Element Our standard Why it matters
WaterproofingSchluter-KERDI or ARDEX liquid membrane, full wet areaBonded system, warranted by the manufacturer
Shower slope2% (1/4" per foot) to drainCode minimum; anything flatter ponds
Backer boardCement board or foam board, never green boardPaper-faced gypsum fails in a wet wall
Exhaust fanSized to room volume, 8 air changes/hour, ducted outsideInsulated duct to stop condensation in the attic
Floor heat120 V mat, 12 W/sq ft, GFCI thermostatRuns about $3–5 a month in a main bathroom
Glass10 mm tempered, low-iron optionalTemplated after tile so the fit is exact