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Calculate Roofing Materials (Canada)

Calculate roofing materials in Canada for 2026: shingles, ice & water shield, underlayment, drip edge, ridge cap and nails — sized to NBC 2020 and priced in CAD.

Roofing Material Calculator

Estimate every material you'll need to re-roof a gable house: shingles, underlayment, ice & water shield, drip edge, ridge cap, starter strip, and nails — plus a material-only cost estimate.

Roof area
1653
sq ft (with waste)
Squares
16.53
1 sq = 100 sq ft
Shingle bundles
50
Architectural (30-yr)
Starter bundles
1
~120 lf/bundle
Ridge cap boxes
3
ridge + hip
Underlayment rolls
2
synthetic, 10 sq/roll
Ice & water rolls
2
36" × 65 ft
Drip edge pieces
16
10 ft each
Valley flashing
0
10 ft pieces
Roofing nails
37
lbs (1.25" galv)
OSB decking
47
7/16" sheets (if re-decking)
Materials only
$3,457
add labor: $150–350/sq

What this Canadian roofing calculator estimates

This is a full-takeoff calculator for Canadian residential roofs, sized to NBC 2020 and the major provincial codes (OBC, BC Building Code, CCQ, Alberta Building Code). Plug in your dimensions and shingle choice and it returns:

  1. Roof surface area — building footprint (including soffit overhangs) multiplied by the slope factor, plus your chosen waste percentage
  2. Asphalt shingle bundles — 3 per square for architectural and 3-tab, 4 per square for premium designer profiles
  3. Starter strip bundles — sized to eave length (about 36 lineal metres / 120 lf per bundle)
  4. Hip and ridge cap boxes — sized to total ridge plus hip linear footage
  5. Synthetic underlayment rolls — 10 squares per roll for typical Canadian SKUs (RoofShield, Tiger Paw, IKO Stormtite); also reported in m² for metric-marked rolls
  6. Ice and water shield rolls — 36-inch by 65-foot rolls (Grace Ice & Water, IKO StormShield, BP Permastik), sized to the NBC 2020 36-inch interior eave requirement
  7. Drip edge pieces — 10-foot lengths along eaves and rakes
  8. Valley flashing — 10-foot pieces of W-valley or open-valley metal
  9. Roofing nails — pounds of 1.25-inch galvanized at 320 nails per square (or 480 for six-nail high-wind patterns)
  10. OSB or plywood decking sheets — only if you’re re-decking; 7/16-inch OSB at 32 sq ft per sheet
  11. CAD material cost estimate — at 2026 retail pricing, before labour, tear-off and tax

Step 1 — Measure the building footprint

Walk the perimeter and measure length and width to the drip edge — that means including your soffit overhang on every side. Most Canadian homes have a 12–24 inch overhang to keep snowmelt and ice-dam runoff away from the foundation, and that overhang counts as roof area you have to material.

For an L-shaped house, an addition, or a wing with its own roof, measure each rectangular section separately and sum the footprints. Aerial measurement reports (EagleView, GAF QuickMeasure, GeoEstimator Canada) give the most accurate numbers and are now standard on insurance-claim jobs across Ontario and Alberta. Otherwise you can step the perimeter — a typical adult stride is about 0.75 m (2.5 ft).

Step 2 — Determine the pitch

Canadian roofers still use the X/12 convention. Measure rise over a 12-inch run with a level and a tape, or use the roof pitch calculator to back-figure pitch from a photo and known reference dimension.

The slope factor turns footprint area into actual roof surface area:

slope factor = √(1 + (pitch / 12)²)

A 4/12 roof has a slope factor of 1.054 — the actual roof surface is 5.4% larger than the footprint. A 6/12 roof has 1.118 (about 12% larger), an 8/12 roof has 1.202 (about 20% larger), and a 12/12 has 1.414 (about 41% larger). Steep Atlantic Canada and Quebec storey-and-a-half roofs cost noticeably more per square foot of footprint because of this multiplier.

Step 3 — Set the waste percentage

Add waste before ordering. For Canadian conditions:

  • 12% for a simple gable with no valleys
  • 15% for a hip roof with four hip lines
  • 17–20% for a cut-up roof with dormers, gables, valleys and skylights
  • 20–22% for storey-and-a-half farmhouses and complex Victorian or Queen Anne profiles common in older Toronto, Halifax and Quebec City neighbourhoods

Canadian waste runs about 2% above US figures because the wider 36-inch NBC ice & water shield run forces more shingle cuts at the eave courses. Premium and designer profiles waste another 2–3% on top.

