We built our welping box 8long x4wide with 5ft cilling, with a 12x12x4 kennal all sitting on top of a ceder slab floor. the reassion we built hte Welping box so big is to give her and the pups room to move around as the pups grow, and when the gyp wens we use the pen as a weaning pen as well. and the floor is better on the pups then the concret floor, and we built are box so tall is in case the weather conditions arnt faverbile like to cold to hot kinda weather, we can put a heat lamp in there if its cold or a fan in there if its to hot that way the pups cant get burnt or get to the elvtric cord to chew on. all the frame work is 4x4 sitin on 2x6 ceder slabs and the out side of the box is treated plywood and so is the roof and then we shingled it. works great.