a bit confused with your post as you mention a separate rainfly, and that 'the top part of the tent is delaminating' <img src="/forums/images/graemlins/confused.gif" alt="" /> Seems contridictory to me, in that if the nylon tent body was/is laminated that would not breath and condensation would make the tent unusable. Also since the tent's rainfly is polyester, and coated(presumably) then it is the part 'delaminating' and not the tent top. If this is the case then you must have packed it wet enough for mildew to separate the layers in the polyurethane coating from the polyester fabric of the rainfly. 'Wetting out' of the tent body's nylon material and causing it to 'seemingly leak' would be suggest to me there is no delamination of the nylon but that the rainfly is in contact with the tent body due to age or stretching over the course of years of use. If you can physically see the delamination of fabric and urethane then that is not covered under most tent warranties I am familiar with.

Re-proofing the rainfly with a product like Tectron spray once a season may help in this case. I have used Tectron successfully in the past waterproofing many items.