A couple of years ago, I replaced a sliding glass door with french doors. I hired a contractor who I respect and did a good job I believe. He pulled out the sliding glass doors and plugged in the french doors (I'm simplifying it, of course) making no additional changes other than to the area immediately around the door. We are now in the process of selling our home. When the inspector came out for our potential buyers, he put an ambigious note on the report of "wall shakes when back french doors are closed". This led to the buyers wanting to send a contractor to look at the wall (understandably they were concerned) because I said I was not going to pay for the wall to be fixed or even looked at. The contractor came out, opened and shut the door several times, moved his stud finder around a little, and then asked me what the issue was. I told him all I knew was what was in the report, that the inspector stated the wall shakes. He did more of what he did previously, again asked what the deal was, and then left when it was clear he couldn't find any issue. He came back a little later when I was not home. My agent was there as we agreed that the buyers could look at the home that day. This was after speaking with the buyer's agent. The second time, he said he found a problem. He said he couldn't find any studs supporting the door, and that because we switched door types, the wall doesn't support the to and fro motion of the door since it was built to support a side to side motion of the sliding glass door. I think he is full of it. I can find the header above the door frame, approximately 10-12 inches. I know enough to know that this is the board (3 x 8? or something) that runs from side to side a full foot above the frame. Additionally, I am able to find the studs that run from the header up to the ceiling, spaced 16 inches apart across the entire header and width of the door frame. The outside of the frame appears to be appropriate as well (not sure of the terminology, but the cripples? etc) I'm certainly not an expert, but believe a couple of things and was hoping someone with knowledge would correct me if I am wrong. First, door frames are built to code, not to fit specific door types. For example, you would not build a door frame into a wall, header, etc one way for a sliding glass door vs a french door. Second, if a door frame that is downstairs on a two story home were built incorrectly originally by the home builder (as he is saying out of one side of his mouth) it would show it after 9 years since slamming of a door doesn't come close to comparing to the thousands of pounds of weight on a load bearing wall so door type wouldn't mean anything. Third, when replacing a sliding glass door with a french door, you do not have to break into the wall/frame and reinforce them. (This is what he is saying out of the other side of his mouth). I greatly appreciate any insight!!!