Asphalt Shingles (Basic 3-Tab) – $4.50/sq ft
Architectural Shingles – $6.50/sq ft
Metal Roofing (Steel/Aluminum) – $10.00/sq ft
Clay or Concrete Tile – $16.00/sq ft
Natural Slate – $22.00/sq ft
Estimated Roof Area:0 sq ft
Roofing Squares (10'x10′):0
Material & Labor Base:$0.00
Tear-off & Disposal:$0.00
Waste Factor (10%):$0.00
Total Estimate: $0.00
*Estimates include typical labor and materials. Prices vary by region.
function calculateRoofingCost() {
// 1. Get Input Values
var footage = parseFloat(document.getElementById('homeFootage').value);
var pitch = parseFloat(document.getElementById('roofPitch').value);
var materialPrice = parseFloat(document.getElementById('roofMaterial').value);
var includeTearOff = document.getElementById('tearOff').checked;
// 2. Validation
if (!footage || footage <= 0) {
alert("Please enter a valid home square footage.");
return;
}
// 3. Logic & Calculation
// Calculate actual roof surface area based on pitch multiplier
var roofArea = footage * pitch;
// Calculate waste (standard 10% for cuts and overlaps)
var wasteArea = roofArea * 0.10;
var totalBillableArea = roofArea + wasteArea;
// Calculate "Squares" (A square is 100 sq ft)
var squares = totalBillableArea / 100;
// Cost Calculations
var materialCost = totalBillableArea * materialPrice;
var tearOffCost = 0;
if (includeTearOff) {
// Assuming $1.50 per sq ft for tear off and disposal
tearOffCost = totalBillableArea * 1.50;
}
// Waste Cost is technically part of material/tearoff, but we break it down for visual logic if needed.
// For this specific display, we will calculate the waste cost portion separately for the breakdown
// Base area cost (without waste)
var baseAreaCost = roofArea * materialPrice;
var wasteCost = wasteArea * materialPrice;
// If tear off is included, waste also applies to tear off volume
if (includeTearOff) {
baseAreaCost += (roofArea * 1.50);
wasteCost += (wasteArea * 1.50);
} else {
tearOffCost = 0;
}
// Recalculating for the specific display variables to match standard contractor quotes
// Contractors usually quote: (Area + Waste) * Rate.
var displayMaterial = totalBillableArea * materialPrice;
var displayTearOff = includeTearOff ? (totalBillableArea * 1.50) : 0;
var totalCost = displayMaterial + displayTearOff;
// 4. Update DOM
document.getElementById('res-area').innerHTML = Math.round(totalBillableArea).toLocaleString() + " sq ft";
document.getElementById('res-squares').innerHTML = squares.toFixed(1);
document.getElementById('res-material').innerHTML = "$" + displayMaterial.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('res-tearoff').innerHTML = "$" + displayTearOff.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
// For the "Waste Factor" line item, we show the cost equivalent of that 10% extra area
var wasteValue = totalCost – (totalCost / 1.10);
document.getElementById('res-waste').innerHTML = "$" + wasteValue.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
document.getElementById('res-total').innerHTML = "$" + totalCost.toLocaleString(undefined, {minimumFractionDigits: 2, maximumFractionDigits: 2});
// Show results
document.getElementById('calc-results').style.display = "block";
}
Comprehensive Guide to Roofing Cost Estimation
Replacing a roof is one of the most significant investments a homeowner will make. Understanding the factors that drive roofing costs is essential for budgeting effectively and ensuring you receive a fair quote from contractors. Our Roofing Cost Calculator is designed to provide a realistic estimate based on industry-standard multipliers and material prices.
1. How Roof Pitch Affects Cost
The "pitch" or slope of your roof significantly impacts the total price. A flat roof is easier and safer to walk on, requiring less labor and safety equipment. Conversely, a steep roof (often found in Victorian or Tudor styles) requires special safety harnesses, scaffolding, and moves much slower, increasing labor costs.
Low Slope: Minimal increase in surface area compared to the home's footprint.
Moderate Slope: Standard for most suburban homes; increases surface area by roughly 15-20%.
Steep Slope: Can increase surface area by 35-50% and double labor costs due to difficulty.
Pro Tip: Most contractors measure roofing in "Squares." One Square equals 100 square feet of roof area. If your roof is 2,000 sq ft, you need 20 Squares of material.
2. Material Choices Breakdown
Your choice of material is the largest variable in the total cost.
Asphalt Shingles: The most common and affordable option. They typically last 15-25 years.
Architectural Shingles: Thicker and more dimensional than standard 3-tab shingles. They cost slightly more but offer better wind resistance and aesthetic appeal.
Metal Roofing: durable and energy-efficient. While the upfront cost is higher ($8-$14 per sq ft), they can last 50+ years.
Tile & Slate: Premium materials that are extremely heavy. Your home may require structural reinforcement to support them, adding to the cost.
3. The "Tear-Off" Factor
Many jurisdictions allow up to two layers of shingles on a roof. However, roofing professionals highly recommend a complete "tear-off" of existing materials. This allows inspectors to check the decking (wood sheathing) for rot or water damage. While tearing off the old roof adds approximately $1.00 to $2.00 per square foot, it prevents future structural failures and ensures your manufacturer warranty is valid.
4. Waste Factors
No roof is a perfect rectangle. Valleys, hips, ridges, and dormers require shingles to be cut, creating waste. A standard gable roof typically calculates 10% waste, while complex hip roofs may require 15-20% extra material to ensure full coverage.