On Oct 12, 2:31*pm, dgk wrote:
Last year I had a 4*8 outdoor plywood board (pressure treated I think)
cut into appropriate pieces at the local Home Despot and put together
a little house for a few feral cats. I used some polyurethane stain,
caulked the seams, and figured it was pretty waterproof. Yet every
heavy rain the inside was soaked.

I figured that I'd get some of that roofing tarpaper, use the flashing
cement to attach it to the wood, and put some shingles on it. However
I can only buy the tarpaper in large rolls, which is far more than I
would ever need.

So, what's a good way to waterproof a pet house?

Is the roof sloped? I'm wondering why it leaks, when my doghouse,
with similar construction, does not. The doghouse roof is one piece of
painted plywood that is sloped just enough to shed water and overlaps
the walls about 2 or 3 inches all around, and the house stays dry.
Does it have a floor? Maybe the water is coming in at the bottom
somehow? All that being said, as others have said see if you can beg
a scrap of tarpaper, or just put the shingles on without it. If it's
close enough to the house, you can test it with the hose. -- H