Pre-Sloped Receptor and Drain Installation
What this domain tests
This domain covers setting a prefabricated sloped receptor or building the sloped bed, and connecting the drain so the assembly drains fully. Concepts: slope requirement (commonly 1/4 in. per foot toward the drain, with a minimum that must never be reversed), drain clamping ring sequence, mortar bed consistency, and integration of the receptor with the drain flange.
Traps
- Confusing slope with flatness. A receptor can be flat but improperly sloped; a question may describe a pan that "looks fine" but ponds.
- Setting a prefabricated receptor on an unlevel or deflecting subfloor - the pan follows the substrate.
- Installing the clamping ring before the membrane, or over-tightening and cracking the flange.
- Forgetting that the drain's strainer must be removable for cleaning and that the finished floor meets the drain without a lip that traps water.
Rule of thumb
Measure slope from the farthest corner of the receptor to the drain. That distance sets the required drop; verify the drop at the perimeter, not mid-slope.
Worked example
A receptor is 4 ft from drain to the far corner. At 1/4 in. per foot, the perimeter must be at least 1 in. above the drain elevation. If the installed perimeter is only 3/4 in. high, the pan is under-sloped at the far corner even though the near side looks correct - a classic question trap.