⌂ RoofingCalculatorHQ

Roof Underlayment Cost Calculator

Estimate 2026 Canadian roof underlayment cost by line item: 15-lb felt, 30-lb felt, synthetic UDL (Titanium, RoofTopGuard, Tiger Paw), or full self-adhered SBS, with NBC 9.26.6-mandatory ice-and-water shield, drip edge, starter strip, tear-off, permit and disposal. Real 2026 CRCA and NBC 9.26 contractor rates.

Roof Underlayment Cost Calculator

2026 Canadian roof underlayment cost by line item — 15-lb felt, 30-lb felt, synthetic UDL (Titanium, RoofTopGuard, Tiger Paw), or full self-adhered SBS, with ice-and-water shield (NBC 9.26.6 mandatory minimum 900 mm past inside face of wall), drip edge, starter strip, tear-off, permit and disposal. Real 2026 CRCA and NBC 9.26 contractor rates.

Estimated underlayment cost
$4,323
Range: $3,675 – $5,188
underlayment + tear-off + ice & water + drip + starter + permit + disposal
Underlayment installed
$2,079
Tear-off
$1,144
Ice & water shield
$420
Drip edge
$480
Starter strip
$0
Disposal
$200

What this calculator estimates

This calculator gives you a line-by-line 2026 Canadian installed price for roof underlayment, the water-resistive layer that sits between the roof deck and the shingles, metal panels or membrane above. Whether you are re-roofing a 1,500 sq ft Maritime saltbox, replacing the deck on a 3,200 sq ft prairie two-storey, or specifying a new build to IKO Iron Clad Plus standards, the calculator follows the line-item structure that CRCA-member roofers use on real quotes:

  • Underlayment material — 15-lb felt, 30-lb felt, synthetic UDL, or full self-adhered SBS
  • Tear-off — removing the existing underlayment and load-out to bin
  • Ice-and-water shield — NBC 9.26.6 mandatory at eaves, plus valleys and penetrations, sized in linear ft
  • Drip edge metal — galvanised or aluminium L-shape at eaves and rakes
  • Starter strip — peel-and-stick or nail-down strip below the first course (warranty-required for many systems)
  • Municipal permit, disposal, weekend premium and extra labour

A C$780 minimum mobilisation fee applies in most Canadian metro markets even on small jobs, because re-roofing requires a 2-person crew with a roof jack, magnetic sweep, bin placement and tarping.

How to use it

  1. Enter roof area in square feet (use the actual roof surface, not the building footprint — multiply footprint by the pitch factor: 1.06 for 4/12, 1.12 for 6/12, 1.20 for 8/12, 1.30 for 10/12, 1.42 for 12/12).
  2. Pick underlayment type — 15-lb felt for budget builds, 30-lb felt for code-minimum on lower-pitch roofs, synthetic UDL for the modern industry standard, peel-and-stick for storm-prone Atlantic or historic full-coverage specs.
  3. Pick roof pitch — low (2/12 to 4/12) 1.0x, standard (5/12 to 9/12) 1.05x, steep (10/12 or higher) 1.25x for the harness, scaffolding and slowdown that steep work demands.
  4. Set scope — spot repair (20%), partial replace (50%), or full re-roof (100%).
  5. Set storey count — single-storey 1.0x, two-storey 1.18x, three-storey or higher 1.40x.
  6. Set access difficulty — easy (drive-up) 1.0x, moderate (ladder access) 1.10x, hard (cut-up roof, dormers, hoist) 1.30x.
  7. Enter ice-and-water shield length in linear feet (eave length plus valley length plus 10% for penetrations and overlaps).
  8. Enter drip edge length in linear feet (eave length plus rake length).
  9. Toggle starter strip if you want it priced separately, then enter starter length.
  10. Toggle tear-off, municipal permit, disposal, weekend premium, and any extra labour hours.

