I have a two story porch with rotting deck boards and corner posts on and under the first floor deck. The supporting columns are wrought iron and are in good shape. The roof is a continuation of the two family structures roof and is covered with slate. Problem is the columns are through the first floor decking at this point and corner posts are not very sound either. How can I safely jack up this porch in order to replace the first floor decking and most of the structural members. (joist, corner posts, sill plate). Under the current support system is a concrete footing that is in good condition.
PRK, sounds like a job that you should hire a contractor for. While I am all for DIY repairs and home improvements, this could turn into a very bad situation quickly. If not supported properly, you could cause the second floor deck to lower. If jack up to high, could jeopardize the 2nd floor deck as well as the roof above it.