I want to build a tile-topped table for our front-porch. The tile area will be 36x36 in. I plan a hardwood edge around it. It won't get rained on but will see large temperature extremes (live in Illinois, we had -27 degrees F when I first got here, to +100 on some days). Main use of table will be for eating. I started to read up on this topic using google groups and this group, but still have some questions. (1) Tile base: the overwhelming preference seems to be for plywood (rather than particle board, MDF). However, there are mixed opinions on whether one needs a cement-type board between the tile and plywood. Any comments on whether I need this, for this size table? Also, much of the plywood I have seen at Home Depot, Menards is not exactly flat. How do I deal with that? (2) Should add some cross braces below the plywood for support, for this size table? (3) Expansion/contraction of the wood. Any advice for dealing with this? Should I make an over-sized groove in the hardwood frame for the tile base so it "floats" -- but is that not a recipe for cracked grout along the edges?
Any help appreciated. Thanks! Adriaan