We are building a friend some stables and we are using blocks for the outside and dividing walls. The dividing walls are about 8 courses high, so about 1.6m and then have metal mesh on top to make them about 2.4m high. This is inside a barn so the roof is pretty high. Our stable doors are 1.10m high but we have a barn set up too so only bottom doors and a high roof. I think the average stable door is about 7ft 10 inches high.