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How to Control Rodents in Your House

British Columbia has a fair share of rodents like marmots, voles, chipmunks, gophers, and squirrels, but the most common rodent infestations in Vancouver come from Norway rats, roof rats, and the house mouse.

Signs of Rodents in the House

Do not ignore a rodent infestation. You need to act at the first signs of rodent activity.

  • Gnawing. A rodent’s teeth grow continuously, so they must gnaw on things to keep this growth in check. As you might expect, this leaves rather damning evidence. Look for gnaw marks on things like garbage cans, fences, food containers, and under porches. Squirrels sometimes chew through roof vents or attic louvers to gain access to the attic.
  • Runways. Mice and rats are creatures of habit and will follow the same route between their nest site and food and water uses. After repeated use, these paths develop dark, greasy rub marks that are accumulated from the oils and dirt on the rodent’s fur. Runways usually follow along manmade edges like baseboards.
  • Sounds. Squirrels, mice, and rats all make similar sounds if they’ve made it into your house; rustling or scurrying noises. The bigger the rodent, the louder the sound will be. Squirrels may also make rolling noises, as they roll nuts and acorns around. Pay attention to when the noise is being made. If it occurs during the day, it’s probably a squirrel. If you hear it more at night, it’s more likely to be a mouse or rat, since they are nocturnal.
  • Vocalizations. Both mice and rats communicate at a pitch that is undetectable to the human ear. However, if they are distressed, they may make squeaking or hissing sounds. Still, you are more likely to hear movement sounds than vocalizations.
  • Odors. When living in confined spaces like homes, rodents tend to produce an odor that is most often described as musky and resembling ammonia or stale urine.
  • Rodent Droppings. Look for droppings in areas that are not frequented by humans, like attics or basements. Droppings are found in the largest numbers near nesting sites.

DIY Rodent Control

Most of our customers have tried some sort of DIY solution before they commit to professional rodent control. Rodent repellents like over-the-counter poison, sonic emitters, mint oil, radios, lights, wolf pee, and ammonia-soaked rags are not effective.

The best rodent control homeowners can do is prevention. Rats and mice are looking for food, water, and shelter. Removing these resources helps immeasurably.

Eliminate Rodent Shelter

  • Keep grass trimmed
  • Trim bushes and trees
  • Remove clutter or rubbish outside your house
  • Move bushes, shrubs, and mulch from the foundation of the house

Remove food sources and water

  • Secure garbage cans
  • Repair leaks from pipes
  • Empty standing water
  • If you feed pets outside, bring pet food indoors
  • Clean up spilled birdseed from birdfeeder

Keep them outside

Rats and mice can fit through tiny holes and chew through most home construction materials.

An established rodent population cannot be controlled with repellents or deterrents. If possible, seal any potential gaps. This is difficult. Rats and mice can fit through tiny holes and chew through most home construction materials. The key is to literally check every square inch. Rodents usually have more than one entry point. Once they find a suitable location to nest, they probe weak spots to create new entry holes.

Once access is established, rats leave scent/pheromone trails that are easy for other transient rats to pick up and follow. For this reason, structural rat problems are literally never-ending until you effectively pest-proof the access points, thereby cutting off the ‘flow’ and isolating your populations.

Most Common Rodent Entry Points

The Roof

This is the most common rodent entry point, especially for roof rats!

If you hear scratching or squeaking coming from the roof or attic, your first task is to head on up there and check out every square inch. If your roof is too high, or too steep, then please hire a professional.

Common rodent access points on a roof:

Gutter lines

Gutter lines are one of the most common rat entry points.

The fascia (the board the gutter line is attached to) degrades quickly due to frequent exposure to moisture. Homes are built with a gap between the fascia and the roof decking for moisture control. There can be small gaps/seams at the inner and outer corners.

Rats will rarely pick a point off a flat board and start chewing, instead, they like to identify small gaps and flaws and exploit them.

At Critter Control Canada, we check every inch of the gutter line, paying special attention to corners. We lift up the shingles to see how the roof decking meets the fascia. Signs of a roof rat access point is gnaw marks, droppings in the gutter nearby, and black grease marks from the rats’ fur.

To exclude a gutter line, simply cut long strips of steel mesh (usually 3-4″ wide x 4′ long) and screw them into the gutter line to cover the gaps. You might have to do a small section, or you might have to do the entire line. If there is any gap at all, we would recommend addressing it all.

Soffit angles

Soffit angles are where the soffit line of one roof section meets the shingles of another. These are difficult-to-reach places during construction, and sometimes there is little holding the soffit in place.

