How to Install Plastic Cove Moulding

Drill holes through the preset tabs in one of the corner blocks. Hold the block square to the ceiling and screw it into place in the corner. Be careful not to overdrive the screws, as that may crack the plastic.

Add a corner block to an adjacent corner and measure the distance between the two blocks. Cut a piece of moulding 1/4 inch longer than the distance. A miter box guarantees a straight cut, but if you don't own a miter box, mark and cut the moulding carefully with a hand saw, making sure it's straight.

Run a stud finder along the wall between the two end pieces and mark the location of the studs with a piece of masking tape. Make the marks a few inches below the ceiling so that the moulding doesn't cover them.

Mark the depth of the finished moulding by holding a tape measure along the wall between the bottoms of the two corner blocks and making pencil marks every 6 inches.

Apply a bead of adhesive to the edges of the cut moulding that fit flush with the wall and ceiling. Use the type of adhesive recommended by the manufacturer of the moulding. Loading a tube of adhesive into a caulk gun makes it easier to run a steady bead.

Line up the bottom of the moulding with the depth marks and snap it into place between the two corner blocks. Immediately clean up any glue that oozes out. Screw the pieces into the studs using the masking tape marks as a guide to where the studs are.

Use a small dab of paintable caulk to fill each screw hole. Smooth it with your finger or a damp cloth and allow it to dry before painting the moulding.