Thanks Craig, but in fairness I was a cheque writer, though I looked in on the job almost every day, over 6 weeks of fortunately fine weather. Also, yours is an MT, not an IG. But, here goes.
What`s under the teak is some form of fiberglass sandwich. In between the top and bottom glass is almost certainly offcut teak blocks. I was lucky, I had an unexpected foam sandwich, if the wood is soft wet rotten it gets replaced. No soft areas is encouraging, I had just 2 small squares of wood sandwich, both soft and rotten.
Before that the teak planking gets removed. All those screws get unscrewed(don`t rely on the heads being good), and the teak gets levered/Fein tooled off,the glue removed, and if the substrate is ok, the screw holes get epoxy filled and faired, the whole surface gets faired, ready for your choice of new finish.
I assume that if the top layer of f/g comes off and the wood sandwich is replaced, there will be screw holes to seal in the bottom layer. I wonder if foam replacement would cost less than wood, I suspect yes, no teak to buy, less labor.
If the chosen new finish is painted f/glass you need 2 layers of f/g laid to restore stiffness, faired, and painted in nonslip. If you go with more teak (cost alert!! it is slow, labor intensive and expensive), one layer of f/g will do to restore the stiffness, plus fairing, and this time it gets glued not screwed, except maybe for the first plank, and around tight areas.
I did the bow in paint, and the sides and cockpit in teak.The painted areas can get hot, but f/g will cost much less, be much faster, and can be nicely finished.
You have to fix it or eventually you`ll lose the boat to water entry and rot. It sounds like you might be handy with DIY for this kind of work. You either need good weather or good protection of the work surface.
This could be a good time to think about access and tank replacement if indicated. Water entry is not good for tank tops.
Happy to answer any questions I can.
Island Gypsy 36 Europa "Doriana"