Steer Planet - Show Steers and Club Calves Forum

I am cleaning out my barn and plan on building 2 pens in the corner for the 4-h Calves.  I would like to cement the stall floors but was wondering if that is a good idea?  I know for horses its bad and I would have to put rubber mats down, but what about for cows?  I can leave it dirt, but the corner of the barn I want to put it in stays wet unless I build it up some, I can put shale in it, will that work?   I will be using round pen panels that I have for the sides at first, but plan on building a wooden box stall when I can afford it.  Any suggestions? I have an old bank barn with an old fashioned shed, ventilation will come from the doors on both ends of the barn being off, I cover the ends of the shed with a tarp in the winter to protect the animals from the Pa winters.  How large should I make the stalls when I make them wooden 10ft, 12 ft.?  Thanks for any advice!!!

My pens are 10' x10' and work well for one calf.  A friend of mine has bigger pens in his barn but he usually has two calves per pen.