Bat House Forum

[Armyman04200]

Okay Another major question I had was about exterior grade plywood, many of the plans call for this and I do not know much about Plywood but if its exterior grade, isn't that treated with chemicals? Another thing, many plans say to stain the inside of the boxes with a water based stain, wouldnt this be harmful for the bats? I want to make the houses last as long as possible without harming the bats would be counter productive to harm them while helping them. My thoughts were to use the plywood for the exterior boards and use untreated boards for the partitions. To limit bat exposure to the chemical treatments I could put the fiberglass (plastic) mesh on all the treated boards, will this be okay? I am sure I will have more questions to follow, as I become more experienced I will be glad to pass my knowledge of bats and bat houses to others. Thanks guys. . .

Kyle

[William Bagwell]

Okay Another major question I had was about exterior grade plywood, many of the plans call for this and I do not know much about Plywood but if its exterior grade, isn't that treated with chemicals? Kyle

Yes and no. Exterior plywood uses phenol-formaldehyde which out gasses far less than the urea-formaldehyde typically used with interior plywood. (Interior plywood is unsuitable for other reasons since it de-laminates in the presence of bat urine) Plus bat houses have no floor or bottom and unless intended for extremely cold climates should have at least one vent. So basically formaldehyde or any thing that out gasses is not that big of deal with bat houses. Obviously pressure treated plywood is not suitable since the chemicals used to deter termites are deliberately poisonous.

William

[cloudman75]

Armyman,
If you have a source for rough sawn boards, I would suggest using those for baffles in lieu of plywood with screening. I have used both and have found the bats don't have a problem with rough boards for baffles. The screening adds to the cost and is somewhat labor intensive for me. Also I have never painted or stained the inside of my bat houses. The bats like them unpainted OK and longevity has not been a problem. I have both painted and unpainted exteriors.
I use a water based latex for that. I have built only 5 houses and purchased one ready made. All have done well using a variation of the PA plans and Fla. Plans I posted for you. Terry Lobdell has built many bat houses so maybe he will give you some pointers.
Also I used Terry's idea to build a T post of 1x4 treated which is somewhere around 20 ft long. I can't remember the exact length. I posted it on the forum.
It has supported three bat houses no twist or warp through last winter and this summer. You could build one for about the same price of a 20 ft solid 4x4 using screws. Take a look at Terry's post and mine from 2010 if interested. Here is the link to my post on a hollow pole I made in 2010.

bat-houses-hollow-pole-t956.html

Frank

[Terry Lobdell]

Armyman, I don't use plywood at all any more for bat houses.......besides the outgassing issue is the fact that plywood warps too much........

I don't think you can beat rough sawn boards for baffles......the bats have no problem clinging to them and it saves a lot of labor........

I have stained the entrances of many of my bat boxes with a watered down latex stain........simply to darken the interiors........I'm not sure if it is neccessary.......my bats use both boxes with darkened entrances and those with undarkened entrances........

Hope this helps!

[Emersombiguns]

Mine are not stained on inside, and painted black on outside. Exterior grade. I solved the baffle warp problem by using some small boards to hold the baffles in place while I used a 4" long small drywall screw to go from the outside(front) all the way thru 5 boards into the back board. You don't go thru the inserted boards they are just there in the center to keep distance between baffle boards on the inside constant 1/2"..I used 2 of the drywall screws one halfway down from the top and one near bottom edge. Both are in the center of the 24" wide house. Then you just "slide" the spacer boards out the bottom-and the spacing is set now as the dry wall screw hold them apart. This has fixed my newer house. So far is great and this house is full of bats.
I would recommend cutting some roll shingle roofing or a spare shingle and making a shingle roof for your house with a slope. My houses were holding water on top and starting to dry rot the wood even though I painted it with tar type roofing paint. Do it NOW while nothing is in them, and it can dry out for months during winter. My houses faired so well last 9 months I doubt I will put them down this winter. Also, I am a believer in tilt over metal poles. Go to local fence place. I can get them up to 22' long here-reasonable. Randy Haughton,La

[IowaNate]

I have had great success using standard 1x12 pine boards for fronts, backs, and partitions, 1x6 for sides, and 1x8 for roofs. I just scratch all interior partitions with screws horizontally. Now 11.25" of width might not seem like alot for today's "standards" of bat houses, but I don't have to worry about warping or any off-gasing. Here is a link to my post showing this smaller design. Best thing about this design is it's low cost, ease of construction (even with just a manual handsaw and small battery drill) and the ability to make the house as tall as you desire. smaller-bat-house-t564.html

[Joe Spencer]

When I do use plywood I use natural decay resistant douglas fir and only use it for the back only. I use 1" rough pine for interior partitions/baffles and sides. Lately I have been using rough pine for the entire house especially since plywood became so expensive.