Step 4 — Measure your linear feet

The accessory materials are sized in linear feet, not square feet:

  • Ridge length — building length on a gable; building length minus building width on a hip
  • Hip length — four hip lines, each roughly √(half-width² × (1 + slope_factor²))
  • Valley length — measured along the valley itself, at the slope
  • Eave length — 2 × building length on a gable, full perimeter on a hip
  • Rake length — sloped edge of a gable, (half-width × slope_factor) per rake

Step 5 — Choose ice & water shield rows

Under NBC 2020 Section 9.26.6, ice barrier must extend from the eave edge to a point at least 36 inches inside the inside face of the exterior wall — that’s noticeably wider than the US IRC’s 24-inch requirement and almost always means two courses of 36-inch self-adhered membrane along every eave on a typical roof.

Practical row counts:

  • 2 rows (6 ft up the slope) — minimum for any Canadian eave, in line with NBC 9.26.6
  • 3 rows (9 ft up the slope) — required by some Ontario, Quebec and Atlantic municipalities on storey-and-a-half roofs and in heavy ice-dam zones (Sudbury, Trois-Rivières, Saguenay, Halifax)
  • Full coverage — high-end builds in northern BC, the Prairies and the territories sometimes spec 100% ice & water under metal panels

Always run ice & water in valleys and around chimneys, skylights and any penetration regardless of climate. Membrane at minimum 0.6 mm thick (CASMA-aligned spec) is the standard.

Step 6 — Read the results

The calculator outputs everything you need to walk into a Convoy Supply, Home Hardware, RONA, Castle, Home Depot Canada or a CRCA-member roofing wholesaler and place your order.

How the math works (Canadian worked example)

Reference example — a 30 × 40 ft house, 6/12 pitch, 1 ft overhang, IKO Cambridge architectural shingles, 12% waste, 2 ice & water rows along each eave:

Slope factor = √(1 + (6/12)²) = 1.118
Roof footprint = (30+2) × (40+2) = 32 × 42 = 1,344 sq ft
Surface area = 1,344 × 1.118 = 1,503 sq ft
With 12% waste = 1,683 sq ft → 16.83 squares (round to 17)
Bundles = 17 × 3 = 51 bundles

Eave length = 2 × 42 = 84 ft → starter bundles = ⌈84 / 120⌉ = 1
Ridge length = 42 ft → cap boxes = ⌈42 / 20⌉ = 3
Underlayment = ⌈17 / 10⌉ = 2 rolls (or about 158 m² in metric-marked SKUs)
Ice & water (2 rows × 84 ft) = 168 ft → ⌈168 / 65⌉ = 3 rolls
Drip edge = ⌈(84 + 74) / 10⌉ = 16 pieces
Nails = 17 × 320 = 5,440 → ⌈5,440 / 144⌉ = 38 lb

Pricing assumptions (CAD, 2026 retail)

These ranges reflect mid-2026 retail across Canadian suppliers — Home Depot Canada, RONA, Castle, Convoy Supply, Home Hardware. Source: CRCA 2026 Cost Guide, HomeStars and Renomii Q1 2026 contractor pricing, manufacturer MSRPs (BP Canada, IKO, GAF, CertainTeed Canada).

  • Architectural shingles: CAD $135–$175/square (calc default $155)
  • 3-tab shingles: CAD $105–$130/square (calc default $115)
  • Premium / designer shingles: CAD $295–$360/square (calc default $325)
  • Synthetic underlayment: CAD $105–$130/roll (10 squares)
  • Ice & water shield: CAD $115–$145/roll (36 in × 65 ft)
  • Drip edge: CAD $13–$17 per 10-ft piece
  • Valley flashing: CAD $30–$40 per 10-ft piece
  • Starter strip: CAD $58–$72/bundle
  • Hip & ridge cap: CAD $80–$105/box
  • 1.25-inch galvanized roofing nails: CAD $5–$7/lb

Add labour at CAD $200–$400 per square depending on region. Tear-off adds CAD $110–$170/square. Disposal at the landfill or transfer station adds CAD $55–$95/square in most Ontario and BC municipalities. Bin rentals in metro Toronto and Vancouver run CAD $400–$650 for a 14-yard skip.

