I want to place ceramic tile over my 12' X 26' pressure-treated wood deck with boards spaced about 3/16" apart. Any suggestions on what I need to do differently than if I just re-tiled my kitchen/bath? I was thinking a thin layer of plywood (about 15/32") and then the tiles themselves. I'm not sure if there is a special kind of mortar for exterior use or not. Thanks.

We have just purchased our first home - Yeah! We're really excited and know that we have got a lot of "do it yourself" learning to do! Can anyone give us suggestions for a paticular project we want to do. The foyer of our house is tiled with a kinda really light terra cotta (almost on the pinkish side) large tiles. The grout is a beigeish color and is very dirty especially in the high traffic area down the center to the stairs. I have tried to clean it but the dirt only seemed to get a shade lighter! How do we brighten up the grout so it looks new, or at least an even shade all over the floor? My husband thought maybe we should remove the old grout and re grout the floor, but I'm hesitant as he knows even less about do it yourself projects than I do - he's excellent with computers and electronics, but a hammer mystifies him :-) Money is tight right now for us after buying the house and moving etc, that's why we need to do things ourselves. I really would appreciate any input or tips anyone can provide. Thanks in advance :-)