How to Apply the Top Cap to a Roof

Top caps are installed on rooftop vent openings. The purpose of a vent cap is to prevent birds and other animals from accessing the opening, and to prevent water from rain or snow from entering the vent. Most top caps are installed using a simple system of retaining screws. It's important to make sure the cap is secured tightly, or else the wind will likely blow it off of the roof and leave your vent stacks exposed.

Ladder
Tape measure
Top cap
Drill with screwdriver bit
Screwdriver

Instructions

- 1
  Use a ladder to access the roof and locate the vent stack that you want to cap. The vent stacks are usually exposed sections of pipe.
- 2
  Measure the diameter of the pipe using a tape measure. This will identify the size of cap needed for the job. Purchase a vent cap that matches the diameter of the pipe.
- 3
  Place the open end of the top cap over the pipe and slide it down as far as possible.
- 4
  Insert the retaining screws that came with the cap into the holes on the bottom of the cap. There will likely be four or more screws with a matching number of holes.
- 5
  Tighten all of the screws into the cap using a drill. Press hard on the screws as you tighten them, to ensure that the screws bite into the vent stack.
- 6
  Grab the top of the cap and pull it gently from side to side to make sure the unit is securely in place. If there is any movement when you pull, tighten the screws further by hand using a screwdriver.

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