This question was cross posted on T & T, because there are readers not on T & T on this list, I will post my answer here also. Roll out several layers of epoxy first. Then use monel staples to fasten the glass cloth to the core. Then roll out the resin on the cloth--repeat as necessary. You can start with more layers before the first layer is dry. Better have some plastic down. If the core is foam, how badly was it damaged. This may be why the deck is spongy. You should then replace the core. Vacuum bagging can also be used to adhere laminates to an overhead. I would prefer the vacuum bagging, but it takes a little more gear, and will be slightly more expensive Bob Austin