How to Install Miterless Crown Molding

The difficulty in installing crown molding in some homes is that after time the home has settled and the walls and ceiling are no longer perfectly square. This makes using the typical mitered crown molding nearly impossible. You can avoid these problems entirely by using miterless crown molding. It uses corner blocks so the molding on either side can be cut straight, rather than at an angle, giving your home a clean, finished look without the headaches.

  1. Begin by using the double sided tape to attach the corner block into the corner. If the walls are not square, use a file to shape your corner block to fit. Make sure to not damage the areas that will be showing. Install all the corner blocks.

  2. Measure your first piece of crown molding. If it is too long, cut it down. Make sure it will fit snuggly between the corner blocks. If the wall is longer than a single section of crown molding you have, you can use a relay block. These are similar to corner blocks but they go in the center of a straight wall. For the walls you are going to use a relay block. Cut your molding into equal lengths so that the relay block is centered in the wall.

  3. With the first section of ceiling molding, flush up to the side of the corner block and secure it into place with finishing nails. Drive the nails into the wall studs. If you are using a relay block, install it now with the double sided tape. Test fit the next piece to make sure the crown molding fits between the blocks. Install the next piece of molding. Continue with this process all the way around the room, making sure the molding fits as closely together as possible.

  4. Using high quality caulk that can be painted, caulk between all the molding pieces and the ceiling. Fill in any small gaps between molding pieces. Use a nail set to sink the nails slightly and caulk over the holes. Once dry, you can paint the molding.


  • Use a dust mask and eye protection for this project.
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