we have just built a house and are finding no options for a shower base, we wanted to go tile base but was recommended against due to possible leakage, so we were told we need to by a synthetic marble base... our shower is 4' wide x 5' deep is this the only solution, if so is there anything that needs to be done under the base? is it still possiblt to put a seat in the shower area. If so does it go up to the base or should it be built in the base. please give recommendations we are as the base is approx $3000 plus tax and install.... also another reason why they recommended against tile is we built a log home there is constant movement from the logs