Travel trailer underbelly

I think camp-n-family and opnspaces have the correct answer. My Forest River Vibe is made in the same factory as your Windjammer. I have bulges in the coroplast where items protrude below the frame. I've had parts of mine down several times, first time because the fresh water tank was improperly secured. You can remove the screws in the area of concern and inspect your situation and only spend 30 minutes to do that. You'll find how simple that is to do and learn a bit about your trailer components. I have used expanding foam spray to seal where the coroplast edges gap. If already sealed with foam, just use a serrated kitchen knife to cut the foam. There is a plastic liner above the frame under the flooring but that seems impossible to be hanging considering the coroplast. However, it has been 15 months since I visited the factory and they may have changed construction methods since mine was built.