5 Best Ways to Seal Up Chipmunk Holes For Good

hungry chipmunk eating peanuts

Everyone knows mice and rats are a problem. They gnaw on walls and wires, leave droppings on floors and in cabinets, and just cause a whole lot of good ol’ fashioned destruction. But what about chipmunks? Can they be as destructive as any mouse?

Chipmunks typically chew holes in attics, chimney chutes, basements and the siding of homes. For chipmunks holes up to 1/2in, seal them with latex or silicone sealant and use a backer rod if needed. Gaps over 1in can be sealed with expanding foam while using welded wire screens for larger holes.

If you’re looking for the best material to fix chipmunk holes for good, this article is for you! But before we start talking about how to stop chipmunks from getting into your home, let’s learn a little bit about why chipmunks are a problem and what the signs of their damage are.

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Why Are Chipmunks Such a Problem?

Chipmunk Looking For And Eating An Almond And A Cashew Nut

Chipmunks will chew holes into food containers, build nests in your chimney and unoccupied spaces, and eat vegetation in your yard. They also build large and destructive tunnels to live in, which can really mess with the look (and stability) of your lawn.

Unlike their squirrel counterparts, chipmunks make their homes underground and thus, stay on ground level most of the time. According to the University of Georgia, chipmunk tunnels can extend up to 30’, and colonies may consist of 20 individuals. That’s a lot of rodents living in your yard, looking for food and chewing on your walls!

Chipmunks may enter homes through convenient cracks or holes in order to access food such as nuts, grains and seeds (their favorite foods). They may eat birdseed, or even pet food if it’s in a convenient spot, and they particularly like eating dog food. Chipmunks have even been known to snack on flower bulbs and the bark of trees or shrubs, ruining landscaping and gardens.

When chipmunks build their homes they can tunnel under lawns, killing grass and causing areas of the ground to become unstable or look uneven. They may also tunnel under your flower and vegetable garden, destroying roots and making your garden beds unusable.

If they decide to nest in your house, they’ll often choose somewhere people aren’t to make their homes (like crawlspaces or chimneys), gnawing on materials in order to make nests, and carrying disease just like other rodents do.

How To Identify If You Have A Chipmunk Problem

The most obvious way to know if you have a chipmunk problem is by seeing them! Chipmunks reproduce quickly and you’ll likely see them out and about in your yard. You may also hear them inside your home as they build their nests and raise their young.

If you suspect you might have a problem, you’ll want to check for droppings, as well as gnaw marks on nut, grain, pet food or seed containers. You may also find leaf and plant material in places your don’t expect it, from building their nests or as they come and go from the outdoors.

If you check around the outside of your home, you may be able to see burrow openings in hidden areas like near logs or shrubs.

Per a National Park Service guide on rodent control, chipmunks tend to stay away from occupied areas of home. But, if you rarely enter your basement, attic, crawlspace, or you have an abandoned chimney that you don’t use, you’ll want to check it regularly for signs that chipmunks have moved in.

If you’re going to be away from home for a significant amount of time (such as you have a vacation home or cabin you only occasionally use), you’ll want to take steps to stop chipmunks from entering your home.

Why Do I Need to Seal up Chipmunk Holes?

Chipmunks scavenging for food

Filling up or covering rodent holes is an important step in preventing them from entering buildings and gaining access to spaces and food supplies.

You’ll also want to seal up any holes that could become chipmunk holes, to keep them from coming inside in the future. By making it difficult for chipmunks to access your buildings and food sources, you can discourage them from hanging around your property.

A study published in the National Library of Medicine assessed whether or not rodent proofing chipmunk holes actually had any effect.

Specifically, the researchers sealed openings with wire mesh (which chipmunks have a great deal of trouble chewing through) and found that rodent proofed houses were infested significantly less than non-proofed houses. This means if you take steps to discourage rodents, it actually works!

So, it’s important to fix any areas that chipmunks may use to get back and forth between your yard and building!

This could include areas like the chase on your chimney, holes near your siding and foundation or possibly exposed insulation near your attic or basement.

So – How Do I Seal up a Chipmunk Hole?

Ah, now to the fun stuff!

