Bat House Forum

[BatMan]

I'm contemplating building a giant rocket box, either modifying the 2 chambered cedar bat house builders hand book design I currently have up or starting new. This time I plan on using a 4x4 post instead of the 2'' metal pipe, like you have done with all your rocket boxes Joe. I'm thinking if I go with a 4x4 wooden post I can notch the post for additional roosting space.

My only concern is having enough width on the wood on the outer chambers, I think the widest the wood comes is 12'' which is of coarse a nominal size. Has anyone ever joined together 2 pieces of wood for a bat house ? I'm wondering how long the joint would last in the elements. Is this a feasible idea, please give me your opinions on this.

[Terry Lobdell]

Batman, I built a fairly large double creviced rocket box last year. I used one inch boards horizontally with different widths. It fit over a 6"x10" post. The different widths allows you to stagger sections of your baffles and then you can screw them together.......kind of hard to explain here..........The first baffle or shell was 8"x12" and fit over the post like a sleeve.........I used pet mesh stapled to the wood for the bats.  Allowing for a 3/4" crevice all the way around, I made the second baffle/shell  11 &1/2" by 15 &1/2" again stapling pet mesh to it. The outer shell was 16"x20" again allowing for a 3/4" crevice.

I used pieces of plastic cpvc  1/2"pipe cut to 3/4" lengths as spacers for the crevices.

[Gran]

one thing to keep in mind.  This one will get heavy in a hurry as you add chambers.  make sure you can mount it

[Terry Lobdell]

I made mine in individual layers........each layer slips over the previous one.....

I think if I would have added a 3rd crevice, the outer shell would have had to be in 2 pieces to be light enough for me to carry it up the ladder by myself...........

But that's probably the best way to build any large bat house............make it in easy to assemble and disassemble componants for ease of mounting and possible design changes in the future.

[Joe Spencer]

Ya I agree with Terry Batman.  Just turn them horizontally to obtain the width you desire. This outside piece of the rocket below is identical to the one you see on the BHF current homepage photo which I built 2-3 years ago. I'll hopefully soon be placing two of these bat houses in an environmental area in my town (pending approval):

Photo below.  12" wide rough pine boards.  All 4 ripped on my table saw at 12" which when arranged and fastened as you see below provides a perfect square.  The same procedure is used for the next two inner sections as well.   The two inner sections (not seen but seen on current homepage photo are fastened together and are light enough and easy enough for me to place on top of the post. There is a stop inside the smallest piece leaving a large heat retention cavity to be filled with sand/water weasels or whatever you desire for heat retention.  After I mount and fill the cavity I then slide the 12" section (seen below in photo) over the top of the mid section which has 3/4" spacers on it.  The 12" section has a square roof top.  I just confirm squareness and accuracy of the section by measuring diagonally with a tape measure.  If opposite corners are within a 16th", its good enough square for me and likely the bats too!  LOL.  I too have found the largest standard pieces are often limited to 12" widths at most saw mills.  If I'm inclined to expand and make it wider in the future, I'll just add another stackable gravity chamber as Terry has mentioned.  It will of course exceed 12 inches so I'll just turn the lumber horizonally and join 2 horizontal pieces with 45 degree strips of wood the largest outside section similar to what you guys have mentioned above.  As I make more of these in the future I'm going to consider creating holes in the top of sections and then in the gable ends of the roofs allowing air to rise out to just to experiment with Kent's theory of air movement at the top.  Indeed the bat house would lose warmth throughout the night by doing the latter however, maybe the heat retention area should help with that a little.  After looking at bats in attics up at the top peak they seem quite content there in a few barns in my town and as Kent mentioned there is a considerable flow of air up at the top which is in addition to the warmth.  Always experimenting to see if there is a preference by bats.  Terry, interesting on the spacers... What did you use to fasten them? I like the idea of using round impervious stuff which the guano would not accumulate excessively on.  Currently at the chamber roof I use four solid 3/4" strips spacers of wood on the top to prevent twisting and then use four small separate spacers angled severely on top of the spacers to inhibit guano accumulation.


Image shack lost photo sorry


No this is not the Ten Commandments retrieved from the ARC (below).  Just my bat grippable foothold kerfs inside the rocket chambers.

image shack Lost photo
Great stuff and I'm looking forward to your future insight!

[Terry Lobdell]

Joe, I just used a drywall screw coated with caulking and just screwed it from one baffle into the inner one passing through the plastic pipe. I coated the screw with caulking to protect it from possible corrosion from urine.

I've also thought about using rubber or some type of foam spacer that gives a little when you slide one layer down over the other.

