I have just completed 2 rocket bat houses and have incorporated sand into plastic bags, into the centre portion where the 4X4 post goes into, I divided this compartment in half. The mtg. post goes half way up into the rocket house and the top half is filled with sand bags. I also inserted bags of sand into the roof cavity. I am hoping that this will act as a heat sink and keep the house warmer for a longer time, giving off heat slowly. the rest of the house is made of 3/4 inch sheathing grade ply wood. It is painted 3 coats of water base black paint. can't wait to try it out! I used Stainless steel screws and wood glue on the outside to fasten the sides together.
WEE WALLY :D :brightidea:

