Project Guide

How to Install a Peephole in a Door

  • Use a tape measure to locate the center of your door and mark the spot where you want to install the viewer. Be sure it’s at a height that’s convenient for all the members of your household. 
  • You’ll need a spade bit to drill a hole in the door where marked. Most power drills only fit bits with a shaft of up to a 3/8-inch diameter. 
  • Spade bits come in a variety of sizes. Be sure to select the size that will bore the diameter of the hole you’ll need for your viewer. Your viewer’s installation instructions will provide the size of the hole needed.
  • This door is fiberglass but if it were wood it could splinter. To keep from splintering the wood, start drilling slowly from the exterior side of the door first, and stop when the tip of the bit sticks through the interior surface. 
  • Take the bit and line it up with the edge of the door and wrap tape around the bit’s shaft to mark the correct depth for drilling the hole. 
  • Drill at a 90-degree angle until the tape line is reached, then use the pilot hole you just created to drill back out from the interior side to complete the hole. 

Tip: Using a step ladder will help you maintain a 90-degree angle.

  • Door viewers usually consist of a lens and a barrel. The lens is the part with threads on the outside. The barrel is the part with the threads on the inside. 
  • Insert the lens into the hole from the exterior side of the door. Then, insert the barrel into the hole from the interior side and hand-thread the viewer together. 
  • Apply a bead of silicone sealant around the lens to help seal out moisture if you don’t have a storm door or overhang. 
  • Tighten with the tool provided, or you can use a coin. The viewer should be flush with the door and snug.