On the house where I used the plastic spacers I only had them on the bottom. To align the top for the correct spacing I just used a stick as a feeler guage and then screwed down through the top. I had a ceiling also of 1" boards in all layers which adds to the insulation value.

Thanks for getting this forum back up Joe!

[Joe Spencer]

Terry that's a great idea.  I'm going to finish these rockets with the cpvc spacers and really appreciate the suggestion.  I think I'll make a wooden mitrebox with a stop on the end to produce accurate 3/4" length spacers and cut 3 or for 4 simultaneously using a panel hacksaw (below) to cut the cpvc unless you or anyone has a better suggestion.  I have a fine tooth blade on my Dewault miterbox saw but I found the blade dulls quickly when I cut Cpvc.  Offbeat a little - there have also been bat houses made out of screening and CPVC (pet mesh would be great)  where one places cpvc side to side through bat house sides and then weaves the mesh around them creating porous mesh chambers.  You would have to add attic sand or equivalent to satisfy thermal mass loss though in this design. In time the mesh would expand and it would become loose but maybe you could create a hanging gravity weight to keep it taught.  I may experiment with the latter soon.  Fantastic and thanks again.....

[Terry Lobdell]

Joe, that's exactly how I cut mine.......although a tubing cutter would work also........like the kind used to cut copper pipe........

[BatMan]

Those are some good ideas, thanks. I think I may go with the pvc idea as well. I may use 1/2'' pvc and cut them 3/4'' for the spacing using some pvc cutters. Gran you are absolutely correct, I learned my lesson with the last nursery I made that was way to heavy and ended up falling on us while we were putting it up.

[BatMan]

I have another question:

Since I'm going to assemble this in sections, I'm thinking about using concrete in the "core" as a heat sink. Would it be a good idea to extend the inner section up into the attic so the concrete will be exposed to the attic temps ? Or would this diminish the heat sink effect ? In other words, should there be a wood buffer between the changing temps of the attic and the concrete core ?

[Terry Lobdell]

Batman, What might work well for both a solid pole and space for your heat sink material might be a pole of 4 - 2X6's with a hollow center. You could use treated lumber for the section in the ground then use regular lumber the rest of the way up. I've made 2 poles this way assembling them on the ground first in 2 or 3 pieces carefully staggering the splices.

Putting it together in 2 or 3 pieces makes it easy to put your pole up. I just set the base section in the ground and back fill it firmly.

Then, I lean a ladder up against it and am easily able climb up a few steps and splice the 2nd section in place.

I should add that I also make sure the 2 pieces fit together correctly on the ground first.

You can place your heat sink in the top hollow section of the pole. I used bricks in one and a bag of pea gravel in another......

I have found these poles to be very rigid for their size and easy to put in place.

[Joe Spencer]

Since heat always seeks cold, instead of extending the concrete into the roof for heat retention,  why not just add some sand to the roof attic cavity and have the roof as a separate section.  The roof cavity could be filled or drained easily enough on site and make the roof only heavy enough to mount safely.  What about using a similar approach using Terry's hollow post with it being completely hollow and then filling it with pea stone from the top.  Have a small cut-out 1-2 feet up from the post bottom to drain the pea stone if needed in the future.  If your worried about the post being compromised strengthwise, just use poly glue.  I have tested it after drying for two days and then submerged the two glued pieces in a bucket of water using a weight and I could not get it apart.  When I finally succeeded it actually split apart with the poly joint remaining intact.  Poly glue (gorilla glue etc.) really holds up well unlike water based glue.  Warmth from the stone post interior should rise for many hours into the bat house well after sundown.  Again since heat seeks cold through conduction and the wood is less conductive, once the pea stone heats up throughout the day inside the post, it should be slowly released throughout the night within the wood wall with the latter being an insulating factor.  Of course utilizing such a heavy post setup would necessitate using the suggestions herein to reinforce the post stability wise. 

[BatMan]

Well here are some pics of the recent build. Sorry, the new pics are behind the old one's, I don't know why the site put's the newest pics last. The attic as you'll see has vents on the "gable ends" and the two outside chambers have small 1/4'' holes all the way around, so I'm hoping to get some air flow in the 2 outside chambers.

I'm thinking before I put it up I'll put some plywood on the outside to cover up the joints made by piecing together the 1x's.

 

http://home.comcast.net/~mh701/wsb/html/view.cgi-photos.html-.html

[Joe Spencer]

Fantastic! I like the quality pics and bat house you have built.  That is one massive mega rocket.  Looking forward to your potential occupancy.  Are you placing it in your own yard or is it destined for an area with more water nearby? Nice going!

[Terry Lobdell]

Very nice Batman! How thick are your plywood baffles?