I thought this might be worth sharing and also wanted feedback in case it isn't such a good idea as I think!
I bought a huge hutch for our rabbits the other week but despite asking around, couldn't find a suitable coating to make the floor water resistant - and if you keep buns you'll know just how much they wee!!
I didn't want the eternal problem of a damp floor that never gets to dry out especially in winter.
So. After a few days going mad thinking about this, I suddenly had an idea. I went to our discount flooring place and found a small offcut that was pretty much the same size as the floor of the hutch, but actually twice as wide - which means I have a spare piece as well. I laid the hutch floor on top of the vinyl and cut it with stanley knife, then glued it down (ok I used spray glue as it is very strong, but waited till smell had evaporated before adding rabbits!)
Then put the hutch together, I did have to make a few small cuts at the edges to accommodate the corner joints etc, but it wasn't hard - and it's amazing, we have a totally waterproof floor that is wipe clean in a few seconds. It's also acoustic vinyl (not bad for a fiver!) and therefore very thick and cushiony for them to hop about on.
I'm really chuffed about it. I also got a tray for them which I use cat pellets in - wooden ones - and this absorbs a lot of the wee, meaning it only needs emptying every couple of days (if they are in hutch, not out in run - less if out and about of course)
I don't know if it would work on every hutch but definitely does on ours.