According to Max Brook's book, The Zombie Survival Guide, zombies have little to no hand eye coordination. Only one out of four zombies can even climb a ladder. This being said, stilted houses near flood areas are the safest house to live in during a zombie attack. If you are attempting to build a completely zombie proof house, get rope ladders. In case of attack or a class 3 or 4 outbreak, this type of ladder can be rolled up to prevent zombies from possibly climbing up it. You can also climb down to escape if nessecary. Last but not least, if there are thieves or looters in the area, they can't take advantage of a ladder that's out of their reach, compared to one on the ground. also NEVER go in a cave to hide