I have a 16 x 24 concrete patio in my back yard. I'm going to build a wooden deck over it, exactly the same size. However, the concrete patio is only 3" from the door footing. I can't frame the 2 x 4's standing on end I have to lay them out flat making them a 4 x 2..if you get the picture. Is this going to be a problem with structural integrity and, is laying the framing boards on their side even allowed.

Thanks.