Making a raised floor for an avairy

I'm hoping FatherJack will see this as he may have the solution

I have an avairy measuring 3ft wide and 8 ft long which I need to put a floor into. The avairy is down the side of the house and a puddle always appears when raining next to it. The avairy at present is just sat on some small stones/gravel on top of concrete. I cannot remove the gravel as our house is rented. I'm thinking breezeblocks with some sort of wooden floor as a base with lino on the top? It needs to be cheap else I can't do it and I need to sort this soon as we have a new furbaby family member to go in there (i will introduce her shortly)
Thank you!

Hudad is at work but Humum is home with a poorly back. She says can you get hold of any free pallets? (Try touring the industrial estates and fluttering your eyelashes - there are always loads going spare at her work.)

You can get ones where the tops are fully boarded with no gaps between the boards, and these would be best as you could just put a thin layer of ply on top then lino. But even the type with gaps between would do, you would just need to use something sturdier under the lino. Depending on the pallets, you might need to cut them to size and mess about a bit to level them up, but it's effectively free, cheap decking

The only expense would be a sheet of ply and the lino. Although if you had something suitable to paint the ply with, you might get away with just doing that and not bothering with the lino.

We had the corner hutch mounted on a pallet as it was in the soggy corner of the patio, also the chalet was completely built off a pallet base - pallets are great

Be warned that a lot of buns will be able to squeeze under even quite low pallets and hide, even the ones you think 'nah, a bun could never possibly fit under there' so it can be worth blocking off the gaps round the edges too

I could look for pallets, I hadn't thought of that even though the rexes run is mounted on pallets duh! My sisters hubby works for Wickes so he may be able to get some for me or if not the wood recycling project usually has an assortment to choose from. Thanks Sparky Hope you humum's back is better soon, sore backs are awful.xx

About small gaps, my rexes have built an undergound system under their run, the pallets are sat half on concrete and half on soil. Luckily they come back to me when I call them else I'd have to excavate their run every time they free ranged the garden

Yes the easiest way is to find pallets and then put sheets of exterior plywood on the top, or even decking on the top of the pallets