Tax — what’s not in the contractor’s quote

Canadian roofing contractors typically quote materials and labour before tax. The applicable rate depends on province:

  • 5% GST — Alberta, Yukon, NWT, Nunavut
  • 5% GST + 7% PST — British Columbia
  • 5% GST + 6% PST — Saskatchewan
  • 5% GST + 7% RST — Manitoba
  • 5% GST + 9.975% QST — Quebec
  • 13% HST — Ontario
  • 15% HST — New Brunswick, Nova Scotia, Newfoundland & Labrador, PEI

On a CAD $20,000 re-roof in Ontario, that’s CAD $2,600 of HST on top. Always confirm whether your contractor’s number is “before tax” or “all-in” before signing.

Other Canadian roofing options to budget

Standing-seam metal. Growing share of the Canadian residential market — CRCA 2026 puts metal at about 15% of new residential roofs nationwide, higher in Quebec and the Maritimes. 24-gauge Galvalume runs CAD $480–$650/square supplied; 26-gauge screw-down ribbed panels (the “ag-panel” style common on rural Prairie homes) run CAD $310–$430/square. This calculator focuses on shingles — for metal, multiply panel area by 1.05–1.10 for laps and waste, and add concealed clips, butyl tape and matching trim.

Cedar shake. Still common on heritage and high-end homes in coastal BC and the Atlantic provinces. CAD $750–$1,100/square installed. Requires breathable underlayment (not synthetic) and is usually on roofs steeper than 6/12.

Slate. Niche but real in Ontario, Quebec and parts of Atlantic Canada. CAD $1,800–$3,200/square installed. 75-year+ service life. Requires upgraded structural framing — CRCA recommends a structural engineer review before re-roofing in slate.

Common Canadian mistakes to avoid

Forgetting the wider NBC ice & water run. US-based how-to videos and US calculators size ice & water for the 24-inch IRC requirement. NBC 2020 requires 36 inches inside the wall — almost always two courses, sometimes three. Don’t under-order.

Ignoring soffit overhangs. A 30 × 40 ft Canadian house with a typical 1 ft overhang is 1,344 sq ft of footprint, not 1,200.

Wrong nail length on a re-roof. Going over an existing layer in a single-tear jurisdiction (most of Canada permits one re-cover before mandatory tear-off under NBC 9.26.5) needs 1.75-inch nails, not 1.25-inch.

Buying staples. Most CASMA-aligned manufacturer warranties (BP Canada, IKO, GAF) void on stapled installs. Use only roofing nails.

Forgetting tax in your budget. A CAD $20K material-and-labour quote in Toronto is CAD $22,600 all-in. In Vancouver it’s CAD $22,400. Plan for it.

What this calculator doesn’t include

  • Roof ventilation (ridge vents, soffit vents, gable vents) — sized separately by attic CFA per NBC 9.19
  • Pipe boots, plumbing-stack flashings and bathroom-fan vents
  • Step flashing where the roof meets a wall
  • Eavestrough (gutters) and downspouts
  • Chimney saddles and skylight curb flashings
  • Snow guards (often required in BC interior, the Prairies and Quebec)

For a complete project budget, add 8–12% to the materials cost for these accessories, plus your labour, tear-off, disposal and provincial tax.

Sources: National Building Code of Canada 2020 Section 9.26; Ontario Building Code 2024 amendments; BC Building Code 2024; Code de Construction du Québec; CRCA 2026 Canadian Roofing Contractors Association cost guide; CASMA technical bulletins; HomeStars and Renomii Canadian roofing cost data Q1 2026; manufacturer installation specs (BP Canada, IKO, GAF Canada, CertainTeed Canada).