Typical 2026 Canadian underlayment cost ranges

These ranges reflect 2026 nationwide pricing from the CRCA Cost Survey, HomeStars and Renomii indicative rates, and Q1 2026 quotes from Toronto, Montreal, Vancouver, Calgary, Edmonton, Halifax and Winnipeg.

Underlayment line item (2,000 sq ft, single-storey, moderate access)2026 installed price
15-lb asphalt-saturated felt, full deckC$925 – C$1,400
30-lb asphalt-saturated felt, full deckC$1,275 – C$1,900
Synthetic UDL (Titanium UDL-50, RoofTopGuard II, Tiger Paw), full deckC$1,900 – C$2,650
Self-adhered SBS, full coverageC$4,800 – C$7,200
Ice-and-water shield strip at eaves and valleys (200 lf)C$420 – C$630
Drip edge metal, galvanised, eaves and rakes (200 lf)C$480 – C$680
Starter strip, peel-and-stick (200 lf)C$370 – C$520
Tear-off existing felt and load-out (2,000 sq ft)C$950 – C$1,330
Municipal building permit, full re-roofC$130 – C$300

Add 18 percent for two-storey, 40 percent for three-storey or higher. Add 10 to 30 percent for moderate to hard access. Add 25 percent for weekend or after-hours work.

Cost drivers

Underlayment material choice. This is the single biggest variable. Felt costs less per roll but weighs more (one 30-lb roll covers 200 sq ft vs 1,000 sq ft for a 10-square synthetic roll), takes longer to fasten, tears more easily, and has a 30-day UV exposure limit before it must be covered. Synthetic UDL roughly doubles the material cost but cuts installation labour by 30 to 40 percent and provides 90 to 180 days of UV exposure tolerance — a critical factor when bad weather delays the shingle layer in Maritime, Quebec and Pacific climates.

Pitch and harness time. Low-slope work (2/12 to 4/12) is fast — installers walk freely, rolls deploy quickly. Standard pitch (5/12 to 9/12) needs roof jacks. Steep pitch (10/12 and higher) requires fall-arrest harnesses, anchor points, slower deployment, and a productivity hit of roughly 25 percent.

Tear-off and deck inspection. Tear-off is rarely optional on a re-roof in Canada. The old underlayment is brittle, tears when shingles are pulled, and the deck must be inspected for rot, plywood delamination, fastener pull-through and ridge separation — all common in freeze-thaw climates. Budget C$0.52 per sq ft for tear-off and an additional C$1.05 per sq ft for any sheathing replacement.

Ice-and-water shield extent. NBC 9.26.6 minimum is the eave detail in cold-climate zones (effectively all of Canada except southwestern BC). Best practice extends the shield up the entire valley (a 900 mm strip down each valley centerline), around chimneys, plumbing stacks and skylights, and up the rakes by 450 mm in coastal Atlantic storm zones. A 2,000 sq ft roof with code-minimum eaves typically uses 100 to 140 lf of shield; best-practice usage runs 200 to 280 lf.

Drip edge integration. Drip edge is required by NBC 9.26.4 at all eaves and rakes for asphalt shingles. Spec is 26-gauge galvanised steel or 0.475 mm aluminium, 38 mm face minimum. The drip edge sits on top of the underlayment at the rake and below the underlayment at the eave (ice-and-water shield laps over the eave drip edge). Cost is roughly C$2.40 per linear foot installed.

Permit, disposal and storey logistics. Most Canadian municipalities require a roofing permit at C$130 to C$300 for re-roofs (Ontario and Quebec are typically required; Alberta and BC vary by municipality). Disposal of old material is C$0.10 to C$0.20 per sq ft depending on landfill-fee structure. Two-storey work adds 18 percent for ladder time and material handling; three-storey adds 40 percent.

Underlayment chemistry and what makes a good product

Asphalt-saturated felt is unwoven cellulose fibre saturated with asphalt. Modern code-listed felts meet ASTM D226 Type I (15-lb) or Type II (30-lb), or ASTM D4869 for organic-felt with improved tear strength.

