I recently moved and have the chance to build an outdoor pen for my G/F's sulcata.

He's about 20lbs and has been kept indoors, since he was 2days old
He likes his hide/hut and LOVES belly heat.

I know the belly heat isn't needed. However it helped keep his enclosure temps up, in the winter. Turns out he loves the belly heat. He will chow down in the am and then go lay out on the "hot spot".

Back on track... Tortoise pen ....
FWIW Im in Arizona E. Valley (Phx/Metro)
Dirt floor/concrete floor ? Sod? (if that's an option)
Square footage ?
hut/hide - above ground or partially buried ?
Good sulcata proof water/food dishes?
Walls - Cinder block? Wood? Other?
Walls - on ground or slightly buried? He has never been able to dig in the past. So I don't know if this will be an issue.

Any other considerations/ideas/suggestions?

Thanks in advance.