Roofing felt for hedgehog houses (Eskbank EH22)

I'm looking for a small amount of roofing felt, please - 3 x (45cm x 45cm) - to waterproof the bases of my hedgehog houses. After so much rain, I've realised the wooden bases won't last long without further protection.

I Freegled the roll I had a couple of years ago and rather than buying another for the small amount I need, I thought I'd try here first to see if anyone has some left over from a project. A hedgehog tried entering my house last night in the heavy rain, so any help is appreciated for what is clearly needed!