Frequently asked questions

How many bundles of asphalt shingles do I need per square in Canada?
Three bundles per square (100 sq ft) for standard 3-tab and architectural laminated shingles from BP Canada, IKO and GAF — the three brands that dominate the Canadian market. Premium designer shingles (IKO Royal Estate, GAF Camelot II, CertainTeed Presidential) are heavier and need four bundles per square. Order one extra bundle on top of your calculated total to cover cuts at hips, valleys and dormers, plus a few spares for future repairs. Most Canadian suppliers (Convoy, Home Hardware, RONA, Home Depot Canada) will let you return uncut bundles within 30 days.
How much waste should I budget for in Canadian conditions?
Canadian roofs run slightly higher waste than US equivalents — 12% for a simple gable, 15% for a hip roof, 17–20% for a cut-up roof with valleys and dormers. The reason is the wider ice & water shield runs required by NBC 2020 (36 inches inside the inside face of the exterior wall, vs. just 24 inches in the US IRC), which means more partial-shingle cuts at the eave courses. Premium and designer profiles waste another 2–3% on top because each piece is bigger and harder to reuse after a cut.
How wide does ice and water shield need to be under NBC 2020?
NBC 2020 Section 9.26.6 requires ice barrier on all roofs in areas where ice damming is a concern (effectively all of Canada south of the treeline). The membrane must extend from the eave edge to a point at least 36 inches inside the inside face of the exterior wall — a wider run than the 24-inch US requirement. On a typical 6/12 roof with 1 ft of soffit overhang, that means roughly two courses of 36-inch ice & water along every eave. Ontario's OBC, BC Building Code and Quebec's CCQ all adopt this requirement; check provincial amendments for any local variation.
How many nails per square for shingles in Canada?
Four nails per shingle is the Canadian default — about 320 nails per square for both 3-tab and architectural shingles. Six-nail patterns are required by manufacturer warranty in high-wind zones (coastal BC, Atlantic Canada, exposed Prairie sites) and on roofs steeper than 8/12. Use 1.25-inch (32 mm) galvanized roofing nails for new work or single-layer re-roof; switch to 1.75-inch (45 mm) when going over an existing layer. Plan on 2.2 lb of nails per square at 144 nails/lb. Staples are not permitted under most CASMA-aligned manufacturer warranties.
Do I need a permit to re-roof in Canada?
It depends on the province and municipality. Like-for-like asphalt shingle replacement is exempt from a building permit in most Ontario and Alberta municipalities, but Vancouver, Toronto and most Quebec cities require a permit if you're changing the deck, adding insulation, or replacing more than the membrane. Always check before tear-off — penalties for unpermitted work can include forced removal and re-inspection. Permit fees typically run $250–$700 for residential work. Trade licensing is also a factor: in Ontario you can DIY your own home but commercial work needs a licensed roofer.
How much does it cost to material a typical Canadian roof in CAD?
For a 1,500–2,000 sq ft single-storey gable home (about 17–22 squares of roof), expect CAD $3,800–$6,500 in materials for architectural shingles, synthetic underlayment, ice & water shield, drip edge, starter and ridge cap — excluding labour, tear-off and tax. Premium designer shingles roughly double the materials line. Add labour at CAD $200–$400 per square depending on region (Toronto, Vancouver and Calgary run high; Saskatchewan and the Maritimes run lower), plus tear-off at CAD $110–$170 per square. Source: CRCA 2026 cost guide; HomeStars and Renomii Q1 2026 contractor pricing.
Are roofing quotes in Canada usually tax-inclusive?
No — most Canadian roofing contractors quote materials and labour before tax, then add HST, GST or GST+PST as a separate line. Ontario, NB, NS, NL and PEI charge 13–15% HST. BC and Saskatchewan apply 5% GST plus 7% PST/SK 6% PST as separate items. Alberta, Yukon, NWT and Nunavut charge GST only at 5%. Quebec charges 5% GST plus 9.975% QST. On a CAD $20,000 re-roof you can be looking at CAD $1,000–$3,000 in tax depending on province, so always ask for an all-in figure before signing.
Should I include the soffit overhang when measuring my Canadian roof?
Yes — measure to the drip edge, not to the wall. A typical Canadian house has a 12–24 inch soffit overhang to keep meltwater away from the foundation, which adds significant area at the eaves. A 30 ft × 40 ft footprint with a 1 ft overhang is actually 32 ft × 42 ft = 1,344 sq ft of roof footprint, not 1,200 sq ft. Multiply that by your slope factor to get true surface area. Forgetting overhangs is the most common reason a Canadian DIY material order falls short by a bundle and a roll of underlayment.

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