A squirrel house (nest box) is a simple wooden box about 10–12 inches square and 18–24 inches tall, with a 3-inch entrance hole near the top on one side, a few drainage holes, and an untreated wood interior. Mount it 15–20 feet up on a sturdy tree trunk, away from your house, and it can give squirrels a dry place to nest—often keeping them out of your attic.
Why Put Up a Squirrel House?
- Provides shelter where natural tree cavities are scarce
- Gives squirrels an alternative to attics and soffits
- Lets you watch wildlife in your yard
- Popular with gray, fox, and flying squirrels
Recommended Squirrel House Size
| Feature | Gray / fox squirrels | Flying squirrels |
|---|---|---|
| Floor (inside) | About 10 × 10 to 12 × 12 in | About 6 × 6 in |
| Height | 18–24 in | 12–14 in |
| Entrance hole | About 3 in, near the top, on the side | About 1½ in |
| Mounting height | 15–20 ft | 10–20 ft |
Placing the hole on the side, close to the trunk, helps protect the nest from wind, rain, and predators.
Materials
- Untreated cedar, pine, or exterior plywood (¾ inch)—never pressure-treated wood inside
- Galvanized or exterior screws
- Hinges or a screw-on lid for cleaning
- Drill, 3-inch hole saw, and saw
- Galvanized lag screws or straps for mounting
How to Build a Squirrel House
- Cut the pieces: two sides, front, back (extended at the top and bottom for mounting), floor, and a slightly oversized sloped roof.
- Drill the entrance: a 3-inch hole on one side panel, a few inches below the top.
- Roughen the inside or add a few horizontal saw grooves below the entrance so squirrels can climb out.
- Assemble the sides, front, and back with screws, then fit the floor recessed slightly and drill 3–4 drainage holes in it.
- Add ventilation: leave small gaps under the roof edge.
- Attach the roof with a hinge or screws so you can open it for cleaning.
- Optional: add a handful of dry leaves or wood shavings inside (no cotton or fabric).
Where and When to Mount It
- Mount on a large, healthy tree trunk 15–20 feet up.
- Face the entrance away from prevailing winds.
- Place it at least 20–30 feet from your house so squirrels don’t move to your roof.
- Put it up in late summer or fall; squirrels raise litters in late winter–spring and again in summer.
- Use lag screws or straps loosely enough to allow tree growth, and check yearly.
Build vs Buy
Pros
- DIY lets you choose thicker, untreated wood
- Cheaper with leftover lumber
- Easy weekend project
Cons
- Needs a saw and hole saw
- Store-bought boxes are quicker
- Cheap kits may use thin wood that warps
Maintenance
Clean out old nesting material once a year in late summer, after young squirrels have left. Wear gloves, and check for wasps before opening. Check local wildlife rules if you plan to relocate or disturb nests.
Frequently Asked Questions
Do squirrels actually use squirrel houses?
Yes, especially where large trees with natural cavities are scarce. It may take a season before squirrels move in.
How high should a squirrel house be?
About 15–20 feet off the ground on a sturdy tree trunk for gray and fox squirrels.
What size hole for a squirrel house?
About 3 inches for gray and fox squirrels and about 1½ inches for flying squirrels.
Will a squirrel house keep squirrels out of my attic?
It can help by offering an alternative, but you still need to seal attic gaps and vents.
What wood is best for a squirrel house?
Untreated cedar or pine, at least ¾ inch thick for insulation. Avoid pressure-treated wood.
