Roof Coating Coverage and Cost Calculator

ANA›Life Services Authority›National Calculator Authority›Roof Coating Coverage and Cost Calculator

.calc-container { max-width: 640px; margin: 2rem 0; padding: 1.5rem; background: #fff; border: 1px solid #ddd; border-radius: 8px; box-shadow: 0 1px 3px rgba(0,0,0,0.06); font-family: system-ui, -apple-system, sans-serif; } .calc-container h3 { font-family: Georgia, serif; font-size: 1.15rem; color: #1a1a1a; margin-bottom: 1rem; padding-bottom: 0.5rem; border-bottom: 2px solid var(--ac, #3d5a80); } .calc-row { display: flex; align-items: center; gap: 0.75rem; margin-bottom: 0.75rem; flex-wrap: wrap; } .calc-row label { min-width: 160px; font-size: 0.9rem; color: #333; font-weight: 500; } .calc-row input[type="number"], .calc-row select { flex: 1; min-width: 120px; max-width: 200px; padding: 0.5rem 0.6rem; border: 1px solid #ccc; border-radius: 4px; font-size: 0.9rem; font-family: system-ui, sans-serif; color: #1a1a1a; background: #fafaf8; } .calc-row input:focus, .calc-row select:focus { outline: none; border-color: var(--ac, #3d5a80); box-shadow: 0 0 0 2px rgba(26,74,138,0.12); } .calc-row .unit { font-size: 0.82rem; color: #888; min-width: 30px; } .calc-btn { display: inline-block; margin-top: 0.5rem; padding: 0.55rem 1.5rem; background: var(--ac, #3d5a80); color: #fff; border: none; border-radius: 4px; font-size: 0.9rem; font-weight: 600; cursor: pointer; font-family: system-ui, sans-serif; } .calc-btn:hover { opacity: 0.9; } .calc-result { margin-top: 1.25rem; padding: 1rem 1.25rem; background: #f0f6fc; border-left: 3px solid var(--ac, #3d5a80); border-radius: 0 6px 6px 0; display: none; } .calc-result.visible { display: block; } .calc-result-label { font-size: 0.78rem; text-transform: uppercase; letter-spacing: 0.06em; color: #666; margin-bottom: 0.25rem; } .calc-result-value { font-size: 1.6rem; font-weight: 700; color: var(--ac, #3d5a80); } .calc-result-detail { font-size: 0.85rem; color: #555; margin-top: 0.5rem; line-height: 1.5; } .calc-note { margin-top: 1rem; font-size: 0.8rem; color: #888; font-style: italic; } .calc-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 0.75rem; margin-top: 0.75rem; } .calc-grid-item { padding: 0.6rem 0.8rem; background: #f8f9fa; border-radius: 4px; border: 1px solid #eee; } .calc-grid-item .label { font-size: 0.75rem; color: #888; text-transform: uppercase; letter-spacing: 0.04em; } .calc-grid-item .value { font-size: 1.1rem; font-weight: 600; color: #1a1a1a; } @media (max-width: 720px) { .calc-row { flex-direction: column; align-items: flex-start; gap: 0.3rem; } .calc-row label { min-width: auto; } .calc-row input[type="number"], .calc-row select { max-width: 100%; width: 100%; } .calc-grid { grid-template-columns: 1fr; } } .calc-chart { margin: 1rem 0; text-align: center; } .calc-chart svg { max-width: 100%; height: auto; } .calc-chart-legend { display: flex; flex-wrap: wrap; justify-content: center; gap: 0.6rem 1.2rem; margin-top: 0.6rem; font-size: 0.8rem; color: #555; } .calc-chart-legend span { display: inline-flex; align-items: center; gap: 0.3rem; } .calc-chart-legend i { display: inline-block; width: 10px; height: 10px; border-radius: 2px; font-style: normal; } .calc-related { max-width: 640px; margin: 2rem 0 1rem; padding: 1.25rem 1.5rem; background: #f8f9fa; border: 1px solid #e8e8e8; border-radius: 8px; } .calc-related h3 { font-family: Georgia, serif; font-size: 1rem; color: #1a1a1a; margin: 0 0 0.75rem; padding-bottom: 0.4rem; border-bottom: 2px solid var(--ac, #3d5a80); } .calc-related-list { list-style: none; padding: 0; margin: 0 0 0.75rem; display: grid; grid-template-columns: 1fr 1fr; gap: 0.4rem 1.5rem; } .calc-related-list li a { font-size: 0.88rem; color: var(--ac, #3d5a80); text-decoration: none; } .calc-related-list li a:hover { text-decoration: underline; } .calc-browse-all { margin: 0.5rem 0 0; font-size: 0.9rem; font-weight: 600; } .calc-browse-all a { color: var(--ac, #3d5a80); text-decoration: none; } .calc-browse-all a:hover { text-decoration: underline; } @media (max-width: 720px) { .calc-related-list { grid-template-columns: 1fr; } }

Roof Coating Coverage and Cost Calculator

Estimate the total gallons of roof coating required and the overall material cost based on your roof dimensions, coating spread rate, number of coats applied, and price per gallon.

