I was shocked when I saw daylight the first time looking along the side wall of my slide out. I went outside and saw the the seals were there, but the floor had actually come loose from the walls and was drooping beneath the wall at the middle about a 1/2" (I could get the tips of my fingers up through it into the trailer). I contacted the dealer and talked to the service manager who, of course had never seen anything like it. He said if I wanted to bring it in they would look at it, but to be honest with me he doubted there was anything they could do. He suggested I get some of that foam that swells up when you spray it. The FLOOR is falling down. I called FR for 3 days until I finally got a knowledgeable engineer on the line who suggested I buy about 12 small steel "L" brackets packaged with four screws for each. He then suggested I jack the floor up until it was even with the wall, and fasten the brackets side to bottom, using a straight edge to make sure the floor was completely level with the wall. (I pulled up the black rubber/vinyl cover and screwed the brackets in under that so they weren't exposed.)
I ran a heavy bead of outdoor silicone adhesive before fastening them.
As I was doing this, I came across several light gauge staples that had pulled loose allowing the floor to drop down. I went back to HD and bought more brackets and fastened them all the way around. Then I ran another heavy bead of silicone under the rubber/vinyl edge that drops down and staked up a horizontal 2x4 all the way around until the adhesive set. Now I feel no draft and can see no light. It really bothers me that assemblers tacked that floor in with a staple gun. But the service manager at the dealership where I bought it new just assured himself that he will never get another dime from me.
Moved from a 2,000 SF home into a 2014 Puma, about 260 SF. On two acres. We brought in power, water, and installed septic system. We've been here a year now, my wife, myself, and an 80lb female Weim named Daisy. We can barely see our nearest neighbor, one of two.