Floor for outdoor enclosure

I am going to add an outdoor enclosure connected to a sunroom for my cats. Right now there are small rocks on the ground, grass is out of the question, there is no way I could keep after it, does anyone have any suggestions as to what they would use for ground cover?

Hmm. They would claw up wood. Dirt would get muddy when it rained, sand would get hot in the sun. Concrete would be ok, with some natural area. Wood chips (no cedar) may work, but be prepared to scoop them out when they're used as a litter box.

I'd say part concrete, wood chips, and a sand box (covered from sun and rain) if you want to encourage them to pee and poop outside too. With lots of perches and some large climbable logs for scratching. Grow some flower pots of catnip and cat grass outside the enclosure and trade off pots for them to munch on. But that's just my idea.

Most people I know have grass, but some have small pebbles or wooden decking slightly raised off the ground for drainage.

An acquaintance who keeps over 100 cats in an outdoor enclosure uses a concrete floor. It's easy to clean. Another friend with over 50 cats uses wood shavings. The cats use a particular area only for their toilet so the enclosure is not only easy to clean but it does not smell bad but the cats are usually resting on several cat condos in the cattery and will not rest on the wood.

Bare wood planks or plywood covered with indoor/outdoor carpeting?

thanks for the suggestions, cat grass in pots is a great idea!!

What about 1/2 enclosure of patio blocks?

I have two outdoor enclosures. One is all concrete flooring and the other is a mix of sand/grass and patio pavers(12x12). The cats love the pavers. They retain the heat from the sun.