What Size Hole is Needed to Install the 2-Piece Polypropylene Trailer Vent

Updated 09/25/2013 | Published 09/24/2013

Question:

I am installing this vent on my enclosed car hauler, but the trailer wall is thicker than the vent will accommodate. If I drill a 3 inch hole the vent will have a gap in the wall between the inside round piece and the outside half moon piece which could allow moisture to get inbetween the wall and outer skin of the trailer.

asked by: Nikki

Expert Reply:

Installation of the 2-Piece Polypropylene Trailer Vent, # HMAV2-AVT2, requires a 3 inch diameter hole when installed in a trailer with standard trailer wall thickness, 1-1/2 inches thick or less. This is the case for most enclosed trailers, but since your trailer wall is thicker than 1-1/2 inches you will need to use an appropriate length piece of 3 inch inside diameter (ID) PVC pipe to accommodate the thicker wall.

The outside diameter (OD) of the 3 inch ID pipe will then dictate the size hole that you will need to drill. In most cases schedule 40, 3 inch ID PVC pipe will have a 3-1/4 inch OD but that may not be true in all cases, so you should measure the outside diameter of the pipe you choose to use.

Once you have a piece of pipe to use, with a 3 inch inside diameter, use a hole saw to drill the correct size hole in the inside and outside wall of the trailer. Next, measure the thickness of the wall and cut the pipe to the correct length plus about 1/4 inch to install in the wall. You can then slide the inside part of the 2 piece trailer vent into the pipe and secure it on the inside of the trailer and then mount the outside part of the vent over the pipe on the outside of the trailer.

expert reply by: Robert G