Drywall Surface AreaSurface Area [sq ft or m²]
The total square footage or square meters of wall and ceiling planes requiring gypsum board coverage. Gross area is computed as 2 * (Length + Width) * Height for walls plus Length * Width for ceilings, minus door and window deductions.
Default: Net Area = Gross Walls + Ceiling - Openings
Standard Drywall Sheet SizingBoard Dimensions & Area [sq ft or m² / sheet]
The nominal dimensions of gypsum wallboards. North American residential standards are 4x8 ft (32 sq ft), 4x10 ft (40 sq ft), 4x12 ft (48 sq ft), and 54-inch x 12-ft boards (54 sq ft) specifically engineered for 9-foot ceilings. Metric standards are 1200x2400 mm (2.88 m²) and 1200x3000 mm (3.60 m²).
Default: 4x8 ft (32 sq ft) or 4x12 ft (48 sq ft)
Gypsum Board Thickness & Core TypeMaterial Gauge & Fire Rating [Inches or mm]
The cross-sectional board thickness: 1/4-inch (6.4 mm) for curved walls and double-layer overlays; 3/8-inch (9.5 mm) for repairs; 1/2-inch (12.7 mm) standard for residential interior walls and 16" o.c. ceilings; and 5/8-inch (15.9 mm) Type X fire-rated for garages, commercial demising walls, and 24" o.c. ceilings.
Default: 1/2" Regular (Walls) / 5/8" Type X (Garages)
Cutting Waste FactorGeometric Loss Percentage [10% to 20%]
The percentage of excess material needed to compensate for cut-offs, opening trimmings, and off-stud seams. Simple rectangular rooms require 10% waste; rooms with closets, alcoves, and soffits require 15%; complex vaulted spaces and stairwells require 20%.
Default: 10% Standard / 15% Moderate / 20% Complex
Joint Compound (Mud) VolumeCompound Consumption [Gallons, Pails, or Lbs]
The volume of ready-mixed joint compound (or dry powder weight) needed to tape joints, bed corner beads, and cover screw heads. Under ASTM C840 / GA-214 standards, Level 4 requires approximately 1.4 pails (4.5 gallons each) per 1,000 sq ft (~135-140 lbs). Level 5 skim coating adds an additional 0.7 pails per 1,000 sq ft.
Default: 1.4 Pails (4.5 gal) per 1,000 sq ft (Level 4)
Drywall Joint Tape AllowanceLinear Seam Coverage [Linear Feet or Meters]
The total linear footage of paper or fiberglass mesh tape needed to reinforce flat joints, butt seams, and inside corners. Average residential drywall requires approximately 35 to 40 linear feet of tape per 100 square feet of board surface (one 250-ft roll finishes ~650-700 sq ft of drywall).
Default: 35 lft tape per 100 sq ft drywall
Fastener Screw DensityFastener Quantification [Screws / Sheet or Lbs]
Under IRC and ASTM C840 standards, 1-1/4" Type W bugle-head screws spaced 12" to 16" on-center require approximately 32 screws per 4x8 sheet (~1 screw per square foot) and 40-48 screws per 4x12 sheet. One pound of 1-1/4" drywall screws contains approximately 300 to 330 screws, covering roughly 300 to 350 sq ft of drywall.
Default: 32 Screws / 4x8 Sheet (~1 lb / 10 Sheets)
GA-214 Levels of Gypsum FinishIndustry Quality Specification [Level 1 to 5]
The official Gypsum Association finishing classification: Level 1 (fire-taping in plenums/attics); Level 2 (garages/warehouses, tape embedded and 1 wipe over screws); Level 3 (substrate for heavy textures); Level 4 (standard painted walls with flat/eggshell paint); Level 5 (premium full surface skim coat for gloss paint or intense oblique lighting).
Default: Level 4 (Standard) / Level 5 (Premium Skim)
