How To Stop Mice From Getting Under Your Siding

by Derrick | Last Updated: August 18, 2022

Mice are terrible “houseguests” – leaving pee and bits of poop all over the place, gnawing on all your stuff, carrying diseases into your home, and birthing tens of children. Having mice in your house is not a pretty sight, plus an infestation can start if they get into your house from under the siding. It’s crucial to keep mice out of your home , so you have to protect this vulnerable area.

Here are steps on how to stop mice from getting under your siding:

  1. Understand how mice can get under your siding.
  2. Inspect the siding and map out all the openings.
  3. Choose your sealant.
  4. Block the openings in the siding.
  5. Paint over the sealing.
  6. Use rodenticides and mice repellents .

This article will explain in detail how mice can get under your siding and how you can stop them. Keep reading to also find out how to keep mice out of your home for good!

1. Understand How Mice Can Get Under Your Siding

The first step in your “battle plan” to stop mice from getting under your siding and entering your house is to figure out how they get there. To do that, you have to understand why your siding may have spaces large enough for mice to get in.

Installation Requirement

When you install the exterior siding in your home, you need to leave some space where the siding meets the foundation. For wood siding, this space helps ensure that little bits of water can get out after rainfall, and the wood can dry properly without getting damaged.

Sidings made of metal, on the other hand, expand when the temperature rises. The space helps to give room for the metal to safely expand without getting so tight that it begins to buckle.

Pipe Spacing

As you set up your home, you’ll need to install utilities for your comfort. The pipes and vents for utilities like furnaces, water, heating, or cooling will often need to pass through the siding. For the pipes to pass through conveniently, the holes drilled in the siding have to be larger than the pipes/vents. 

Because of this allowance, there’s usually a tiny extra space left after the pipe is inserted. In some cases, these holes are large enough for mice to get in right away. Cracks can also form over time to widen the spaces, letting in the mice.

Mice are extremely well-equipped to take advantage of all these spaces, no matter how tiny they are. These animals are excellent climbers and can jump as high as a little over one foot, so the short trip up the foundation of your house won’t deter them.

They also have flexible rib cages that they usually collapse to make their bodies small enough to squeeze through super tiny spaces. If a mouse’s head can get through a hole, the rest of the body is usually a breeze. 

Because of these capabilities, mice can fit through cracks as small as a quarter-inch. A common rule of thumb to figure out if a mouse can get through a hole is to put a pencil through it. If a pencil can fit through, mice can!

2. Inspect the Siding and Map Out All the Openings

Now that you know what to look out for, you should start to inspect your siding as soon as possible. This is gritty work, but it’s a super important part of stopping the mice in their tracks because it helps you determine which openings need to be blocked. 

To inspect your siding, wear house-chore clothes that you won’t mind dirtying, and bring these tools with you:

  • A bright flashlight
  • A small inspection mirror
  • Latex gloves
  • A pencil
  • A marker
  • Eye protection gear
  • Arm protection gear

You need to wear gloves, get on your knees and slowly crawl all around the outside of your house while running your fingers through the siding. The part of the siding where mice are most likely to find a way in is the area behind the bottom row and just above the foundation. Shine the flashlight on this part of your house and inspect it very carefully.

If you notice any hole, it might seem much smaller to you from above than it actually is. You need to use an inspection mirror like the Ullman HTC-2 Pocket Size Telescoping Inspection Mirror (available on to inspect the hole properly and figure out how big it actually is. 

To gauge the size of the hole and figure out if mice can get in, you can put the pencil through as noted earlier. If the pencil can slide through the hole, it’s a possible entry point for mice to get under your siding. 

You can also look around and sniff the hole if you can stand it. If you can spot mice droppings or perceive an ammonia-like smell (mice-pee), then it’s definitely an entry point. The gloves will help keep your hands safe from any germs that the mice pee and droppings may have attracted.

Use a marker to put a spot on every one of the holes, so you don’t miss any of them when you start blocking.

3. Choose Your Sealant

After marking out the holes in your siding, you will need to fill them up to block mice from entering your house. There are several sealants you can use for this, and they all have their pros and cons. The two sealants that are most popular for filling holes in sidings are spray foam and caulk.

Caulk Sealant

Caulk is a flexible, semi-liquid, moisture-proof sealant that can be used to permanently seal holes and cracks. There are many different types of caulk, but only a handful of them are useful for filing siding. The types of caulk used in sealing siding include: 

  • Acrylic latex caulk – This is a cheap, fast-drying DIY caulk that you can paint on. Acrylic latex caulk works for general-purpose caulking, so it can be used for wood, metal, cement-board, and vinyl sidings.
  • Polyurethane caulk – This is a heavy-duty caulk that is resistant to moisture and corrosion. It usually needs mixing before use but has excellent flexibility if used right. Polyurethane caulk is best for filling holes in metal siding.
  • Silicone caulk – This is more flexible, longer-lasting, and more expensive than latex caulk. It’s excellent for caulking damp places because it has chemicals that are mildew-resistant and can slow down discoloration. Silicone caulk is the best option for filling gaps in wood, cement, and vinyl siding.

