I have the full architectuals plans for a post and beam barn with a loft. I have an old uneven concrete slab to build it on. I plan on cutting into the concrete to make holes for the posts to be set into. I have no idea how I am going to get all the posts at the same height if the slab is not at the same level. I think I need to find the heightest point on the slab, measure up to the correct height, cut the post, then use a water level from that first post to get all the other posts at that same level. Any other ideas or comments are much appreciated.