House Wrap Calculator — m, rolls, cost
How to use this calculator
Type building perimeter and wall height, a single wall, or net m² already taken off the plans. Gables get added on top, doors and windows come out, then the calc adds shingle-lap overlap and a waste %. Pick a preset to load a real house footprint.
Seam tape — 50-75 mm tape for all horizontal and vertical seams, ~55 m per roll.
Fasteners — cap nails or cap staples, ~10 per m² of wrap, 1000 per box.
Cost — per roll of wrap, tape, and fastener box. Select currency below.
Saved Calculations
| Time | Method | Net m² | Rolls | Cost |
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How to Calculate House Wrap
House wrap (a weather-resistive barrier, WRB; EN 13859-2 wall underlay) is fixed over exterior sheathing before cladding to shed bulk water and limit wind infiltration. Take perimeter × wall height for gross wall area, add triangular gable areas (½ × base × peak height), then deduct doors (~1.86 m² each) and windows (~1.39 m² each). The overlap factor adds material consumed by the shingle-lapped horizontal and vertical seams, and the waste allowance covers cuts at corners, around flashed openings and torn courses.
Formulas
Gross area = perimeter × height + gable areas. Net area = gross − openings. Overlap factor = roll area ÷ [(roll width − horiz. overlap) × (roll length − vert. overlap)]. Adjusted area = net × overlap factor × (1 + waste%). Rolls = ⌈adjusted area ÷ roll coverage⌉. Seam tape length ≈ horizontal seams + vertical butt joints; fasteners ≈ 10 cap nails or cap staples per m².
Roll Sizes
Common metric sizes: 1.5 m × 50 m (75 m²), 2.8 m × 50 m (140 m²), 3.0 m × 50 m (150 m²). For standard 2.4 m walls, a 2.8 m or 3.0 m wide roll wraps the full story height in one course with overlap top and bottom; a 1.5 m roll runs two horizontal courses with a 15 cm shingle lap. Pair this with the wall insulation calculator and vapour barrier calculator to complete the wall assembly.
FAQ
How much overlap? Minimum 15 cm horizontal (shingle-lap so upper course laps over lower), 15–30 cm at vertical butt seams per manufacturer specifications; double the lap over inside corners. How many fasteners? Roughly 10 cap nails or cap staples per m² of wrap, spaced 300–450 mm along studs and 150 mm at seams. Do I need seam tape? Yes — tape all horizontal and vertical seams, tears and penetrations with manufacturer-approved tape for a continuous air and water barrier. For roof and attic assemblies use the roof insulation calculator; for an air-seal upgrade compare spray foam.
On install day
Three things that blow the takeoff. Inside corners — EN 13859-2 and most manufacturers want the membrane to lap continuously around inside corners by a full 300 mm; if you cut at the corner you create a vertical seam that has to be taped and counter-flashed. Window flashing sequencing — the wrap goes over the sill flashing and behind the jamb/head flashing (reverse-shingle), not the other way around; getting it backwards is the #1 callback on a WRB job. UV exposure — Tyvek, Delta, Solitex and most spunbonded wraps are warranted for ~3–4 months of exposure; if cladding is delayed past that, expect chalking and demand a re-wrap. Budget €4–9/m² installed for the wrap itself in 2025 EU (material €1–2/m², the rest is labor + tape + caps); a 140 m² single-story house typically runs €350–900 in wrap and accessories. Pair this with a finish takeoff and the wall insulation calculator to close out the envelope.
