How to Build a Bat Box

Better than Batman! Kids and parents who protect bats are the real superheroes.



Bat Boxes



“So dark of wing and king of craft, of all night flyers, the master is the bat.”

– Ms. Frizzle from the Magic School Bus


We’ve seen them careening through the air at dusk and darting back and forth erratically. We believe them to be bringers of bad luck, bloodsuckers and messengers from the devil. With their fur covered bodies and their leathery wings, bats look as if they were cobbled together by someone with a fiendish imagination and a sense of humour.

Yet bats are fascinating creatures we should respect and admire. They are the only flying mammal in the world and the common little brown bat can eat more than 900 mosquitoes in one hour. Bats use the amazing feat of echolocation to detect the exact position of their prey. Sending out pulses of sound, bats can literally see with their ears.

Bats have been struggling lately, particularly in North America. Up to 80% of bat populations have declined because of White Nose Syndrome, a fungal disease that wakes up bats during hibernation and uses up valuable fat reserves. Yes, bats are in trouble but your family can help by becoming bat protectors. By building a simple bat box on your own home, you’ll be creating some important roosting spots for bats. At the same time, you may notice there aren’t quite as many mosquitoes whizzing about your ears during those hot summer evenings.

Bats like dark and cramped spaces to roost in. Often they will creep under layers of bark, or they’ll find a nesting cavity in an old rotting tree. Your job is to mimic this space.

Bat Box

Building this simple bat box* is a great family project and should only take about three hours.


←  1⁄2″ outdoor grade plywood or 3⁄4″ pine, large enough to cut 3 pieces: 24″ x 34″; 24″ x 21 1⁄2″; 24″ x 5 1⁄2″
← handsaw or skill saw (with adult supervision)
← 1″ x 2″ pine (3/4″ x 1 1/2″ finished) large enough to cut 1 strip 19″ long and 2 strips
27 1/2″ long
← one piece 1″ x 5″ x 27″ outdoor plywood or 3⁄4″ pine (roof)
← 20 to 30, 1 1⁄2″ exterior grade screws
← variable speed drill
← one pint of water based exterior grade primer
← one pint dark exterior grade water based stain
← one tube of paintable latex caulk and a caulking gun (optional)
← tape measure

Step 1: Measure and cut plywood or pine into three pieces: a) 24″ x 34″ for the backboard, b) 24″ x 21 1⁄2″ for the front top board, c) 24″ x 5 1/2″ for the front bottom air gap board.

Step 2: Cut horizontal grooves with a saw into the backboard, spacing these about 1⁄2″ to 3⁄4″ apart. This provides anchor points for the bats to hang onto.

Step 3: Paint two coats of dark exterior grade water-based stain on all interior surfaces. The dark colour helps to absorb heat. Do not use paint as it will fill in the grooves.

Construction/photos by Matthew Bywater and Mike Schmor

Construction/photos by Matthew Bywater and Mike Schmor

Step 4: Cut the 1″ x 2″ pine board into three strips: one piece for the top, 19 1/2″ long, the other two, 27 1⁄2″ long. These will be used for the sides of the bat box.

Construction/photos by Matthew Bywater and Mike Schmor

Construction/photos by Matthew Bywater and Mike Schmor

Step 5: Use screws to attach the pine side strips, thick side down, to the back board along the outside edge, so that your bat box is 3⁄4″ wide. That is just enough space for a bat to stay snug and warm. Any larger and they’ll lose heat. Start with the 19 1/2″ piece centred at the top and continue with the other two 27 1⁄2″ pieces for the left and right sides. Caulk the outside edges and smooth with a wet finger (use latex gloves) after you have screwed down the three sideboards.

Step 6: Attach the 24″ x 21 1⁄2″ front top piece to the side strips with screws. Then leaving a 1⁄2″ gap, attach the 24″ x 5 1⁄2″ front bottom air gap board to the side strips with screws. The 1 ⁄2″ venting space between top and bottom front pieces allows fresh air to enter the bat box.

Construction/photos by Matthew Bywater and Mike Schmor

Construction/photos by Matthew Bywater and Mike Schmor

Step 7: (optional) Caulk around all outside joints to further seal the roosting chamber.

Step 8: Attach the 1″ x 5″ x 27″ board to the top for the roof. Apply three coats of stain to the exterior (use primer for first coat).

Construction/photos by Matthew Bywater and Mike Schmor

Construction/photos by Matthew Bywater and Mike Schmor

Step 9: Mount on building (south or east sides are usually best). Note: Do not mount your bat box on a tree – this allows predators more easy access! Do mount your box at least 15 feet off the ground and preferably facing south or east so the sun can warm the bat box.

Now, gather the family at dusk and try to spot these winged wonders swooping through the air, scooping up insects. and nestling in their new home.



Author: Jacob Rodenburg

Jacob Rodenburg is the executive director of Camp Kawartha and the Kawartha Outdoor Education Centre. He also teaches part time at Trent University.

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