Installation Guide

NOTE: Note, we recommend use of a professional for installation if unfamiliar with walking on roofs. We assume no responsibility for any injuries during installation of any Avalon Manufacturing product.
The following instructions are for installing a standard uncut A or B Unit.  If you ordered a pre-cut unit skip the cutting a Critter Quitter® section.

Cutting A Critter Quitter®



Closeup of pitch and screw guide lines

Critter Quitters® come with 3, 6, 9, and 12 pitch guide lines built in. (In degrees this is 14, 26, 37, and 45.) This makes cutting a Critter Quitter® to fit your roof easy by simply following the nearest pitch line when cutting.

To fit your Critter Quitter®, simply follow these instructions. You will need a tape measure or ruler, and a sawPlace the unit on your vent with the pitch lines heading toward the back of the unit to follow your roof.

  1. Place the unit on your vent with the pitch lines heading toward the back of the unit to follow your roof.
  2. Measure the gap between the bottom of the front of the unit and the roof.
  3. Measure that same distance on the back of the unit and mark that distance.
  4. Cut to the nearest pitch line, or use the line as a guide to cut in-between lines.

Cutting will require a handsaw or a miter saw. If you are using a miter saw that is 10 inches or less you may have to cut the unit partially with the miter saw and finish with a hand saw. Use the angles in the instructions to set up your miter.

Installing A Critter Quitter®

  1. After you have cut your Critter Quitter® to fit your roof install the four screws into the unit prior to climbing to your roof. These need to be in holes evenly around the unit. Also note that the two rows of holes in the back of the unit are higher than the front. This allows for roof interference of your screw driver. You can use the lower holes if you have a short vent or either of the two rows if your vent is tall enough.
  2. Place the Critter Quitter® over the vent and flashing. 3 and 4 inch flashing will fit snugly and may require some gentle shaping of the soft lead flashing to get it into the unit. The small 2 ½ inch flashing will require you to set the unit over the vent and work the screws in evenly to allow adjustment of the Critter Quitter® so that is directly centered over the vent inlet.
  3. Tighten the screws using a manual or electric driver evenly. They are self tapping, so they will draw themselves into the vent pipe. Continue to tighten until the screws are all the way in. Make sure you put some pressure on the screw as you tighten it so that it will pull itself into the vent material. NOTE: The material of a Critter Quitter® will strip easily; it’s only designed to guide the screw through the flashing and into the vent. So take care not to over tighten.
  4. Each Critter Quitter® has dimples that run the length of the unit. These indicate where the unit is thick enough if another hole location is needed or the hole strips out. Simply drill a 1/8 inch hole at the appropriate dimple and install your screw.
  5. Confirm that your unit is over the inlet to the vent and your installation is complete.

NOTE: Installation on Iron Pipe. Some older homes have iron pipe as their vent material. The screws will not penetrate this. On metal pipe simply hand tighten the screws evenly until they snug up against the pipe. Do not over tighten as the plastic will strip out and you will have to drill another hole location.

Removing A Critter Quitter®

In the event that you need to access the vent for plumbing work, simple back the screws out and slide the unit off. When finished replace and re-tighten the screws.


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