Synthetic UDL is woven polypropylene or polyethylene with a slip-resistant top surface. Quality dimensions: tear strength (minimum 50 lbf per ASTM D4533), UV exposure rating, walkability friction rating, nail sealability, and lay-flat behaviour at temperature extremes (especially below -30°C). Major brands: IKO RoofGard-Cool Grey, BP RoofShield Plus, Malarkey Right-Start, GAF Tiger Paw, Owens Corning ProArmor, InterWrap Titanium UDL-50.

Self-adhered SBS membrane is rubberised asphalt with a polyethylene release film. Cap-sheet quality dictates UV tolerance and walkability. Major brands: IKO StormShield, BP NailGuard, Malarkey Arctic Seal, GCP Grace Ice & Water Shield, Henry Blueskin.

For a 25-to-50-year shingle system in a Canadian climate, specify a CCMC- or CRCA-listed underlayment matched to the system warranty tier, paired with a self-adhered ice-and-water shield at all eaves per NBC 9.26.6.

Canadian code references and authority sources

  • NBC 9.26.4 — drip edge / eaves trim requirement
  • NBC 9.26.6 — ice-and-water shield at eaves in cold-climate zones (mandatory for all of Canada except mild coastal BC)
  • NBC 9.26.10 — underlayment requirements for asphalt shingles
  • NBC 9.26.18 — re-roofing over existing material limits
  • CSA A123.3 — asphalt-saturated organic felt underlayment standard (Canadian)
  • CSA A123.5 — asphalt shingles standard
  • CSA A220 / CCMC — Canadian Construction Materials Centre evaluations for synthetic underlayment
  • ASTM D226 / D4869 / D8257 / D1970 — material standards (US standards adopted in Canadian practice)
  • CRCA Roofing Specifications Manual — installation reference, 2024 edition
  • WHMIS / WorkSafeBC / IRSST / WSIB — fall-protection rules for roof work

When each underlayment is the right choice

  • 15-lb felt — investor-grade rentals, sheds, garages, and other low-stakes installs where a 10 to 15-year shingle life is acceptable.
  • 30-lb felt — heritage restorations where the look and feel of traditional felt is specified, or low-pitch residential where extra weight resists wind lift during install.
  • Synthetic UDL — virtually every modern Canadian residential and light-commercial re-roof. The default choice for any 25-year-or-better shingle system, and especially valuable in Maritime and Pacific climates with construction-delay weather.
  • Full-coverage peel-and-stick — Atlantic Category 1 wind zones, low-pitch sections (2/12 to 4/12), wildfire-overlay regions in BC interior, and heritage full-spec restorations.

Bidding strategy and red flags

Always get three written bids that itemise underlayment brand, ice-and-water shield brand and linear footage, drip edge gauge and material, starter strip brand, tear-off scope, permit cost and bin fees. A bid that lumps “underlayment and accessories” into a single line item is a red flag. Confirm:

  1. The bidder uses the manufacturer’s branded underlayment matched to the shingle system warranty tier.
  2. The bid lists ice-and-water shield linear feet and confirms NBC 9.26.6 compliance for the eave detail.
  3. Drip edge gauge meets NBC 9.26.4 minimum (26-gauge galvanised or 0.475 mm aluminium, 38 mm face).
  4. The bid includes deck inspection time and a per-sheet rate for sheathing replacement.
  5. The bidder is CRCA-listed with a current liability policy, a 5-year workmanship guarantee, and (in Ontario) a Tarion Warranty Corporation registration if new build.

For deeper estimating, also use our roof replacement cost calculator, roof tear-off cost calculator, and ice dam risk calculator to cross-check a complete re-roof bid against your specific square footage and climate zone.

