The above are two good, and siilar in approach answers, but there are two issues it seems no one includes:
1) If you house was built before 1978 it must be inspected by a certified contractor or lead ... read more
ConsultĀ a professional.
Whether it's 12" or 12' off the ground there are too many safety and code issues for the average homeowner to tackle. Better to do it right than to regret it later.