Built-Up Roofing Calculator

Ply count, bitumen, and surfacing for BUR system.

Roof Footprint (sqft)

Pitch (rise per 12 in)

Number of Plies

Waste Factor (%)

Tab to move between fields

Actual Roof Area (sqft)

2,000

Roofing Squares22

Base Sheet Rolls12

Ply Sheet Rolls34

Bitumen Required (lbs)2,971

Gravel/Aggregate (tons)4.4

Est. Material Cost ($)$2,916.00

How to Use This Calculator

Enter the roof footprint (sqft) and pitch (rise per 12 in).
Set the number of plies and waste factor (%).
Review calculated roof area, roof squares, base sheet rolls, ply rolls, and cap sheet rolls.
Add gravel surfacing or cap sheet quantities for the selected BUR specification.
Multiply roll quantities by unit costs to generate a material estimate.

How the result changes with Roof Footprint (sqft)

Roof Footprint (sqft): Horizontal projected area of the roof in square feet.
Pitch (rise per 12 in): Roof slope as inches of rise per 12 inches of run. BUR is typically low-slope (0.25-3).
Number of Plies: Number of felt/fiberglass ply layers (2-5). More plies = longer life. 3-4 is standard.
Waste Factor (%): Extra material for laps, overlaps, cuts, and waste. 10-15% is typical.

Actual Roof Area (sqft): True surface area accounting for roof pitch.
Roofing Squares: Roof area in roofing squares (1 square = 100 sqft).
Base Sheet Rolls: Number of base sheet rolls needed (200 sqft effective per roll).
Ply Sheet Rolls: Total felt/fiberglass ply rolls across all layers.
Bitumen Required (lbs): Total hot asphalt or cold adhesive including interply and flood coat.
Gravel/Aggregate (tons): Surfacing aggregate for the flood coat layer.
Est. Material Cost ($): Rough material cost estimate (labor not included).

Identify Input Parameters
4 parameters
Roof Footprint (sqft) = 2000, Pitch (rise per 12 in) = 0.25, Number of Plies = 3, Waste Factor (%) = 10 = 4 input(s) provided
Calculate Actual Roof Area
Actual Roof Area = footprintSqft * pitchFactor
2000 = 2000
Calculate Roofing Squares
Roofing Squares = roofAreaWithWaste / 100
22 = 22
Calculate Base Sheet Rolls
Base Sheet Rolls
12 = 12