Roof Length (ft)

Roof Width (ft)

Roof Pitch (rise:12 run, e.g. 4 for 4:12)

Enter 0 for a flat roof. Pitch adjusts the actual surface area.

Coating Spread Rate (sq ft per gallon)

Typical elastomeric coatings: 50–150 sq ft/gal per coat.

Number of Coats

Waste / Overlap Factor (%)

Recommended 10–15% for edges, overlaps, and absorption.

Price per Gallon ($)

Container Size (gallons)

Coating is typically sold in 1, 5, or 55-gallon containers.

Calculate

function rooCalc() { var resultDiv = document.getElementById('roo-result');

var length = parseFloat(document.getElementById('roo-length').value); var width = parseFloat(document.getElementById('roo-width').value); var pitch = parseFloat(document.getElementById('roo-pitch').value); var spread = parseFloat(document.getElementById('roo-spread').value); var coats = parseInt(document.getElementById('roo-coats').value); var waste = parseFloat(document.getElementById('roo-waste').value); var price = parseFloat(document.getElementById('roo-price').value); var galSize = parseFloat(document.getElementById('roo-galsize').value);

// --- Validation --- if (isNaN(length) || length 24) { resultDiv.innerHTML = 'Roof Pitch must be between 0 and 24.

'; return; } if (isNaN(spread) || spread 50) { resultDiv.innerHTML = 'Waste Factor must be between 0% and 50%.

'; return; } if (isNaN(price) || price 0) ? (totalCost / roofArea) : 0;

// --- Output --- var html = '### Results '; html += 'Footprint Area' + footprintArea.toFixed(1) + ' sq ft'; html += 'Pitch Multiplier (' + pitch + ':12)' + pitchMultiplier.toFixed(4) + ''; html += 'Actual Roof Surface Area' + roofArea.toFixed(1) + ' sq ft'; html += 'Gallons per Coat (no waste)' + gallonsPerCoat.toFixed(2) + ' gal'; html += 'Total Coats' + coats + ''; html += 'Total Gallons (all coats, no waste)' + gallonsAllCoats.toFixed(2) + ' gal'; html += 'Waste / Overlap Factor' + waste + '%'; html += 'Total Gallons Needed (with waste)' + gallonsWithWaste.toFixed(2) + ' gal'; html += 'Container Size' + galSize + ' gal'; html += 'Containers to Purchase' + containersNeeded + ' container(s) (' + totalGallonsPurchased.toFixed(0) + ' gal total)'; if (price > 0) { html += 'Price per Gallon$' + price.toFixed(2) + ''; html += 'Total Material Cost$' + totalCost.toFixed(2) + ''; html += 'Cost per Sq Ft (surface area)$' + costPerSqFt.toFixed(3) + '/sq ft'; } html += '';

resultDiv.innerHTML = html; }

#### Formulas Used

1. Pitch Multiplier Pitch Multiplier = √(pitch² + 12²) / 12 Converts the horizontal footprint to the actual sloped surface area.

2. Actual Roof Surface Area Roof Area (sq ft) = Length × Width × Pitch Multiplier

3. Gallons per Coat Gallons per Coat = Roof Area ÷ Spread Rate (sq ft/gal)

4. Total Gallons (all coats, before waste) Total Gallons = Gallons per Coat × Number of Coats

5. Total Gallons with Waste Gallons with Waste = Total Gallons × (1 + Waste% ÷ 100)

6. Containers to Purchase Containers = ⌈ Gallons with Waste ÷ Container Size ⌉ (rounded up)

7. Total Material Cost Total Cost ($) = Containers × Container Size × Price per Gallon

8. Cost per Square Foot Cost/sq ft = Total Cost ÷ Roof Surface Area

#### Assumptions & References

Roof dimensions entered are the plan (footprint) dimensions, not the sloped surface dimensions.

Roof Coating Coverage and Cost Calculator

Roof Coating Coverage and Cost Calculator

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References

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