The Underlayment for Gambrel Roof calculator computes the total surface area of a gambrel roof for underlayment based on the dimensions below and the estimated cost based on the area and unit price of underlayment material.
INSTRUCTIONS: Choose units and enter the following:
- (L) Ridge Length
- (S) Span of Roof
- (P1) Lower Pitch
- (P2) Upper Pitch
- (LH) Loft Height
- (oH) Overhang
- (UP) Unit Price of Underlayment
Gambrel Roof Underlayment and Cost (TC): The calculator returns the surface area for underlayment in square feet and the total cost of underlayment in U.S. dollar. However, these can be automatically converted to compatible units via the pull-down menu.
The Math / Science
The surface area of a gambrel roof is easy to compute based on the span, ridge length, overhang, attic height and two pitches of the roof. This calculator uses those specifications to compute the surface area of the roof. Once the surface area is known, the unit pricing (cost per square foot of underlayment) can be easily applied.
Underlayment comes in different types of materials and in different sizes of products measured in square feet. To compute the Unit Price per Square Feet CLICK HERE. A pop-up calculator will let you enter the product size (e.g., 265 square feet) and the total cost and will return the dollars per square feet.
Underlayment Pricing Data
The underlayment pricing data contains the following information in each record.
- Underlayment Pricing Survey Date: 1/2/23
- Underlayment Pricing Survey Store: Lowes
- Price of Felt Underlayment: $0.12 USD/ft²
- Price of Polypropylene Underlayment: $0.36 USD/ft²
- Paper (red rosin) Underlayment: $0.03 USD/ft²
- Rubber Underlayment: $0.95 USD/ft²
- Rubberized Asphalt Underlayment: $0.61 USD/ft²
- Synthetic Underlayment: $0.08 USD/ft²
All pricing is in U.S. dollars per square feet of underlayment.
NOTE: Local pricing should ALWAYS, ALWAYS, ALWAYS be used! These price points are for estimation convenience only, and there is no guarantee on the prices of the product nor of their availability at the listed price.
Underlayment Calculators
- Underlayment for a Gable Roof
- Underlayment for a Hip Roof
- Underlayment for a Gambrel Roof
- Underlayment for a Shed Roof
Gambrel Roof Calculators
- Gambrel Roof Surface Area: This computes the total surface area of a gambrel roof, and the number of 4x8s and bundle of shingles needed for a roof based on the dimensions below.
- Trusses Needed for Roof: This computes the number of trusses needed for a roof based on the ridge length and spacing.
- Sheathing for Gambrel Roof: This computes the number of 4x8 sheets to cover a gambrel roof based on the dimensions of the roof. It also includes the number of framing nails needed to nail the sheets to the roof based on whether clips are used or blocking.
- Gambrel Roof Shingles: This computes the number of bundles of shingles and ridge shingles needed for a gambrel roof based on the dimensions and bundle coverage.
- Roofing Nails for Gambrell Roof: This computes the number of roofing nails to shingle a gambrel roof based on the dimensions and wind conditions.
- Underlayment for Gambrel Roof: This computes the total surface area of a gambrel roof for underlayment based on the dimensions below and the estimated cost based on the area and unit price of underlayment material
- Purlins for Gambrel Roof:
This computes the length and number of rows of purlins needed for a gambrel roof based on the dimensions - Metal Panels for Gambrel Roof: This computes the length and number of vertical metal panels needed for a gambrel roof based on the dimensions. It also provides the length of the trim pieces.
- Horizontal Siding for Gambrel Wall: This compute the number of horizontal siding panels (e.g., vinyl or cedar) for a wall under a gambrel shaped roof line.
- Screws for Gambrel Metal Roof: This computes the number of screws to attach metal panels needed for a gambrel roof based on the dimensions. It also includes the total square feet and the number of metal screws needed at 0.75 screws per square foot.
- Metal Panels for Gambrel Wall: This computes the number of vertical siding panels, their lengths and the total length of vertical panels on a wall under a gambrel roof. It also includes the total square feet and the number of metal screws needed at 0.75 screws per square foot.
- Gambrel Pitch Angles: This computes the upper and lower pitch angles and rafter lengths bases on the span, total height, and height and width of the loft.
- Gambrel Rafter Lengths: This computes the upper and lower rafter lengths, loft width and total height based on the upper and lower pitch, span and loft height.
- Gambrel Angle: Compute the interface angle where the two pitched surfaces meet on the roof.
- Screws for Metal Siding Gambrel End Wall: Computes the number of metal panel screws needed for vertical metal panels on a wall under a gambrel roof.