If you have overhanging trees textured walls or anything that would let a rat climb on your roof then you should have aluminum screens installed on all your soil vents.
Roof vents and rats.
Your best bet might be to extend the duct a few feet above the roofline to make the vent inaccessible to rats.
Use a heavy grade of steel wool copper mesh or metal scouring pads to fill cracks and holes in exterior walls.
Rats can easily climb pipes rain spouts cables and other vertical objects where holes can provide an entrance to your home.
One common style of vent that is located on the roof is commonly called a j vent.
Caulk all exterior wall cracks.
Chris cudmore oct 24 13 at 18 29.
I actually don t think this can be done legally.
These entry points need to be sealed in order to prevent rats from entering the structure through roof vents.
Especially on a roof where you will have difficulty getting up to clean it.
Rats climb down and get into your plumbing system and get into your home through the toilet.