The first step is to conduct an inspection for any open hole in the outside walls, roof and foundation of your home, shed, or other buildings you want to rodent-proof (chipmunks can fit through even the tiniest of gaps, even as small as 1/4 inch!).

It may be helpful to look around on sunny or windy days. If you can see sunshine or feel air, there’s a good chance there’s a gap a chipmunk could squeeze through.

Chipmunks are tiny creatures that will use very small gaps and holes to their advantage. You’ll want to look for rodent holes, but also thoroughly check vents, spaces around chimneys and pipes, and gaps in foundations that may have spaces that could allow them into your home.

We’ll get into specific materials to use to later in the article, but to seal up a chipmunk hole, you need to completely fill in gaps or spaces with a material that a chipmunk will not want to chew through. Otherwise, you risk a reinfestation, as well as further damage to your home.

If you want to keep chipmunks away from your property altogether, I highly recommend you check out our piece on the 15 best chipmunk repellents – it’s a game changer!

Where Do I Find Chipmunk Holes Near My Home?

Since chipmunks are mainly ground-dwelling, look for holes that are near the soil and around your foundation.

Seal chipmunk holes where gas lines, cooling lines, electric cables, dry vents or cable TV lines enter the house. Crawlspace vents are another easy area for chipmunks to get into, especially if the vent has large gaps and is not covered by a fine mesh screen.

If chipmunks have easy access to a roof, they may also climb to enter the tops of chimneys, gaps in soffit, or attic vents.

If you have nearby branches, vines, or even powerlines running to your house, you’ll need to go above the ground to check for signs of chipmunks. Just like other rodents, chipmunks will use every opportunity to gain access to food and safe areas to nest.

The Best Things To Fill Up Chipmunk Holes With

There are a variety of materials you can use to plug up holes or gaps. You’ll want to find a strong material that a chipmunk doesn’t find appetizing (or easy) to chew through.

If you use wood or a foam backer rod such as the M-D Building Products 71480 1/2-Inch by 20-Feet Backer Rod, or small wood pieces to plug holes, for example, you’ll also want to use a sealant or metal mesh to discourage them from undoing all your hard work.

Here are some examples of materials that can help chipmunk-proof your spaces:

Caulk

If, during your inspection, you find a small gap such as an open seam around windows or doors, your best option may be a product like this Gorilla White 100% Silicone Sealant Caulk or the Sashco Big Stretch Acrylic Latex High Performance Caulking Sealant (both are waterproof and have some stretch).

This will allow you to seal the gap completely, by applying a continuous bead of caulk then smoothing it with your finger or a special tool like the Saker Silicone Caulking Tools-3 in 1. Even if the caulking you purchase is advertised as “stretchy”, you’ll want to keep an eye on it after it dries to make sure it doesn’t shrink and reopen the gap you were trying to fill.

Caulking is not great for filling large gaps or for large (or irregular) shaped holes. If you need to fill a seam that is larger than ¼ inch across, you’ll need to first fill it with something the caulk can stick to, such as a backer rod, mesh, or rodent barrier cloth. For larger holes, you may want to install a wire screen instead or consider using expanding foam.

Caulk is best for small gaps between boards or along doors or windows. To seal large holes, you’ll need to select a different option from our list below.

Personally, I really like caulking small gaps especially since it’ll probably blend in well with your home our structure.

Cement Sealant

For gaps in foundations, chimney or brickwork, you’ll need a specific sealant that will adhere to masonry and concrete.

Cement and mortar sealant (such as the Dap 18021 Concrete and Mortar Watertight Filler and Sealant) is a solution that can help prevent chipmunks from accessing crawlspaces and chimneys. It is applied in the same manner as caulking, by squeezing the sealant from a tube then smoothing it into the gap.

Unfortunately, cement sealant comes with the same limitations as regular caulking. To fill anything more than ¼ inch, it should be used with a backer rod or either rodent barrier cloth, or replaced with a metal mesh for larger gaps. It is also waterproof, but may shrink after application.

Cement sealant has many of the same benefits as latex or silicone caulking, but also the same limitations. It’s a good choice for small gaps that abut masonry or foundation spaces.

