9. Occasionally an optimum site can be found on a structure. This type of mounting might be desired when evicting bats from the structure, or when post mounting in a yard is not an option. It is usually not necessary to mount the box on the structure to ensure a successful eviction. Here a rope holds the box while bolts are installed into prepared masonry anchors. South facing chimneys should not be overlooked as possible bat house locations especially when working with small lots.
8. If desired, supports are installed while the concrete hardens. Supports can be removed after 2-3 days. Supports are usually only necessary if an extra large diameter hole was excavated or high wind is forecast.
7. The post is centered in the hole using the digging bar if necessary. The post is then twisted so that the front of the box is facing about 135°, or about southeast. The post is leveled but allowed to list backward slightly at a point where the post is best balanced.
Add concrete following directions on the bag. Concrete can be mixed in the hole as well. Pour 1/3 of the cement mix on all sides of the post then add a small amount of water. Mix with the digging bar and repeat until the hole is filled. If the hole is too large and concrete mix is low, add rocks intermittently to the mix.
6. The box can be raised by two or three people while one additional person guides or kicks the bottom of the post into the hole. The box will be very top heavy and the "guide person" must prevent the box from toppling backwards during the lifting. The box also can be lifted by two people with the aid of a rope attached 2/3 up the post.
5. The box should be reinspected for any seam which seems separated or unsealed. Often an additional bead of sealant is applied over each roof seam to ensure a quality seal.
Encase the entire upper mounting lip in caulking to protect the top edge of the box and mounting screws.
4. The box is attached to the brackets using about nine screws. Five in the upper mounting lip as shown here, and four or five through the screened landing plate. Three Chamber bat houses only need 7-8 screws total.
3. Center the lower pole mount bracket on the post. The bottom of the lower pole mount should be about 34 inches from the top of the upper bracket. This will insure that the bracket is covered by the bat house. Affix with two lag bolts one at a time, again pre-drilling them. Check the bracket against a square to make sure it is perpendicular to the post before drilling the second bolt.
If desired, the brackets and entire post can be painted with a quality exterior stain or paint.
2. Place the top pole mount on the post and pre-drill holes to make installing lag bolts easier. Two bolts in the front, and one lag bolt in the top. The front bolt holes are countersunk so the bat box will lay flat. Check the bracket against a square before drilling the second bolt.
1. A site is picked, a hole is excavated to 36'' (3 feet). Slightly more is even better. Enlarge the hole slightly to avoid leftover cement.
Do not use "quick set" spikes that just pound into the ground; your bat house WILL fall over.
Provided a good site is selected, about an hour and the following materials are needed to complete installation:
- 4''x4''x14' (for single box) or 4''x6''14' (for multiple boxes or a more permenant installation) pressure-treated post (or larger)
- pole mount kit (from BCM or a similar configuration)
- 2- 80lb. bags of premixed concrete
- 1/2 bucket water for concrete
- A bat box
- 2''x4''x? lumber to construct supports (optional)
- post hole digger
- digging bar
- cordless drill/driver (preferred)
- 5/16'' or 3/8'' wrench for pole mount lag bolts
- paint (optional-to touch up-recommended)
- small sledgehammer (for support stakes)
- tape measure
- caulking gun & roof sealant (optional but recommended)
Select the site for the bat house carefully. A poor location may never be used by bats, no matter how well designed the bat box may be. The eight hours of morning sunlight is of greatest importance when selecting a site, make sure you thoroughly understand this and other points outlined in our "Choosing the right site" section.
BCM suggests that any bat house be mounted on a post. Unconfined like a structure or tree, the relatively portable post is a flexible solution that can be placed anywhere there is enough sunlight. Avoid the temptation for the easy tree mounting, trees are too shady and few if any bats will use the bat house.
Installing a New BCM Wooden
Three Chamber Bat House on a Wooden Post