A variety of nuisance wildlife can gain access to the attic from the soffits. Raccoons will get in the angle and use their head to try to knock the soffit out of place – we hardly see a house with roof access in the Lower Mainland without dents in their angles! If it is an active access you’ll notice it easily, if it looks tight and clean then just give it a good push to test how strong it is. Not every soffit angle needs to be excluded, but if it is flimsy then you should address it.

These can be tricky to pest-proof. The key is to cut steel mesh the same width as the soffit line and about 4′ long. Tack it onto the line, run tight into the angle, and then screw it down onto the shingles. Pick up some roof sealant to cover your screws to be safe, but usually, you’ll be under the cover of the soffit line above so leaks aren’t much of a concern.

Take a good look at your finished product, if there’s more than a 1/2″ gap then you either need a bigger piece or just install some filler pieces. This doesn’t have to be pretty – you’ll hardly see it from the ground – but if you can pull it out of place then it likely won’t last. Don’t underestimate these things!


This is usually where people think the rats are accessing the roof, but it’s not as common as you would think. If there is no grating on the chimney hole then you have a few options. We usually cut a piece of mesh just slightly bigger than the opening and press it inside; the mesh will bite and hold with enough strength to be effective.

Plastic roof vents

Often overlooked, plastic vents are an easy access point for a variety of larger pests. Although they look sturdy from the outside, anything that squeezes underneath the overhang has only a plastic bug mesh to chew through. The best thing to do is to grab a flat nail-puller and gently pull the vents completely off the roof to expose the hole. If you don’t have an attic hatch, this is a great way to get a look inside!

Be careful here, depending on the state of the shingles how many nails/amount of sealant the roofers used, it might be better to leave the vent on and exclude it from the outside. This is achieved by simply screwing a strip of mesh directly into the vent, just so it blocks the 1″ opening at the bottom.

Other Places to Find Rodent Entry Holes

Tree trimming

Pretty simple; if you can see branches lying on your roof, you should cut them back. Use the 4-foot rule.


Take an initial walk around and check your walls from the ground up – there likely isn’t a random hole in the middle of the wall, but look anyway. Take note of any plastic vents or metal vents that might have screens missing or loose.


Holes in the foundation most often occur where the wood structure of the house meets the foundation. There might be an obvious hole, or it could be hidden underneath the siding.

If you can get your whole hand underneath your siding then you need to determine whether or not the siding is hiding weak infrastructure or not. The easiest way is to put on a glove and start feeling around. If you can’t find the top of the void then we would suggest excluding it. Fortunately, this is pretty simple. Cut some 3″ strips of mesh and give them a bend down the middle (the long way), then push it up into the void and let it expand, that’s it!


Seems obvious, but it is often overlooked. Give all your doors and frames a good look – if there is a noticeable gap you can either cover it with mesh or flashing, or there are rodent-proof door sweeps that can be purchased and easily installed. These could be hard to get depending on your area; the company is based in the US and doesn’t have a huge presence yet.


Rats love nesting under steps, and if there is a void with an exposed flaw, you can bet they’ll try to exploit it.

You can usually tell if this is the problem by simply inspecting the perimeter of the step. Look for trails, digs, and droppings. If you think rats might be under the step and there is an activity that corresponds to the interior, then you should assume there is an access point behind it.

Large wooden steps often allow access underneath with a little work – this is the best-case scenario. Get under there and inspect the exterior wall, you’ll see an obvious access point if it is there.

If there is no access – such as a concrete step – then you’ll have to do some trenching. Dig a 1×1′ hole around the perimeter of the step, and affix mesh from the step (just above the ground line) down into the trench, and then out, effectively creating an “L” shape. This can be tough if there are roots, but if it is necessary then you’ll just have to get through them. If you’re doing this with a concrete step, ideally you can get a hold of a concrete drill to affix the mesh. These can be rented for cheap, or we bet one of your neighbours has one. Punch a hole every foot and use concrete screws with washers to keep the screen tight to the step. This looks tidy and is as permanent as it gets.


Same deal as steps, but probably a little more common. If you think your deck is hiding an access point, you have a couple of options. If it’s high, crawl in there! If it’s low to the ground, you can pull up the boards close to the house and work that way – this often works!

if the boards are running perpendicular to the wall or you don’t want to risk damaging your deck, then you’ll have to resort to “L” trenching as mentioned above. This might seem like a big job, but it usually goes fast. It’s also something that your neighbourhood teenager is perfectly capable of doing for a few bucks.

