Expert: Dan Griffin - 2/19/2009

Question
I wish to transform an existing carport which has dirt floor into a living room. I would like to know how I can make a timber floor foundation on concrete stumps whilst retaining existing structure, that is without having to cut existing posts. The carport is attached to the house and there are four posts on the opposite side, one on each corner and two in between about 2.3m apart. Do the new concrete stumps for the foundation have to be in the corners under existing posts?


Answer
Monique,  if this will be inspected by code enforcement, there will need to be a continuous footing installed aroung the perimeter of occupied living space.  This footing will need to be deep enough to comply with your local frost depth requirements.  I assume the carport structure must be exceptional if you want to keep it.  A carport usually doesn't have enough head clearance and the roof structure must work with the roof of the house.   A footing can be designed to enclose the columns and bearing pads.  I assume you intend to have a stem wall and crawl space with a wood framed floor system that matches your existing floor level in the house.  This will probably require some excavation to get sufficient clearance.  The footing will require concrete work, the stem wall can be either concrete or cement block.  The elevations will be determined by the existing finish floor height and the lumber requirements to meet span and load conditons.  It sounds like you need to consult a good builder in your area that can see the circumstances and offer some choices.