What do about sticky tent material?

I have a Sierra Designs tent that is about fifteen years old. The inside surfaces of both the floor and fly have become sticky. I stored the tent in a closet on the upper shelf the entire time where it is very warm much of the time, so I guess the stickiness is from the water repellent finish breaking down. If the finish breaking down is the cause of the stickiness that doesn’t mean the material has degraded in any way does it? I pulled on the material pretty hard, and it seems durable still. I washed the tent and fly a few times which did nothing. Is there anything I can do about the stickiness like spray something on the material that will cover up the stickiness and create another coating? I know I can replace the tent floor with silnylon or whatever, but the stickiness isn’t irritating enough for me to do that. Thanks for any replies.

Here is the advice from Sea To Summit :
SOFT OR STICKY TENT FABRIC PU COATINGS. Here is the only possible treatment for this problem of old age softening of PU coatings. Carefully separate fabric layers if they have 'blocked' together. It may not be possible to do this without some coating damage. Set your domestic iron on cotton, non-steam. With a piece of clean photocopy paper (80gsm or heavier) always between the iron and the fabric, work carefully over all the fabric. Keep moving to avoid excessive heating. Ironing will harden the coating and drive out moisture. If parts of the coating are damaged or missing (hold the fabric up to the light to see this most easily) it is possible to smear Seamgrip® over these areas. If they are extensive this may not be practical. Whether you Seamgrip or not, finish by spraying the coated face of the fabric with a silicon or Teflon based water repellent. Your specialist outdoor store will have a suitable product. As you should always do, store the tent unrolled, coated sides out to minimise self contact.

http://www.seatosummit.com.au/techinfo.php?Area=tenttech&ArticleName=DIY%20Tent%20Repairs

Franco