Rats in the Attic can be quite a problem not only from a peace of mind standpoint, but
also from a construction and health viewpoint. They are able to very quickly populate a
given area and cause tremendous damage to a structure. They are prodigious chewers
and have been observed chewing everything in an attic space from duct work to
electrical wires, water lines to stored items. Rats do not have bladder control, so they
are continually excreting while moving along through their lives. This urine trail is
loaded with pheromones that each rat uses as an easy way to find its way back to the
place it started. Other rats are also able to detect this odor and use it to find suitable
housing. Along with the urine issues come the flip side of the coin--droppings. A small
population of rats, in very short order, can accumulate a huge amount of droppings that
left unchecked can result in some serious health issues.
Copyright Wildlife Ranger 2013
The Roof Rat (Rattus rattus). We do more rodent
work in Orlando than work for all the other species
of nuisance wildlife combined. We have a tremendous
rat population in Orlando and the rule of thumb here
is that any home five years of age or older--has them,
has had them, or will have them. They have mastered
the art of gaining access to our structures and then
carving out quite a happy life from the unused
portions of our homes. The two most common rat
species found in Central Florida are the Roof Rat
(Citrus Rat, Black Rat) and the Norway Rat (Brown
Rat). The main difference between the two, for our
purposes, are that the Norway Rats tend to stay at
ground level where the Roof Rat will typically climb
as a means of gaining entry to shelter. Once inside the
attic or crawlspace rats will typically use the area for
sleeping, mating, playing and will exit nightly for a
food and water source.
• Rats are typically nocturnal, although it is not terribly uncommon to observe them
out in daylight hours. They are omnivores and will feed on nearly all food items. In
our area, citrus is a favorite as it is a one-stop-shop providing both a food and
• Life span in the wild is approximately one to two years (up to four in captivity).
• Home range is typically shorter than a few hundred feet from the nesting site.
• Adult rats can reach a length of 16 1/2". Females are capable of producing three
to five litters per year, consisting of one to sixteen offspring.
• Baby rats are born blind and hairless but are capable of producing their own
litters by as little as twelve weeks of age.
Noise: This is usually the first sign that shows the homeowner that something may not
be quite right in the home. The noise can usually be detected in the small hours of the
night, when the house is typically more quiet, and while all the humans in the house
are drifing off to sleep--the rodent population is just waking up to go do some
shopping and restaurant-hopping in the neighborhood backyards. The most common
time to hear this activity is after midnight (while the rats are heading out) and just
before dawn (as the rats are heading home after a night of partying). Some exceptions
apply, but this holds true in most cases.
Structural Damage: As noted above, rats will chew into any constructed surface to
gain entry to the structure. Most construction techniques used by the home builder
do not limit these issues as the contractor building your home is concerned with
water-tightness and not animal infiltration. Rats only need an entry point a little
smaller than the size of a quarter to make their way in and will often exploit weak
areas of construction such as eave gaps and poorly done soffit. They are able to
chew their way through most any material found in your attic and usually do so.
Droppings: Urine and droppings left behind in your attic are a real concern. After
a population has been evicted it is highly recommended that a proper attic clean
up be conducted to make the home safe and healthy.
Recurrence: The pheromones left behind by the rats as they travel will invite
others to investigate the area and is another very good reason to conduct an attic
decontamination. Once you have had rats in your attic you are more likely to have
others attempt to reach the same spot. A thorough exclusion, done correctly,
should prevent re-entry through the original entry points.
Typical chew-hole entry in eave gap.
"Sleeping" rat, dollar bill used for scale.
Exlusion: Repairing the entry points and ensuring that the home is properly excluded
is the key to solving the issue permanently. Rat repairs should be made using only
industry accepted materials and procedures as the persistance and intelligence of the
animal will ultimately undo any effort that is not completed 100% to standard.