Shower Waterproofing Calculator

Membrane and drain system for tile shower installations.

Shower length (ft)

Shower width (ft)

Waterproofed wall height (ft)

Number of walls

Membrane type (1=liquid, 2=sheet)

Seam overlap (inches)

Tab to move between fields

Total membrane area (sq ft)

Floor/pan area (sq ft)9

Wall area (sq ft)72

Material needed (gallons or rolls)2

Seam tape needed (linear ft)25

Tape rolls needed1

Estimated material cost ($)$128.00

How to Use This Calculator

Enter Shower Length (ft) and Shower Width (ft) — the interior dimensions of the shower enclosure.
Set Waterproofed Wall Height (ft): standard showers require at least 6 ft, steam showers require full ceiling height.
Enter Number of Walls to waterproof (3 for alcove showers, 4 for freestanding).
Select Membrane Type (1=liquid-applied such as RedGard, 2=sheet membrane such as Schluter Kerdi).
Review Total Membrane Area (sq ft) and Material Needed (gallons or rolls) for your product order.
Check Seam Tape (linear ft) and Tape Rolls for corners and transitions, and Estimated Material Cost for budgeting.

How the result changes with Waterproofed wall height (ft)

Shower length (ft): Interior length of the shower enclosure in feet.
Shower width (ft): Interior width of the shower enclosure in feet.
Waterproofed wall height (ft): Height to waterproof on walls. Industry standard is full height (ceiling) for steam showers, or at least 6 ft for standard showers.
Number of walls: Number of shower walls to waterproof (3 for alcove, 4 for freestanding).
Membrane type (1=liquid, 2=sheet): 1 = liquid-applied (RedGard, HydroDefense) at ~57 sq ft/gal. 2 = sheet membrane (Kerdi) at ~108 sq ft/roll.
Seam overlap (inches): Overlap at seams per manufacturer specs. Typically 2 inches for sheet membrane.

Total membrane area (sq ft): Total area to waterproof including 10% waste factor.
Floor/pan area (sq ft): Shower floor area requiring waterproofing.
Wall area (sq ft): Total wall area to be waterproofed.
Material needed (gallons or rolls): Gallons of liquid membrane or rolls of sheet membrane required.
Seam tape needed (linear ft): Linear feet of seam/transition tape for corners and seams.
Tape rolls needed: Number of 33 ft seam tape rolls to purchase.
Estimated material cost ($): Approximate material cost based on average pricing.

Identify Input Parameters
4 parameters
Shower length (ft) = 3, Shower width (ft) = 3, Waterproofed wall height (ft) = 8, Number of walls = 3 = 6 input(s) provided
Calculate Total membrane area
Total membrane area = totalMembraneArea * 1.10
97 = 97
Calculate Floor/pan area
Floor/pan area = showerLength * showerWidth
9 = 9
Calculate Wall area
Wall area = avgWallLength * numWalls * wallHeight
72 = 72