How to Keep Insects, Rodents, and Other Pests Out of Your House

The best defense is a good offense.

As a homeowner, few things are as intrusive and unpleasant as having pests enter your house. Not only are they a nuisance, but they can cause significant property damage and can pose health risks. Fortunately, there are many proactive steps you can take to prevent pest infestations before they begin. Here’s a step-by-step guide on how to set up a protective shield around the perimeter of your house. I’ll cover common entry points in the exterior and interior of the house, and what you need to do to keep pests out.

Materials Needed

The Exterior: Basement, Foundation, and Ground Floor

This step involves a careful and thorough search around the ground floor of your house with a caulk gun and some caulk (see here on how to use a caulk gun). Look for any small holes and cracks that pests can squeeze into and enter your home. Walkout basements, crawl spaces under porches and decks, and exposed concrete or cinder block foundations are common entry points. Also check around any additions that were later built onto your house. Over time, small gaps can appear between the main house and the addition (I’ve had yellow jacket wasps enter the basement this way). Fill these cracks with caulk to keep pests out, and also to keep the cracks from getting bigger.

Diagram showing a crack in basement foundation in beige arrows sealed with caulk
Seal cracks in your basement foundation with caulk.
Use caulk to seal small gaps that appear between the main house and any built-on additions.

The Exterior: Fireplaces and Mixed Material Facades

Fireplaces are well-known entry points for pests as they are often constructed out of different material than the rest of the house. Modern and trendy architectural designs also have homes built with multiple materials for the facade (such as a mix of vinyl and brick). Any change in material can easily cause gaps and holes to form over time, which pests will quickly spot and exploit (I’ve had mice try to enter my house this way – look at the picture below!).

Copper mesh in a hole in a basement foundation preventing a mouse from entering a house
Fill holes near facade material changes with copper mesh or rodent fill fabric to keep mice and other pests out.

These gaps and holes tend to be too large for just an application of caulk, so use the Copper Mesh for Pest Control or the Rodent Control Fill Fabric. They both work great at keeping rodents and other pests out – it just depends on the specific situation and exact nature of the hole as to which will work better. Thoroughly stuff the holes with them. I add caulk to the mesh or fill fabric before stuffing it in the hole so it securely stays in place.

Copper mesh filling gaps in vinyl siding on a house
Fill gaps near facade material changes with copper mesh or rodent fill fabric to keep pests out. Here, a brick fireplace converges with vinyl siding, and both meet at the concrete basement foundation, resulting in noticeable gaps in the exterior of the house. These were filled with copper mesh and caulk.

The Exterior: Appliances and Utility Lines

Appliances are notorious entry points for pests. They can be located outside the house (such as air conditions) and need electrical wiring and piping heading into the house, or be located inside the house (such as clothes dryers and sump pumps) and need piping and ventilation heading outside the house. Either way, use caulk and copper mesh to provide a barrier to these entry points, as shown in the below picture. In addition to pipe openings, caulk and seal the protrusion in the facade of the house too.

Copper mesh enclosing the drainage pipe of a sump pump
Cover piping from sump pumps and other appliances with caulk and copper mesh.

You should also replace the dryer vent covering if yours is an older model and openly vents to the outside without any covering. Newer options, such as this one, have screen covers specifically designed to keep pests out:

Be sure to thoroughly inspect after any work is done to the utility lines feeding your house (such as electric or gas lines). For example, the local energy company supplying natural gas to our house recently replaced the gas pipe coming into our house (changed a black iron pipe to a galvanized pipe for extra corrosion and rust protection). They punched a sizable hole in the vinyl siding of our house, and of course left it wide open. I went afterward and filled it with copper mesh to keep pests from discovering a potential entry point.

The siding around a gas pipe coming into our house was left open and exposed after utility work was performed. This should be filled with copper mesh to keep rodents and other pests from finding a potential entry point into the house.

The Exterior: Garage

Garages, and specifically garage doors, are one of the most common entry points for pests. There are two likely locations on your garage door where pests will enter. The first is the rubber strip at the bottom of the garage door (pictured below). Over time, the rubber can dry out and become brittle – causing it to crack. Once it starts to crack, the rubber strip will not form a good seal with the garage floor. Replacing the strip on the bottom of the garage door will create a better seal with the garage floor, preventing rodents, and even garter snakes, from entering the garage this way.

Opened garage door with garage door rubber bottom highlighted by blue arrows
Replacing cracked or damaged garage door bottom rubber strips can keep pests out.

Helpful tip: I even stuff a little bit of the rodent control fill fabric in the ends of the o-ring of the garage door bottom rubber strip, as shown in the picture below (mice often test the ends of the garage door):

Rodent control fill fabric stuffed into a garage door bottom rubber strip
Stuff a little bit of the rodent control fill fabric in the ends of the o-ring of the garage door bottom rubber strip to further deter pests.

The other location where pests might enter are cracks and holes in the garage floor where the garage door meets the floor. These gaps can be large enough for rodents and other pests to slide under. Fill these gaps with specifically designed crack sealant (I use Sikaflex Crack Sealant), as shown here:

Hole in a garage floor sealed with caulk
Rodents and other pests can enter through gaps in the garage floor where the garage door meets the floor. Fill these gaps with specifically designed crack sealant.

The Exterior: Window Screens

Flying insects, such as bees, flies, and wasps, can easily enter a house through the sides of a window if the window screen is broken or has holes. Inspect all windows and their screens, and replace damaged or broken ones with new DocaScreen Fiberglass Window Screens.

The Interior: Attic

Attics have a surprising amount of ventilation – primarily letting rising hot air escape out of the house. Most commonly you find roof vents and/or wall louvers (also called gable louvers). Since these ventilation points allow access to the outside of the house, they are usually equipped with a screen (same as a window screen) to keep pests from entering the attic. Periodically inspect these screens to make sure there are no hole or punctures in them that could turn into a pest entry point.

Attic wall louver covered in black mesh
Wall louver located in the attic. Inspect the screen mesh for holes and punctures, and replace the mesh if any are found.

The Interior: Professional Pest Control Spray

In addition to all these steps, I would also highly recommend hiring a professional pest control company to service the interior (and exterior) of your house on a quarterly basis. The main reason is that the spray they use contains a chemical called bifenthrin. It is highly effective against all sorts of insects and pests, such as ants, moths, beetles, mites, spiders, ticks, yellow jackets, flies, and many more. I can personally attest that the bifenthrin-based spray the pest control company uses that services our house has almost completely eradicated household spiders that inhabited our basement in large numbers. It also was the only spray that resolved our yellow jacket infestation.

Be vigilant and monitor for entry often!

You’ll want to regularly walk the perimeter of your house and inspect common pest entry points. Whenever you’re outside – mowing the lawn, working on the garden, or playing with the kids – take a quick moment to look for signs of intrusion and to check on caulking and other preventative measures.

As the seasons change, so too will the pests that try to enter your house. Flying insects thrive in the warmer spring and summer months, whereas rodents tend to infiltrate in the colder fall and winter months.

Always be proactive: the best defense is a good offense!

Did you find this guide useful? What else do you do to keep pests out of your house? Let me know in the comments below!

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