Galvanized Metal Mesh

If you’re not a caulker, then you better be a mesher! Honestly, nooo idea what that means. But, try some metal mesh!

Metal products are a great option to use if you’re worried about chipmunks rechewing old holes or covering large holes. Utilize 1/4-inch welded wire like the SATINIOR 2 Sheets 1/4 Inch Wire Metal Mesh or wire mesh to close off vents and holes, or incorporate steel wool or copper mesh with sealant or caulking to better weatherproof gaps.

For welded wire screens, you’ll want to have a few things handy to make the work easier.

First: Wire cutters like these IRWIN VISE-GRIP Diagonal Cutting Pliers are necessary to cut the piece to size (you’ll want it slightly bigger than the hole so there’s space to attach the edges).

Second: You’ll need a staple gun (check out this Upholstery Staple Gun Heavy Duty) meant for wood; it will make short work of securing the screen piece so it cannot be easily pulled off by rodents.

Metal is the best choice for large gaps. With the right tools, it will be hard for a rodent to reuse the hole, and chipmunks will be unable to chew through it.

Expanding Foam

Loctite TITE FOAM Insulating Foam Sealant is a great solution for holes that are too large for caulk or sealant, but when you don’t want the hassle of cutting out and securing metal pieces.

It can also insulate a hole using several inches of material, which is great for deep holes in exterior walls where you may want to avoid heat loss.

Expanding foam is really easy to apply. Each can will typically come with a straw applicator that can be used to direct the foam into a specific area. It bonds easily with most types of materials, and it seals out moisture as well as air.

Foam is best for holes around 1 inch that need to be waterproof and insulated. It dries quickly, but without other materials to discourage rodents, chipmunks may chew through it again.

Rodent Barrier Cloth

Rodent barrier cloth such as the XCLUDER 162758A Rodent Control Fill Fabric Large DIY Kit is a fiber and steel blend that does a great job of filling holes and discouraging chipmunks from chewing.

It can be used for even large gaps, and it’s a good option if you’re looking to plug a hole but don’t want to use a product that may contain lots of chemicals.

However, it does not do a great job of insulating or waterproofing, so you may want to combine it with expanding foam or some other type of sealant to cover all your bases.

Sealing Up Potential (And Old) Chipmunk Holes

chipmunk on tree perched

If you find holes that you think chipmunks may get into in the future, you’ll want to seal them up quickly before they become an easy access point for critters.

If you conducted a full inspection of your home, you likely found all sorts of gaps that a chipmunk could squeeze through. Here are a few ways you may make your home even more chipmunk-proof:

Close Up Vent Dryers

Attach a wire screen to the bottom of a clothes dryer vent if the vent is easily accessible from the ground. This will make sure chipmunks CAN’T climb up it.

Check out the section on welded wire mesh screens to find great, permanent options. You won’t be able to staple the screen to the vent without causing damage, so consider using a glue or caulk.

Seal Downspouts

Chipmunks will often build nests in rain gutter downspouts. This can be a huge problem when water begins to back up your downspouts and pour over the side of the gutters, causing pooling around your foundation.

Exclude chipmunks from rain gutter downspouts with wire mesh coverings.

Stop Up Door Gaps

Spaces along the bottom of doors can give chipmunks just enough space to squeeze in and out of your house. Use door sweeps or kick plates on bottoms of doors to seal any holes and stop rodents in their tracks. Here’s a tip: if you can feel air moving under the door, you likely have enough space for a chipmunk to get in.

Seal Around Pipes

It’s rare that there is an airtight fitting of pipes and vents. For piping that penetrates exterior or interior walls, you’ll need to install some extra hardware to stop chipmunks from getting in.

Install a two-piece escutcheon plate like the Uxcell Wall Split Flange around pipes for a perfect, rodent-proof solution.

Close Off Chimneys

Chimneys are a frequent chipmunk nesting area, especially if it’s been a while since you’ve had it cleaned or lit a fire. Chipmunks can utilize trees and powerlines to access your roof, and will then scurry down the chimney to build their home.

Attach a Cone Top Chimney Cap with Screen on chimney tops to prevent chipmunks from climbing in. Or, call your local masonry to have them come take a look to make sure there’s no other cracks!

