How to install crown molding
Step 1: Measure the length
Decide how much to buy: Measure the length of the walls in the room ( perimeter of the room).
Tip: Allow an extra 10 percentage wastage. If you have a repeat pattern, allow more.
Step 2: How to cut an inside and outside crown molding corner
They are referred to as outside cuts and inside cuts, and each one will be either a right or left cut depending on which side it is on when it joins. Think of each corner as if it were part of a box.
The molding that protrudes toward you would be going on the outside of the box, and the molding that recedes into a corner would be going on the inside of the box. To make this clearer here is a picture:
Step 3: Apply
Apply a pencil sized zig zag bead across the back of the molding and apply to the wall.
Press to the wall with the flat palm of your hand.
Step 4: Molding adhesives works miracles!
Once all of the molding was in place, I filled all joints with white Molding adhesives.
Walls are often not perfectly straight but fortunately you can hide all of those flaws (and also any small mistakes you make during your install) with a little bit of Molding adhesives.
Step 5: Should you paint your molding before or after you install?
If you wait until after you install to do the painting then you will have a lot of trips up and down a ladder and you will have to tape of your ceiling and wall. I have done it both ways, but in this particular installation I painted it after it was installed.