Posted by: SherlockHomesSY | 7 Jan 2011

Common Complaints: Pests

Scientific RodentPESTS

– Vermin
– Rodents
– Birds
– Snakes
– Insects
– Spiders

Bugs, rodents, snakes, and other vermin like to live at the same humidity level and temperature we do.  We invite them in by our house cleaning habits, holes, and by feeding them the house.  The problem with these critters is they make us sick and sometimes make it hard to breath.  Some destroy things.

This blog post is more about how to effectively keep pests from getting in the house in the first place or limit their numbers, rather than how to get rid of them.  We’ll leave vermin removal to pest control experts.

This is the first of a 2-part blog post about pest complaints.  In this one, we cover rodents, birds, larger animals, and snakes.  In the next one, we’ll cover the creeps: insects and spiders.

Biology. Know your enemy!  To effectively defend against any kind of pest, you need to understand something about their biology and habits.  Thankfully, to live in a relatively pest-free home doesn’t require a PhD in bug-ology, bird-ology, rodent-ology, or snake-ology.  Introductory biology offered in high school is enough for most of us.  If nothing else, it teaches us when to call in experts.

Rodents. I’ve had to deal with bats, mice, and squirrels.  Others have dealt with rats.  Then there’s the occasional raccoon.  I’ve either heard or seen them is every part of the house.  Keeping these pests out is relatively easy.  The secret is to keep the holes through the side of the house small or non-existent.

Screens & Dampers. The general rule is to cover vent openings with 1/8-1/4 inch mesh.  These include the fireplace fresh air intakes, bath area vents, and crawlspace vents.  When air is power exhausted to the outside, such as with a dryer or rangehood fan, they are allowed to covered with a gravity damper.

Lookout for a damper that won’t close, for whatever reason. On just about every house, I see dampers that are warped, broken off, clogged with lint, or installed out of alignment.  When there’s a damper installed correctly at the exterior of the house, it isn’t important to cover it with any kind of screen.

Though I like the idea of and additional screen over a damper, some crazy builders install a screen over a dryer vent.  Great! The lint gets caught in the screen.  Now the damper can’t open.  Lint builds up in the duct.  First, clothes take a lot longer to dry.  It’s not unheard of for this lint to catch on fire!  The building code is quite explicit about not covering a dryer vent with a screen.  However, some people who won’t “get it” think I’m crazy instead, because the builder said it was okay!

Building Holes. Sometimes rodents or weather creates unintended holes.  One of my favorite stories is about squirrels who found their way into my attic to chew the electrical wiring.  It happened, in part, because the soffit started falling out.

It helps to keep windows and doors closed too.

Air sealing and air leaky house not only reduces insects, but it will also help keep rodents out too.

P-Traps & Plumbing Vents. There’s no requirement to cover plumbing vents, because in theory, rats and mice don’t travel through filled p-traps, such as you see under sinks.  However, if you buy a house much bigger than you need or the house sits empty for a long time, such as a foreclosure, the p-traps dry out.  Here come the mice!  Sewer rats will come up through dry toilets.  Rodents that fall out of trees can come in through plumbing vents in the roof.

Sonic Control. “Research reports in scientific journals have demonstrated that ultrasonic pest management devices do not kill, repel, or eliminate insect or rodent pests.  Accordingly, they are of little value in the professional pest management industry.” –Georgia Pest Control Employee Registration Manual, Georgia Department of Agriculture, Georgia Structural Pest Control Commission, Revised 1 July 2006.

Birds & Larger Mammals. The methods used to keep rodents out are usually effective in keeping fowl and bigger animals out too.

Snakes. I hear snakes get into houses, and I’ve seen pictures in professional magazines.  I’ve never encountered one—even in a crawlspace.  I suppose they’re coming in after the rodents.  Keep the rodents out and the snakes will probably stay outside too.


We’re not pest control experts.  We do our best to help you recognize opportunities to avoid them.  Some of us even have some training in inspecting for wood destroying organisms in Georgia.  We’re experts on what pest control features are in the building code.  However, when pests invade, call a local, licensed and professional pest control expert.

When I want pest control information on-line, I ask the pest control expert!  His blog is fun to read and easy to understand!  As such, he has the honor of being on our blogroll!

In Conclusion

Have I made our point yet? Air sealing goes a long way toward limiting pests.  Screen required openings through the building too.


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