The Underlayment for Dormers calculator computes the square feet of underlayment needed for one or more roof dormers based on the dormer dimensions.
INSTRUCTIONS: Choose units and enter the following:
- (DD) Dormer Depth
- (DW) Dormer Width
- (P2) Pitch of Dormer Gable (choose pitch from list)
- (P1) Pitch of Main Roof (choose pitch from list)
- (n) Number of Dormers
- (UP) Unit Price of Underlayment per Square Foot (see below)
Underlayment for Dormers (SH): The calculator returns:
- (TA) Area: Total surface area of dormer(s) in square feet.
- (TC) Underlayment: Cost of underlayment materials in U.S. dollars.
Items with units can be automatically converted to compatible units via the pull-down menu.
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.
Dormer Calculators
- Surface Area of Dormers: This computes the roofing surface area for dormers based on the dimensions and number of dormers.
- Metal for Dormers: This computes the metal roof materials (panels, ridge cap and trim) for one or more roof dormers based on the dimensions
- Screws for Metal Dormers
: This computes the number of metal panels screws needed for one or more roof metal paneled dormers based on the dimensions. - 4x8s for Dormers: This computes the number of 4x8 sheathing needed for one or more roof dormers based on the dimensions.
- Shingles for Dormers: This computes the number of shingle bundles needed for one or more roof dormers based on the dimensions. It also includes ridge shingles, valley lengths for flashing, and roofing nails.
- Underlayment for Dormers: This computes the amount of underlayment needed and estimates the cost of underlayment materials.
- Roofing Nails for Dormers: This computes the number and weight of roofing nails needed for one or more roof dormers based on the dimensions.
- Purlins for Dormers: This computes the total number and length of purlins (roof support boards) for needed for one or more roof dormers based on the dimensions.
- Dormer Geometries: This computes the diagram measurements for a dormer based on the dimension.
Underlayment is installed beneath the outer roofing material (shingles or metal panels) and directly on top of the roof deck. Its primary purpose is to provide an extra layer of protection against water infiltration and to enhance the overall weather resistance of the roof.
Underlayment Calculators
- Underlayment for a Gable Roof: 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.
- Underlayment for a Hip Roof: Computes the surface area of a hip roof based on the dimensions and uses the surface area to compute the cost of underlayment based on the unit price (price per square feet) of underlayment material.
- Underlayment for a Gambrel Roof: 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.
- Underlayment for a Shed Roof: Computes the surface area of a shed roof and the cost estimate for underlayment based on the roof dimensions and a unit price of underlayment.
- Pyramid Roof Underlayment: Computes the surface area of a pyramid hip roof based on the dimensions, and uses the surface area to compute the cost of underlayment based on the unit price (price per square feet) of underlayment material.
- Underlayment of Dormers: This computes the amount of underlayment needed for one or more dormers and estimates the cost of underlayment materials.