longer than the section of wall they will cover. Set the saw blade 45 degrees to the right. Put the moulding that goes on the left-hand side of the corner against the fence to the left of the blade. Cut the moulding, leaving it long.

Step 2: Miter the second piece

Step 2: Miter the second piece Turn the saw blade 45 degrees left. Put the second moulding to the right of the blade, and cut a miter in it that leaves the board longer than finished length.

Step 3: Lay out the length

Step 3: Lay out the length The point of an outside miter sticks out beyond the corner by the thickness of a moulding. To get the right length moulding, measure the wall, add the thickness of the moulding, and make a mark that distance from the mitered point of the moulding. It's sometimes easier if you do it in steps, as was done in the photo. The moulding shown here runs along a short wall of an alcove, which measures 10 3/8 inches. The moulding is 1/2 inch thick. If you look closely, there's a light mark on the moulding at 10 3/8 inches; the second mark, which shows where to make the cut, was made by  adding to that the thickness of the moulding.

Step 4: Cut the moulding to length

Step 4: Cut the moulding to length Set the blade for a square cut (0 degrees), and lay the moulding on its back on the saw table. Cut the moulding at the line.

Step 5: Install the mitered piece

Step 5: Install the mitered piece Test fit the pieces against the wall to check alignment. Nail one of the mouldings on the wall, dab wood glue into the mitered surface on the second piece, and nail it in place, too. Reinforce the joint by driving 1-inch brads through the faces of both mouldings, through the miter joint, and into the other moulding.

Things to consider:

• If cutting crown moulding it’s a best practice to cut it upside down. Meaning the wall edge should be against 
  the fence with the top edge on the saw bed.

• You can distinguish outside and inside corners from one another by following this simple guideline. On outside 
  corners the cut edge is hidden by the face of the moulding when looking head on. Inside corners show both 
  the cut edge and finished face when looking head on.

• Wall corners are rarely a perfect 90 degrees. Always use a framing square or protractor/angle finder to 
  find the true angle and adjust the miter cut accordingly.