We have the Carefree Add a Room, to answer your question the skirt attaches with twist lock fasteners about every two feet or so to the side of the trailer at the bottom lip. It does not "seal", just attaches. You can either buy a camping mat from carefree or others, use nothing or buy a tarp, its up to you. Whatever you use does not attach and seal but will only be staked to the ground. We love ours and it sure is nice to have additional space, it keeps the bugs out and is nice when the weather is bad. Be sure to buy the delux model, its a little more $ but well worth it. Heres where we bouht our Funfinder and screen room, ask for Ted in parts.
, 231 739 5269