Uniform Plumbing Code related to shower pan construction.
"412. 8 When the construction of on-site built-up shower receptors is
Permitted by the Administrative Authority, one of the following means shall
Be employed:
(1) Shower receptors built directly on the ground:
Shower receptors built directly on the ground shall be watertight and shall
Be constructed from approved type dense, non-absorbent and non-corrosive
Materials. Each such receptor shall be adequately reinforced, shall be
Provided with an approved flanged floor drain designed to make a watertight
Joint in the floor, and shall have smooth, impervious, and durable surfaces.
(2) Shower receptors built above ground:
When shower receptors are built above ground the sub-floor and rough side of
Walls to a height of not less than three (3) inches (76 mm) above the top of
The finished dam or threshold shall be first lined with sheet plastic*,
Lead* or copper* or shall be lined with other durable and watertight
Materials.
All lining materials shall be pitched one-quarter (1/4) inch per foot
(20. 9 mm/m) to weep holes in the subdrain of a smooth and solidly formed
Sub-base. All such lining materials shall extend upward on the rough jambs
Of the shower opening to a point no less
Than three (3) inches (76 mm) above the top of the finished dam or threshold
And shall extend outward over the top of the rough threshold and be turned
Over and fastened on the outside face of both the rough threshold and the
Jambs.
Non-metallic shower sub-pans or linings may be built-up on the job site
Of not less than three (3) layers of standard grade fifteen (15) pound (6.8
Kg) asphalt impregnated roofing felt. The bottom layer shall be fitted to
The formed sub-base and each succeeding layer thoroughly hot mopped to that
Below. All corners shall be carefully fitted and shall be made strong and
Watertight by folding or lapping, and each corner shall be reinforced with
Suitable webbing hot-mopped in place. All folds, laps, and reinforcing
Webbing shall extend at least four (4) inches (102 mm) in all directions
From the corner and all webbing shall be of approved type and mesh,
Producing a tensile strength of not less than fifty (50) psi (344. 5 kPa) in
Either direction. Non-metallic shower sub-pans or linings may also consist
Of multi-layers of other approved equivalent materials suitably reinforced
And carefully fitted in place on the job site as elsewhere required in this
Section.
Linings shall be properly recessed and fastened to approved backing so
As not to occupy the space required for the wall covering and shall not be
Nailed or perforated at any point which may be less than one (1) inch (25.4
Mm) above the finished dam or threshold. An approved type sub-drain shall be
Installed with every shower sub-pan or lining. Each such sub-drain shall be
Of the type that sets flush with the sub-base and shall be equipped with a
Clamping ring or other device to make a tight connection between the lining
And the drain. The sub-drain shall have weep holes into the waste line. The
Weep holes located in the subdrain clamping ring shall be protected from
Clogging.
*Lead and copper sub-pans or linings shall be insulated from all conducting
Substances other than their connecting drain by fifteen (15) pound (6. 8 kg)
Asphalt felt or its equivalent and no lead pan or liner shall be constructed
Of material weighing less than four (4) pounds per square foot (19. 5 kg/m2).
Copper pans or liners shall be at least No. 24 B & S Gauge (0. 02 inches)
(0. 5 mm). Joints in lead pans or liners shall be burned. Joints in copper
Pans or liners shall be soldered or brazed. Plastic pans shall not be coated
With asphalt based materials."