Need a cover for our attached spa (below). It's nominally 6x9. Not interested in spending several hundred dollars (or more) for a custom made cover, at least not at this time.
The intent of the cover is strictly to keep the spa clean of debris, not concerned with insulating properties. My idea was to cut some plywood to fit and stain it to match the nearby cedar pavilion/deck. My wife nixed that idea - "too heavy". So maybe we can use some kind of sheet foam but obviously needs to be thick enough to have some rigidity. I believe I have read that it needs to be covered with vinyl or something to keep it from breaking down from exposure to the elements and the humidity from the pool water.
No idea where to obtain the necessary sheet foam and how to cover it.