Before choosing your type of caulk, carefully read the properties of the product you intend to buy. For filling gaps in a siding, the caulk you opt for must be resistant to mold and mildew. The product label will also have information about what materials the caulk is recommended for filling. This information can help you make the best choice regarding type and brand.

Most types of caulk come in various colors, so you want to choose a color that’s the same as your siding or as similar to it as possible. A similarity in color helps ensure the sealing isn’t obvious enough to ruin the aesthetics of the siding – especially if the hole you’re filling is in an open part. If you can’t find a similar color or shade, the next best option is to use clear caulk.

Spray Foam

Spray foam is also quite popular for filling siding holes because it’s cheap and pretty easy to use. The issue, however, is that it’s not quite as effective in keeping mice out.

If you block holes with spray foam, mice can easily gnaw or dig through the foam to reopen them. These rodents won’t just get into your house; they’ll also make a huge mess, leaving bits of foam everywhere. This feature of spray foam can be helpful if you’re trying to tell whether or not rodents are getting into your house through the siding, though. 

Some types of spray foam have repellents or bittering agents to keep mice away. However, most of these are only strong enough to keep mice from chewing through the foam, not from scratching through it. This is why spray foam alone isn’t sufficient for blocking gaps in your siding.

4. Block the Openings in the Siding

This is even more gritty work than the inspection, so you should gear up in house-chore clothes that you wouldn’t mind getting dirty or even throwing away. You’ll also need these tools:

  • Sealant
  • Caulking gun
  • Scraper
  • Gloves
  • Safety goggles
  • Cleaning rags
  • Mineral spirits
  • Siding cleaner
  • Siding zip tool (only for a large hole or tear)

Filling a Small Gap With Caulk

For a hole no wider than the width of your finger, wipe the area with a rag to get the dust, mold, and debris off. If you have some mineral spirit or siding cleaner, pour some on a rag and carefully wipe the hole with it. An alternative is to mix a bit of cleaning agent with water and use the mixture to clean. Wipe the spot again with a dry rag, then leave it to air-dry completely.

It’s usually best to clean all the holes that need filling, or at least all holes in the same area at once. This way, all the holes will have enough time to dry properly before caulking. As you leave the cleaned holes to dry, start to fill your caulk gun.

When the hole is completely dry, use the gun to slowly squeeze caulk into the hole until it fills it up. After the hole fills up, use the scraper to smoothen the surface and wipe off the excess caulk, then leave it to dry.

Filling a Large Gap With Caulk

If you’re dealing with a larger hole or long tear, a caulk filling may not do. You need to get a siding zip tool to unlock the siding at the bottom. If the piece is still usable, put some foil tape on the back, and lock it back in place. With an unusable piece of siding, you’ll have to replace it with a new part altogether.

Filling a Siding Hole With Spray Foam

Spray foam is much easier to use than caulk. Still, it’s advisable to clean out the hole like you’d do when caulking. Hold the can of foam over the hole and spray it directly. Unlike caulk, spray foam is not colored and expandable, so you can’t fill the hole with it. Leave the foam to harden over time, and cut off the excess later, if need be.

5. Paint Over the Sealing

Filling holes in your siding can leave the exterior of your house disfigured, even when you use one that’s tinted to the color of the siding. If the repairs are apparent enough to visibly affect your home, you can splash some paint over them to give an aesthetic boost.

Before deciding to paint over your sealant, you should confirm that it’s paintable. You can use any effective paint, but waterproof paint is less likely to be affected by the elements, so many people prefer it.

6. Use Rodenticides and Mice Repellents

Blocking the gaps in the siding can stop mice from getting into your home, but it may not stop them from trying. Because mice pose a health hazard and are just plain annoying, it helps to use rodenticides or repellents after filling your siding to get rid of them for good.

Rodenticides are effective, fast-acting chemicals for killing mice. These poisons can kill any rodents already in your house or those that try to get in. However, the downside is that they can also pose a health risk to adults, children, and pets.

A safer alternative to rodenticides is using natural mice repellents. Mice are averse to strong-smelling substances , so you can ward them off by placing natural repellents at their entry points. While these repellents are safe for you, they may take much longer than the harsher rodenticides to show results. Some natural mice repellents you can use are:

  • Peppermint plants or oil
  • Cayenne pepper
  • Cloves
  • Onions 
  • Mothballs
  • White vinegar (soaked in cotton balls)
  • Hot sauce


You’re all set to keep the rodents out of your house. Remember, mice are attracted by bits of food and warm, dark places of shelter. With food off your floors and clutter out of the way, they don’t stand a chance!