To Recap What Method To Use For Each Chipmunk Location

For gaps around ¼ inch:

  • Use latex or silicone sealant.

For gaps around ½ inch:

  • Latex or silicone sealant with a backer rod, rodent barrier cloth or galvanized metal mesh.

For gaps around 1 inch:

  • Expanding foam

For large potential chipmunk holes:

  • Welded wire screens

Whatever method you choose to seal up your chipmunk holes, you’ll need to seal the empty space completely.

If the gap is in an outdoor wall, use a waterproof option that will discourage rodents from chewing through the same area again. The solution you choose will likely be based on the size of the hole.

How Do I Get Rid of Chipmunk Holes in My Yard?

Discourage them from hanging around in the first place! Get rid of easy sources of food, cut areas of vegetation that can give them cover, and seal up any holes into your home or outbuildings

If you can make your yard somewhere chipmunks don’t want to be, they won’t want to make a home there.

No, Don’t Flood Chipmunk Holes

Unfortunately, no. Chipmunk tunnels can stretch for a long way in any direction, and they’ll likely have a number of chambers off of the main passageway to raise their young in.

It would be hard to flood out the entire tunnel due to the amount of water required (also because the ground will quickly soak up any water you do spray down there).

There are much easier ways to get rid of your chipmunk problems!

Additionally, you may ruin your in the process of leaving the hose on in there.

How To Get Rid Of Chipmunks Forever (Or At Least A While)

Chipmunk waiting under a birdfeeder for food

Permanently getting rid of chipmunks takes more than just sealing up any holes you may find, you need to approach it from several directions.

As we’ve talked about in this article, stopping them from gaining access to your home and spaces is priority number one. After that, you’ll need to discourage chipmunks from hanging around your property, otherwise you’ll find yourself sealing up holes forever.

Getting rid of your chipmunk problem will require time and lots of effort. If you have questions or doubts, it’s always best to call a pest control professional.

Seal Up Food Sources

Chipmunks love grains, nuts and seeds, so make sure that your pet food and birdseed containers are sealed and placed where chipmunks can’t get to them.

You’ll also want to keep an eye out for native vegetation in the yard that the chipmunks may be interested in eating.

Taste repellents on plants may help discourage chipmunks from making a snack of your flowers and plants.

Cut Back Hedges

The EPA recommends that you maintain vegetation free zones around your home (including trimmed back ground cover).

You even want to make sure there’s a layer of gravel or sand around your foundation to discourage further growth. And don’t just look at the ground level; chipmunks can also use climbing vines to get into attic spaces and vents.

Utilize Traps

If you can’t convince chipmunks to stay away, you may need to utilize rat or mouse traps to take care of any persistent pests.

One good idea is to make a mixture of peanut butter and oatmeal (yum) and put it on a chipmunk trap. If you do decide to place traps in your yard, you’ll want to make it hard for birds or pets to access the traps (you can use boards as a lean-to or even a cardboard box). Just make sure the chipmunk has a small hole to enter and reach the trap!

Remember to keep any animals away from the area while it’s there!

Just like any pest, the best offense is a good defense! The best way to take care of your chipmunk problem is to convince them not to take up residence nearby in the first place, by eliminating food sources and discouraging the building of burrows.

But, if you do notice a chipmunk problem, you’ve now got all the knowledge to seal up holes and stop them from damaging your house.

I hope these tips and tricks have helped you feel more confident about dealing with your chipmunk problem. And if you find you’re still having issues, don’t hesitate to call in a pro to help!

References

Glass, G. E., Johnson, J. S., Hodenbach, G. A., Disalvo, C. L., Peters, C. J., Childs, J. E., & Mills, J. N. (1997). Experimental evaluation of rodent exclusion methods to reduce hantavirus transmission to humans in rural housing. The American journal of tropical medicine and hygiene56(4), 359-364.

McLean, R. G., Ubico, S. R., & Cooksey, L. M. (1993). Experimental infection of the eastern chipmunk (Tamias striatus) with the Lyme disease spirochete (Borrelia burgdorferi). Journal of Wildlife Diseases29(4), 527-532.

Williams, D. E., & Corrigan, R. M. (1994). Chipmunks.

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