1 Install ceramic tile floor to match shower-Average prices for installation are between $11 to $22 per square foot; 2  A light/fan combination-Averages at $180 and one hour of installation; 3  Insulate and re-finish ceilings and walls-Fiberglass wall insulation with R-30 value will cost $2.25 per square foot. Many homeowners are under the impression that a tiled option is always the most costly choice, but the average builder-grade shower pan is actually going to come at a cost of $300 while a well-made tile floor will come in at only $2 per square foot;