Nana-nana-nana-nana Bat Box! This project provides a much needed home for the commonly misunderstood and under-appreciated flying mammals. Why would I want to harbor these flying rodents on or near my property?

Bats are very efficient hunters; most consume up to 50% of their body weight in insects each night. Little Brown Bats, the most common bat in Canada, can catch hundreds of mosquitoes in just one hour. Many insects have developed the ability to hear bats even at great distances, so that the mere presence of bats in an area will vanquish insect pests (source: ofnc)
Bats are endangered, the first reported cases of White Nose Syndrome was in 2005 in the US (CBC news story). Since then the fungus has spread over eastern Canada and has decimated many colonies.

I am also interested in reclaiming discarded material to transform them into useful objects. This is my first attempt at harvesting a pallet, it was actually more challenging than I expected. It was also a great project to get my kids involved with, and they learnt something about conservation sustainability and woodworking.

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Step 1: Required Items

This project requires a pallet: almost all businesses have some "around the back". Make sure to ask before taking them, they are often recovered by the supplier or sold by the store. Make sure the pallets are heat treated (HT) rather than chemically treated to ensure the bats don't get intoxicated.

You will also need some woodworking tools and other various hardware:

Hammer
Pry bar (or Pallet Breaker)
Drill with a few bits
Various screws and or nails
Paint-able caulking
Very dark water based wood stain
Water based varnish (or dark paint)
A few shingles and a stapler

Step 2: Harvest the Pallet

Dismantling the pallet was more challenging expected. Not all pallets are created equal; and the one I found was for paving stone and was very heavy and built to last. I was able to take it all apart and remove the nails in just over an hour, and I ruined one plank. I ended up cutting most of the ends off the planks as they were quite damaged from my prying.

You can more efficiently break pallets down if you have a pallet breaker. You can make one yourself.

Just take your time and pick your spots for prying, you can often tell where the plank will break before you start. I am quite certain there are some more experienced Pallet Harvesters out there. Feel free to comment and I will update this section with your tips.

Please be careful of the nails, it is easy to forget that you have a bunch of planks with rusty nails lying around for your kids to jump on, or yourself. Also, safety glasses are always recommended.

Step 3: Plan Out Your Box

I wrongly assumed that I was going to have excess planks: I ended up using every last piece... As mentioned earlier, this was a pallet for pavement stone and so it was very heavy duty: the wood thickness is total overkill for this project.

Your plan will likely differ from this one. I researched Bat Box design quite extensively before starting, and there are many different designs and plans available out there. There is also this instructable by crudworks and this one from slylee.

Your location should affect your design. Most boxes recommended for Canada appeared to have a narrower gap (3/4 inch) to host the Little Brown Bat, and were less concerned with ventilation (it gets cold here).

Don't forget to leave some plank sticking out the bottom for the bats to land onto. I had two chambers so I had a couple levels of landing strip.

Cut your planks to length; my box was 20 inches by 24 inches, with the center planks at 19 and 1/4 inches. See the details on the image.

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Step 4: Get Your Groove On

Bats have quite strong claws and feet, but they still need some roughness to cling to. Secure the plank into a clamp or vise and make a score every 1/2 inch or so. I used a circular saw with the blade adjusted to about 1/8th of an inch. The planks are quite uneven so I had to adjust the blade slightly lower for warps in the wood. I scored all the parts that were interior surfaces; the center planks were scored on both sides.

Step 5: Assembly

I would have used deck screws for this project, except that I only had a handful of them, and I had buckets full of galvanized nails. The pallet wood I reclaimed was quite hard and the planks were prone to cracking so I predrilled most of my nail holes (with a small diameter bit). This made it a lot easier for my helpers to slam those nails down.

After much consideration about potential issues, I assembled in the following order:

Clamp down the center planks (grooved on both sides) and nail down the side piece (centered). Leave a 1/4 inch gap at the top so share heat across the center barrier.
Turn it around and nail the other side piece; check that the angled roof cuts are on the same end.
Nail the roof onto the top; make sure that it is flush with the back planks (not installed yet).
Nail the front and back planks.

Step 6: Finishing

Caulk the cracks and holes; if you live in a warmer climate, you may decide to leave these open for added ventilation. Wait till the caulking is dry before painting or staining the exterior of the box. For cold climates, it is recommended to use a very dark color to absorb sunlight. This is another step that is kid friendly, I totally let them at it, and they did a great job. Make sure your paint or stain is water based, this was mentioned in almost all the instructions I found. In my case the stain does not offer any protection for the wood, so I had to varnish the box after I had the two coats of stain complete.

I had some tar paper left over from another project that I used to protect the roof and provide a little extra protection from the rain and snow. I stapled the piece into place, then I cut off the excess.

Step 7: Installation

A few guidelines I found online about installation include:

Near a known bat nesting areas (hibernacula).
At least 20 feet off the ground (or in my case, as high as my ladder could take me).
Within 400 meters from an open water source
A wide area around the box that is unobstructed
In northern climates the box should get as much sunshine as possible (south facing and not shady)

I considered installing the box onto the side of my house, this would provide a little extra heat for the little guys, but I didn't have a spot that fit the criteria. I used the biggest screws I had on hand and pre-drilled them into the support to make quick work at the top of the ladder.

My girls enjoyed the project learnt about sustainability, habitat protection, and the final result is quite appealing. I won't know if I will attract any bats till later in the summer, I can update this instructable as the situation evolves.

I am not an expert so if I have made any errors or you see any potential improvements, please leave a comment.