4" concrete for floor with slight slope to drainage area.This will make wash out a lot easier. You can get by with 5 to 6 Ft. wide runs by about 20" long so dog isn,t quite so cramped up. I normally put my houses on outside at far end of run with removable roofs so cleaning/changing bedding is easiest. You could also attach it to an existing building/garage/barn and cut access doors into building with boxes inside. Plan your runs to get some shade over them during summer months and its a lot easier on dog and if possible position bxs if outside to block out north winds during winter months. That said those dogs still need to be aired/excercised every day. Don,t just keep them stuck in those runs as they,ll get zero exercise. Many people get away with those little 10'x10' fenced in areas from places like tractor supply but I,m not a fan of them unless just used to put dog in temporarly. Far as materials probably easiest option is preassembled chain link fencing panels. These vary greatly in quality due to pipe size and gauge wire used. Or another option is to dig in 4x4 posts and fence in with dog kennel fencing usually available in 50 & 100 ft. rolls. Either option plan on putting at least a sloped kennel shade over run. I prefer the black mesh kennel covers with a heavy grade silver tarp over that. The silver reflects hot sun away from run and will keep it much cooler in summer. Do not use a dark colored cover over run or you,ll raise temps at ground level during hot weather. Of course a full roof is an even better option.