Drop ceilings are relatively easy to install and allow access to the rafters above. That's useful in a basement remodelling job, where you may want access to wiring or plumbing above the ceiling. Lighting in a drop ceiling is often supplied by fluorescent light fixtures mounted to the rafters. To allow the light to illuminate the area below, plastic light diffusers are installed in the place of ceiling panels.
Purchase a light diffuser panel at a home improvement store. You'll usually have a choice of a few different styles. Choose the one that best matches your ceiling's style and decor.
Measure the opening in the drop ceiling where the diffuser will be installed. Diffuser panels come in standard 2-by-4-foot sized panels. In most cases your opening will be the same size as the panel. If it isn't, go to Step 3. If it is, proceed to Step 4.
Place the panel onto a hard surface and measure out the correct dimensions onto the panel. Place a straight edge onto the panel and score the panel several times with a utility knife, until the excess plastic can be easily snapped off.
Angle the panel and bend it slightly to push it up and into the opening in the drop ceiling. When you've positioned the panel, release it so it settles into the opening and rests on the cross pieces of the drop ceiling grid.
If the panel doesn't settle all the way into the grid, reach over to it from an adjacent panel and push down gently.