Hi Robert,

The glass lay up will depend on the thickness of your deck strips and the internal rib space. for rib space greater than 6" and strips milled 3/16" you may consider glassing inside at the deck. I had ribs spaced 8" and I used 1 layer of 3.2oz glass inside and 2 layers of 3.2oz on the top side of the deck. It feels solid enough however I can tell where the ribs are from the feel of the deck under my feet. I used 1 layer of the same on the bottom outside only. My deck was striped cedar 3/16" bottom was Paulownia 1/4" the rails were built hollow using Balsa 12'X30" board came out 32 lbs.

Clayton Plunkett