On Sat, 01 Jan 2011 14:48:10 -0500, Ned Simmons wrote:

T1-11 plywood? The T stands for "textured" -- similar to rough sawn
boards.

None I have seen is rough enough. The texture its self is plenty deep but a
smooth and rounded texture. The existing grooves are way too far apart to be
useful. Plus all the center baffles need to be rough on both sides.

I thought bats were pretty fussy about building materials. Is the
formaldehyde glue in plywood not a problem?

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. (De-laminates in the presence of bat urine) Plus
bat houses have no floor or bottom and unless intended for extremely cold
climates must have at least one vent. So basically formaldehyde is not a big
concern.
--
William