SettingsSettings for this calculationUS
The total length of eave needing protection.
Measure along each eave that needs ice & water shield and add them together.
Tools needed: Tape measure or measuring wheel, Ladder
How far up the roof slope the membrane needs to extend from the eave.
Many codes require coverage extending at least 24 in inside the exterior wall line — on a sloped roof this often means 2 or more roll-widths, so this can exceed a single 36 in roll's width.
Ice & water shield rolls needed
1 roll
Required coverage width and whether ice & water shield is code-mandated in your area both depend on local climate zone rules — check your local building code before finalizing coverage width.
- Coverage area needed
- 161.7 sq ft
They open the calculator with your figures already in it
Ice & Water Shield Calculator: 1 roll — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
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How this was calculated
Formula source(s)
- A standard self-adhered ice & water shield roll (36 in wide) covers approximately 200 sq ft; area = eave length x membrane width
Inputs used
- Total Eave Length
- 49 ft
- Coverage Width From Eave
- 36 in
Intermediate steps
- Coverage area needed
- 161.7 sq ft
Confidence note: Required coverage width and whether ice & water shield is code-mandated in your area both depend on local climate zone rules — check your local building code before finalizing coverage width.
What this calculation does not cover
- The 10% uplift is spent on laps before it ever reaches waste. Self-adhered membrane laps at the manufacturer's figure — commonly 3 to 4 in (75 to 100 mm) on a side lap and 6 in (150 mm) on an end lap — so a 36 in (915 mm) roll nets about 33 in of covered deck, roughly 9% gone before a knife touches it, and a long eave loses more again at each end joint. Everything cut off at a hip, a rake or a corner comes out of what is left.
- Only an eave strip is ever returned. Where a roof falls below its covering's minimum slope — many asphalt shingle systems stop at 2:12 — the remedy is usually not a wider eave course but membrane or doubled underlayment over the entire deck, and low-pitched porch roofs, shed extensions and dormer tops are exactly where that comes up. A whole-deck area is a different sum from an eave length times a width.
Estimated cost — your price
This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.
Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.
Sources checked 2026-09-06 · in the site-wide review of 2026-09-06 · v1.0.1
Regulatory standards & verification citations1
- A standard self-adhered ice & water shield roll (36 in wide) covers approximately 200 sq ft; area = eave length x membrane width
Cite this page
Your workspace
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Tools and safety for this job
To lay the roof underlay. Generic types, no brands, no prices.
Protection this work requires
- Most fatal falls on small jobs are from under three metres: use a tower or a ladder tied at the top, and never work off the top two rungs.
- Knives cause more site injuries than any power tool: cut away from your body, change blades often, and wear cut-resistant gloves to EN 388 level C for repeated cutting.
Show the 3 tools this job needsHide tools
Essential
Tape measure
Utility knife
Recommended
Staple gun
Also needed as materials: replacement blades, staples.
what each roofing tool is for, and the spec that decides which to buy where one does.