On Oct 12, 3:31*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?

Call a local roofer or 2 and ask them if you can stop by their next
job (or 2) and grab the cut-offs/leftovers of roofing felt. They often
have short lengths that aren't worth their time to lay down.

I don't know that I'd use flashing cement...I just staple it down.

I bought open bundles of shingles at Lowes for $10 a bundle. Roofed a
8 x 10 shed for under $50 bucks!

I once built a 2 room dog house with a removable roof to make cleaning
it easier. I figured I'd shingle the roof to make it last. Damn roof
was so heavy it took two of us to remove it when we wanted to clean.

Dog never did like the house much anyway.