Self-Leveling Underlayment Bag Count
Self-leveling underlayment (SLU) bags, where the yield depends on the average pour thickness.
Example
You enter
- Area to pour (ft²) 500
- Average pour thickness (in) 0.25
- Bag yield (square-foot-inches) 6.25
- Waste allowance (percent) 5
You get
- Neat (no waste) 20.0 bags
- Bags to order 21
No published worked example is on file for this calculation. It is checked against a hand-worked derivation of its method and an independent reference test.
Details, formula, and sources
ScopeNeat bags = area x thickness / bag yield (square-foot-inches); bags = ceil(neat x (1 + waste)). 500 sf poured at 1/4 in average, on a 6.25 sf-in bag yield, is 20 bags neat - 21 with waste; a deeper 1/2 in average doubles it to 42. The average thickness drives the order, so a low floor with deep spots eats material. SLU sets fast - stage bags first.
Formula or tableneat_bags = area_sf x avg_thickness_in / bag_yield_sf_in; bags = ceil(neat_bags x (1 + waste_pct/100)).
Source and editionSelf-leveler bag-count identity by name (volume of underlayment over the per-bag yield, plus waste); first-principles arithmetic.
Free accessThe bag-count arithmetic is public quantity geometry; the bag yield comes from the product's coverage rating.
What governsEstimate. AHJ and licensed professional govern.
API field namesarea_sf, avg_thickness_in, bag_yield_sf_in, waste_pct, neat_bags, bags
- Bag yield the product's coverage in square-foot-inches (~6.25 sf-in, i.e. 50 sf at 1/8 in)SLU manufacturer
- Average thickness the average pour depth from a floor-flatness survey; deep spots raise itfield survey