The Sheathing and Cost Estimate for a Roof calculator computes the number of 4x8 sheets (32 ft² each)
needed to cover the area of a basic gabled roof (see graphic) based on the ridge length, roof span, overhang and the pitch and applies the unit cost of a 4x8.
INSTRUCTIONS: Choose units and enter the following:
- (L) Ridge Length
- (S) Span of Roof
- (oH) Overhang
- (P) Pitch of Roof (choose one)
- (uP) Unit Price of Sheathing Boards (see Unit Pricing below)
Total Sheathing Board Cost (TC): The calculator returns the total price of sheathing boards in U.S. dollars. However, this can be automatically converted into other currency units via the pull-down menu.
The Math / Science
This formula is for a basic gable roof that is symmetric on both sides of the ridge. The pitch is defined as the rise over run, which is used to compute the pitch angle which is in turn used to compute the total surface area of the roof. Ideally, the total surface area could be divided by 32 square feet, the area a 4x8 can cover, in order to compute the number of 4x8 sheathing boards. But this would give an inaccurate number of 4x8s, since it implies a perfect utilization of partial pieces of the 4x8s, which is unreasonable. This model attempts to conform to construction habits of reasonable reuse and provides a conservative estimate (higher) on the number of 4x8s.
Unit Pricing
One should always use the local pricing available for constructions. However, for convenience a survey is periodically made for material costs. The following was identified for the price of 4x8 boards.
Most Recent Survey Results:
- Survey Date: 4/26/24
- Survey Store: Menards
- Price of 4x8 3/4" Plywood: $35.55 USD
- Price of 4x8 5/8" Plywood: $30.78 USD
- Price of 4x8 1/2" Plywood: $28.95 USD
- Price of 4x8 3/8" Plywood: $24.03 USD
- Price of 4x8 1/4" OSB: $18.98 USD
- Price of 4x8 3/4" Pressure Treated Plywood: $50.98 USD
- Price of 4x8 1/2" Pressure Treated Plywood: $44.84 USD
Gable Roof Calculators
- Gable Roof Area: This computes the surface area of a gable roof based on dimensions and pitch.
- Trusses Needed for Roof: This computes the number trusses need for a roof including gabled roof.
- 4x8 Sheathing for Gable Roof: This computes the total surface area of a roof, the number of 4x8s and framing nails needed for a gabled roof based on the length, span, pitch and overhang.
- Gable Roof Sheathing Cost: This computes the number of 4x8 sheets (32 ft² each) needed to cover a gabled roof based on the ridge length, roof span, overhang and the pitch and applies the unit cost of a 4x8.
- Nails for Gable Roof Sheathing: This computes the approximate number of nails needed to nail 4x8 sheets to trusses or rafters on a roof based on the dimensions of the roof, spacing of nails on the edges and field of the 4x8, and whether blocking or clips are use.
- Purlins for Gable Roof: This computes the total number and length of purlins for a simple gable roof based on the ridge length of the roof, the roof pitch and the span of the roof.
- Metal for Gable Roof: This estimates the metal panels and trim needed for a metal roof for a simple gabled roof based on the roof dimensions.
- Metal Screws for Gable Roof: This computes the number of special screws needed for a metal roof.
- Shingles for Gable Roof: This computes the number of shingles (bundles), underlayment, ridge shingles, starter strip, and roofing nails for a gable roof.
- Gable Roof Shingle Cost: This estimates to shingle a basic gable roof based on dimensions (length, span, pitch and overhang) and the unit price of a bundle of shingles.
- Underlayment for Gable Roof: This estimates the cost of underlayment to cover a basic gable roof based on the area of a roof computed from the dimensions (length, span, pitch and overhang) and the unit price underlayment material.
- Roofing Nails for Gable Roof: This estimates the number of roofing nails needed for a common gabled roof based on roof dimensions and wind conditions.
- Rafters for Gable Roof: This computes the total number of rafter boards (roof joists) for a gabled roof based on the ridge length, pitch and span. It also returns the length of the ridge board, and the length and number of rafter ties and collar ties.
- Rafter Length: This computes the length of the rafters based on the span, pitch and overhang.
- Gable Roof Geometries: This computes the length of rafters, pitch and cut angles, soffit and facia base widths of a gable roof.
- Weight of Snow on Roof: This computes the weight of snow on a gable roof based on roof dimensions, depth and type of snow.
Roof Types
