Rat Inspection - How Are They Getting In?
This is the key - you will never solve your rodent problem
in a building until you can find out how the rats are
getting into the building in the first place. They can get
in via so many areas - they only need a hole the size of a
quarter, or a gap that is about 3/4 of an inch. Heck is
seems like even 5/8 inch is fine. Check every vent - gable
vents, roof vents, ground-level crawl space vents, even the
laundry vent. Check all doors and windows. Check every part
of the roof, especially the fascia, and wherever an eave
meets the roof. Check all roof lines. If you have a tile
roof, you've got a TON of entry spots. Check plumbing
stacks, air conditioner chases, power line enry points,
basically, EVERY SQUARE INCH OF THE HOUSE.
Here are four small examples of easy-to-spot rat entry
points. In the upper-left, there's a hole that's been chewed
out at the end of a gable intersection with a roof. Roof
edges, and anywhere where roof meets roof is a rat entry hot
spot. In the upper-right, a very obvious chewed-open ridge
cap plug. The open ridge cap goes right into the attic, of
course. This is a popular rat and mouse entry point. In the
lower-left, it's some wires going into a gable vent, and
only a flimsy screen blocks access. You can see how easy it
is for the rats to chew through and slip into the attic. In
the lower-right, it's a chewed out hole by a soffit vent.
Never mind that the cover is in place, rodents can gnaw a
hole open in the wood. Read about What
can rats climb?
If you're not experienced with ladders, and you MUST use
ladders to check all of the critical roof points, then be
careful! Wear a safety harness, and have a spotter. Same
with working on the roof, which you must do. An experienced
guy like me can scramble all over a steep roof with no
trouble, but I wasn't that way as a beginner. When you go in
the attic or under the house, wear a respirator, and maybe
even a protective suit. I also always wear gloves, and a
head lamp is very helpful in dark attics and crawl spaces.
WHY IS THE INSPECTION IMPORTANT?
You have to find out how rats are getting inside the
building. This is absolutely crucial! Those rats are
entering your home and attic somehow. You will NEVER solve
your rat problem unless you find ALL the entry points. Every
single last one. One little failure, one missed spot, and
you will have rats in your attic or house forever. You must
inspect the whole structure, from the ground up, including
all portions of the roof, and the plumbing system. Check
vents, eaves, roof joints, plumbing stacks, AC chases, the
chimney, EVERYTHING. You must be completely thorough. An
intimate knowledge of rat behavior and building architecture
helps a great deal. Know what signs to look for - brown
staining and grease at entry points, gnawing, etc. Also,
inspect in the attic, where you will see rat trails that
will help you identify entry points, and you'll spot rat
damage that you'll want to fix, such as gnawed wires or
The above photo reveals a pretty easy rat entry point. You
can see what happens. Rats love to find small holes and
climb pipes and wires up walls and into the attic. But most
entry points are not this obvious or easy to reach.
Sometimes rats can get in under the house, even by digging.
Read about Do rats dig holes? Do
they burrow under houses? How deep?
IT AINT ALWAYS EASY
I often have to crawl in very tight spots in order to find
all the rat entry points. I also, more importantly, have to
know exactly what I am looking for, and why. Follow the
trails of grease marks and droppings. Use an ultraviolet
light to see rat urine glowing in the dark. Sniff around.
Think like a rat. Well, I don't mean that in some lame
redneck trapper way, I just mean that you have to be willing
to carefully inspect anything a rat might be able to use,
and understand rat behavior. There are also many little
tricks, such as getting a full understanding of where the
rats are making noise. Click here for more info about rats
making noise at night, and you can gain some clues
about the entry areas.
THE SAME APPLIES TO MOUSE REMOVAL
Although I wrote this site with rats in mind, such as the
Roof Rat and Norway Rat, the same principles apply to other
rodents, such as the house mouse. Mice behave very similarly
to rats, they're just smaller. Email me if you have any
questions about inspecting a house for mice. In short, they
can get into much smaller holes, like the size of a dime, or
a 3/8 inch gap.
Read more articles about rats:
Do rats destroy insulation
in an attic?
Do rats chew on wires? Why?
What can rats chew through?
Will a rat chew through the