I want to replace an odd-sized lauan door leading to our cellar with a
used but solid wood door I got at a Habitat for Humanity store. I have
a cat who likes to go outside in warm weather, and I'm getting too old
to stay up all night with her , so I thought I'd build a "cat door."

The odd-sized original door is 1 1/4" thick, 29 3/4" wide, and
approximately 80" tall. I chose the $5.00 wooden door because its
width matches the lauan door exactly. However, it's only 1 1/8" thick,
74" tall, and has hinge placements and sizes in different areas than
the lauan.

I filled in the hinge areas with very thin panel board and can chisel
out new areas. What I'm concerned about, however, is possibly doing
all this work only to find the door out-of-level or (since it's
panelled) unable to be hung with the mullion and stiles at 45 degree
angles to the floor. The door has ancient skeleton key holes and needs
to be puttied and painted, and I don't want to waste putty or paint, or
TIME! on something that won't work.

So I just thought I'd ask if there are any tips for knowing in advance
if a particular replacement door will work in the area you need it.
Thank you.