Estimating siding material is a straightforward process:

1. Calculate Total Area: Measure the length and height of each wall to be sided, calculate the area of each (L × H), and sum them to get the Total Square Footage. Subtract the area of large openings like garage doors, but typically not standard windows or doors.
2. Determine Material and Layout: Enter the actual width of your boards and battens. Decide on the on-center spacing for your battens (e.g., 12", 16", or 24").
3. Board Calculation: The calculator determines the total linear feet of boards required to cover your total square footage. `Linear Feet = (Total Area / Board Width in Feet)`.
4. Batten Calculation: The calculator estimates the total length of your walls (`Area / Height`) to determine how many vertical battens are needed based on your on-center spacing. `Linear Feet = Number of Battens × Wall Height`.
5. Apply Waste Factor: A waste factor (typically 10-20%) is added to both totals to arrive at the final amount you should order.

• Siding: Protective material attached to the exterior side of a wall of a house or other building.
• Square Footage: A measure of area, calculated by multiplying length by height. Siding is often estimated in squares (1 square = 100 sq ft).
• On-Center Spacing: The distance from the center of one regularly spaced framing member, like a batten, to the center of the next.
• Linear Feet: A measure of length. Lumber for siding is ordered in linear feet.

"When you calculate your total square footage, don't subtract for windows and doors unless they are very large, like a garage door or a picture window. The material you save by cutting out a standard window is usually consumed by the extra cuts and waste needed to trim around it. It's a wash, so just use the gross wall area." - Professional Siding Installer

"Your waste factor can change depending on the complexity of the job. A simple, flat wall might only need 10% waste. A wall with many gables, dormers, and windows could easily require 20% or more. Always err on the side of having too much material."

Example 1: Siding a 12' x 8' Shed Wall
Area = 12 * 8 = 96 sq ft. Using 1x10 boards (9.25") and 1x3 battens (2.5") with 16" on-center spacing and 15% waste.
Boards: `(96 / (9.25/12)) * 1.15` = `124.7 * 1.15` = 143.4 linear feet.
Battens: `ceil(12 / (16/12)) * 8 * 1.15` = `9 * 8 * 1.15` = 82.8 linear feet.

Example 2: A large 40' x 9' wall
Area = 360 sq ft. Using 1x8 boards (7.25") and 1x3 battens (2.5") with 12" on-center spacing and 10% waste.
Boards: `(360 / (7.25/12)) * 1.10` = `595.8 * 1.10` = 655.4 linear feet.
Battens: `ceil(40 / (12/12)) * 9 * 1.10` = `40 * 9 * 1.10` = 396 linear feet.

• Underestimating Waste: The most common and costly mistake. Running out of material mid-project can lead to delays and mismatched batches.
• Forgetting Gables: The triangular area of a gable needs to be calculated (`0.5 * base * height`) and added to the total square footage.
• Mixing Nominal and Actual Widths: Always use the actual measured width of the lumber for accurate calculations.
• Not Ordering Enough for a Single Batch: Try to order all your material at once to ensure it comes from the same mill run, which helps with consistency in color and texture.