And combining that with using the maximum 1 2 per foot of slope on the short 19 run 1 2 per foot times 19 that d give you just a tad over 3 4 of drop.
Minimum slope for shower floor.
The membrane is typically referred to as a shower pan.
If the slab elevation at the trench drain is within 3 4 inch of the plan elevation and the slab top elevation farthest from the drain is also within 3 4 inch of plan elevation the slab.
My contractor has just ripped out my shower floor because it was very uneven.
A 2 slope will probably ensure better drainage we could also find no slope tolerance for use when a floor slope is specified.
This includes tiling and gradients of bathroom floors including shower recesses.
I have found several references for 1 4 in per 12 in run.
I asked for the minimum slope and it looks like it is sloped 1 and 1 4 inch for 22 inches from left to right.
The recommended ratio of fall within showers is between 1 60 and 1 80.
A depth of 42 is a significant improvement and 48 is even better.
Both methods require that the floor be sloped 1 4 to 1 2 per foot from perimeters to a drain.
Mortar bed and thin bed.
Aci 117 90 standard specifications for tolerances for concrete construction and materials gives a level alignment tolerance of 3 4 inch for top of slab elevation of slabs on grade.
36 should be considered the minimum depth for any curbless shower.
Two common methods are used to waterproof showers.
Flush transition between the room and the shower floor requires a recessed subfloor in the shower area.
Had your tiler gone for the minimum allowed slope on the 3 run you d have 1 4 per foot times 3 or 3 4 of drop.
The larger the shower the easier it is to gradually slope the shower floor to the drain and contain water.
The mortar bed method requires a reinforced mortar bed approximately 11 4 over the waterproof membrane.