Vertical storage of Kayak

I have extremely limited storage space and no kayak as of yet. I am actively shopping but my major concern is storage. The only place I have to store the boat would be in a rental storage area which is tall enough but only about 6 foot square on floor space. It seems to me that leaning the kayak against the wall would be the only way I could store, but then I worry about such issues as warping and buckling. Any words of wisdom?

Check out the
Kayak Storage…AGAIN thread to see what Dagger says about storing their plastic boats. They seem to prefer on end storage to anything else.