How Critter Control Gets Rid of Rodents

Critter Control Canada specializes in rodent removal and control. Rodent removal begins with a thorough inspection to determine how severe the problem is. The more established rodents are, the more involved the removal process will be. After inspecting, our wildlife specialist will build a custom solution to trap, remove, and seal all entry points.

Rodent Traps

Based on the inspection, our wildlife specialist creates a strategic trapping plan to remove the rodents found in your home. Types of traps, placement of traps, and bait used in traps determine the effectiveness of rodent trapping.

Our wildlife specialist will ensure to use of the most efficient and safe removal process for your home. Though the standard trapping/removal duration is normally between 5 to 14 days, the trapping process may be longer if the rodents are well-established.

Types of Traps

Snap Trap

Snap traps are the typical mouse trap or rat trap. They have a small bait cup into which the bait is inserted, then you pull the metal lever back 90 degrees, and the trap is set.

Plastic Enclosed Rat Traps

These are very similar to generic snap traps, except they are encased in a hard plastic shell, and you use a lever on the exterior of the shell to set the trap. There is also an indicator for when a mouse is caught.

Live Catch Traps

These devices are unique in this list in that they do not kill the rodent; rather, they simply hold it until you can release it elsewhere. There are two main versions of live catch traps: metal cages, and plastic tubes, both of which are outfitted with trigger-operated doors. Metal cage traps are preferred as they are large enough that the captured mouse likely won’t get overly stressed out in the time it is detained.

Electric Traps

Electric traps work by luring rodents into a chamber and administering a lethal shock. They are gaining in popularity because they are one of the more humane options, killing mice almost instantly. They are also engineered to include a no-see, no-touch disposal procedure, and a light to indicate when a rodent has been caught. They are also designed to ensure that humans and pets cannot be shocked.

We avoid glue traps because they are inhumane.

Rat bait

Rat traps should be baited with enticing foods like bacon, peanut butter, oatmeal, or marshmallows and placed along areas rats are known to regularly travel such as adjacent to walls or in dark corners. Toxic options, such as anticoagulant baits, may pose hazards for small children and pets.

Successful household rat bait:

  • peanut butter
  • Nutella
  • raisins
  • nuts (stuck to something sticky)
  • bacon/grease
  • marshmallows

Remember, less is more! Put a small amount of bait on the trigger, and make the rat commit to the pan to get the treat.

Bait Stations

Although they might look like a trap, bait stations or bait boxes are not rodent trap. Bait stations contain solid, liquid, or paste rodenticides, and increase the effectiveness and safety of rodenticides. Bait stations have two holes one for entry and one for exit. After the rodents eat the bait, they leave it. Rodenticides should be used as a supplemental control option. If you need to use repeated use of baits, trapping and exclusions services are needed.

Rodent Exclusion

Rodent exclusion is the best rodent control method. The rats and mice got into your home. During the Critter Control free inspection in Houston and surrounding areas, our technicians identified all current and potential animal entry points.

After rodent removal, it is essential to repair any entry points in your home. Rodents leave pheromone trails, and other rodents quickly utilize those scent trails.

How long do rodent control services take?

It depends on how well-established the rodent population is and how many rats or mice are present. We get results in the first night or two, but typically rodent trapping takes one to two weeks.

Critter Control Canada offers recurring services to keep your home protected and under warranty.
In addition, Critter Control provides warranty options as well as an estimate for preventative services to keep your home free of future rodent problems

Dangers of Rodenticides

This should be first, but if you’re actually going to follow this guide, then you’ll have read this far. Regardless of how bad your problem is, poison is NOT the answer. Aside from the myriad of inhumane and environmentally degrading factors, the best result poison will get you is some stinking carcasses in voids you can’t access.

  • you can never tell how many rats hit the bait, whether or not they died, nor where they went after they did/didn’t die
  • rats will have to commit to the poison anywhere from 2-8 times over a couple of days to get a lethal dose if they die at all.
  • rats that don’t die can become resistant, and even become more likely to pass on diseases due to their compromised immune system
  • rats do not die peacefully, and they do not seek water and die outside. Most often they will die in your wall or floor and create a health hazard
  • rodenticides are responsible for countless secondary poisonings, from basic scavengers to birds of prey, and even larger predators like foxes, coyotes, and cougars
  • 10,000 children per year in the US are hospitalized due to contact with rodenticides
  • the list goes on… buck up and set a snap trap