Subfloor question for new deck and solarium

CM2U

My wife and I are going to have our current second story deck torn down and replaced. We are planning on installing a solarium over part of the deck, and therefore the deck foundation will be built with this in mind. My question is concerning the subfloor for the solarium. I plan to put in ceramic tile in the solarium and it would seem an incredible waste of time and materials to install deck planking where the solarium will sit (11 ft x 22 ft), only to turn around and overlay the deck planking with plywood and cement board for the ceramic tile. Is there a way I can skip the deck planking for the portion of the deck covered by the solarium?

CarpenterDon

You can delete the the decking boards and simply lay T-n-G ply over the floor joists. Then the backerboard and tile.

It is no different then doing any other floor (like in your house.)

CM2U

If I lay the plywood subfloor down and place the solarium on top of the subfloor, the edges of the plywood around the perimeter of the solarium would be exposed to the elements. Is there a way to do this and prevent the edges from being exposed? I thought about a "footprint" of pressure treated lumber where the solarium will sit and plywood on the interior. Any other ideas? Thanks again.

CarpenterDon

You can use P/T (pressure treated} plywood decking and dress the edges with a trim board of Cedar if you stain or seal it or Douglas Fir, Poplar, etc. if you are going to paint it.

That would be the best option.