Trapped Ceiling-Cavity Water Load and Collapse Screen
The distributed load (a foot of water is 62.4 psf), total weight.
Example
You enter
- Bulging / saturated ceiling area (ft²) 20
- Average trapped water depth (in) 2
- Drain-first screen load (psf, editable) 5
You get
- Distributed load 10.4 lb/ft^2
- Total trapped weight 208 lb
Details, formula, and sources
The distributed load (a foot of water is 62.4 psf), total weight, and volume of water trapped overhead in a sagging ceiling cavity, with a drain-before-entry screen. The threshold is an editable screen value, not a code capacity - the fastening, span, and a structural engineer govern; this decides whether to punch-drain from a safe distance before anyone works beneath the bulge.
load_psf = (avg_depth_in/12) x 62.4; weight_lb = pooled_area_ft2 x (avg_depth_in/12) x 62.4 = volume_gal x 8.34; volume_gal = pooled_area_ft2 x (avg_depth_in/12) x 7.48052; drain_first = load_psf > threshold_psf.
Hydrostatic load and water density (62.4 lb/ft^3, 8.34 lb/gal, 7.48052 gal/ft^3) by name; ANSI/IICRC S500 safety practice. Not edition-bound.
Water is ~62.4 lb/ft^3, so a foot of depth is 62.4 psf and an inch is 5.2 psf. The densities are public constants.
Estimate. AHJ and licensed professional govern.
Field names used by the API: pooled_area_ft2, avg_depth_in, threshold_psf, load_psf, water_weight_lb
- Water density ~62.4 lb/ft^3, 8.34 lb/gal, 7.48052 gal/ft^3pure-math.js convention
- Threshold the drain-first load (default 5 psf) is an editable, conservative screen, not a structural ratingANSI/IICRC S500 safety practice
- Scope a safety screen for trapped overhead water; the wet gypsum's fastening and a structural engineer govern collapseANSI/IICRC S500