HomeExpertly
www.homeexpertly.com

Ice & Water Shield Calculator

Estimate how many rolls of ice-and-water shield you need to protect a roof's eaves, valleys and other vulnerable spots. Enter the total eave length and how far the shield runs up the slope, the valley length and width, and any extra area — then add a waste allowance for laps and a price per roll. You'll get the total coverage area, the number of rolls (rounded up to whole rolls) and the material cost, with a by-section breakdown, a by-coverage-width table, a chart, and a downloadable PDF report.

US feet and inches. Coverage = eave length × coverage width + valley length × valley width + other area, plus a waste allowance for side and end laps, divided by the roll coverage and rounded up to whole rolls. Most US codes require ice-and-water shield from the eave edge to at least 24 inches inside the exterior wall line, and in all valleys; cold-climate and local requirements vary. Confirm the required coverage, roll size and lap allowance with your supplier and building department. An estimate, not professional advice.
1 Eaves
ft
2 ft
3 ft
6 ft
ft
Eave area = eave length × coverage width. A 36-inch roll covers 3 ft up the slope in one course.
2 Valleys & extras
ft
ft
sq ft
Valley area = valley length × valley width. Add any penetrations, rakes or low-slope areas separately.
3 Roll & cost
sq ft
$
%
Rolls are rounded up to whole rolls. Overlap at laps is why a waste allowance matters.
Ice & water shield rolls
— rolls
Enter the eaves and valleys, then click Calculate
Coverage area
—
with waste
Rolls (with waste)
—
before rounding
Material cost
—
estimated
Shield summary
—
Enter the roof
We add up the eave, valley and extra areas, apply a waste allowance for laps, and round up to whole rolls.
Shield breakdown
Eave length—
Coverage width—
Eave area—
Valley length—
Valley area—
Other area—
Total coverage (base)—
Waste allowance—
Coverage with waste—
Roll coverage—
Rolls needed—
Total material cost—
Result summary
Rolls needed —
Coverage area —
Material cost —
Eave area —
Valley area —
Linear ft (36") —
Coverage by section
SectionLengthWidthArea
Enter the roof to see sections
By eave coverage width
Width up-slopeTotal areaRollsCost
Enter the roof to compare
Visualizations
Rolls needed by eave coverage width (highlighted = your width)