Frequently asked questions

How much does roof underlayment cost installed in 2026 in Canada?
In Canada, installed roof underlayment runs C$0.42 per sq ft for 15-lb asphalt-saturated felt, C$0.58 per sq ft for 30-lb felt, C$0.90 per sq ft for synthetic UDL (Titanium UDL-50, RoofTopGuard II, GAF Tiger Paw), and C$2.40 per sq ft for full self-adhered SBS. A 2,000 sq ft re-roof in Toronto, Calgary or Vancouver with synthetic underlayment, 200 lf of NBC-mandatory ice-and-water shield at the eaves and valleys, and 200 lf of drip edge, including tear-off and disposal, totals roughly C$4,000 to C$5,200 in 2026 CRCA member pricing. Source: Canadian Roofing Contractors Association Cost Survey 2026; HomeStars and Renomii Q1 2026 indicative rates.
Felt vs synthetic underlayment in Canada — which is better?
Synthetic UDL outperforms 15-lb and 30-lb felt on every measurable dimension except sticker price. Synthetic weighs roughly a quarter of 30-lb felt, tears at 50 to 100 lbf compared to 8 to 18 lbf for felt, has UV exposure ratings of 90 to 180 days vs 30 days for felt, lays flat without buckling and wrinkling from humidity (a critical factor in damp Vancouver Island and Maritime climates), and walks far safer in wet conditions. The cost gap is real — roughly C$0.32 per sq ft material premium — but on a 2,000 sq ft roof that is C$640 against a 25-to-50-year shingle warranty. IKO, BP and Malarkey now require synthetic underlayment for their full system warranty tiers.
Where does the National Building Code require ice-and-water shield?
NBC 9.26.6 requires self-adhered ice-and-water shield (Grace Ice & Water Shield, IKO ArmourGard, BP NailGuard) at all roof eaves where the average January temperature is -2.5°C or lower — basically all of Canada except coastal Vancouver Island and the southwestern Lower Mainland. The shield must extend from the eave edge to a point at least 900 mm past the inside face of the exterior wall (typically 1,200 mm up the roof from the fascia for a 2x6 wall and 6/12 pitch), or to a point higher than the highest expected ice-dam line. Best practice is to also strip in valleys (a 900 mm strip down each valley centerline), around chimneys, plumbing stacks and skylights. Cost is roughly C$2.10 per linear foot installed in 2026 CRCA pricing.
Do I need full self-adhered SBS under the whole roof?
Almost never on a sloped asphalt-shingle roof in Canada. Full self-adhered SBS costs C$2.30 to C$2.90 per sq ft installed and is overkill for a typical residential pitch. It is justified in three situations: (1) low-slope sections (2/12 to 4/12) where shingles alone do not meet NBC 9.26.5, (2) Atlantic provinces and Newfoundland houses in Category 1 wind zones where wind-driven rain risk is extreme, and (3) under metal roofing on board sheathing where condensation drainage matters. For everyone else, synthetic UDL on the field plus self-adhered ice-and-water shield at eaves and valleys is the right spec for any Canadian climate zone.
How much underlayment do I need for my roof?
Underlayment is sold in 'squares' — one square covers 100 sq ft. Felt rolls are typically 4 squares (400 sq ft) per roll. Synthetic rolls are commonly 10 squares (1,000 sq ft) per roll. Always add 10% to 15% for laps, cuts, and waste — manufacturers specify a minimum 50 mm horizontal lap and 150 mm vertical lap. For a 2,000 sq ft roof, plan on 22 to 23 squares of synthetic underlayment, plus 2 to 3 rolls of 900-mm-wide ice-and-water shield for eaves and valleys.
Can I install new underlayment over old?
NBC 9.26.18 allows it only if the existing underlayment is dry, intact, well-adhered, and the total roof covering does not exceed two layers. In practice, most CRCA-member roofers tear off old felt with the shingles for three reasons: (1) old felt is brittle and tears when shingles are removed, (2) inspection of the deck for rot and fastener pull-through is impossible without tear-off (especially important in freeze-thaw climates), and (3) most shingle manufacturer warranties (IKO Cambridge, BP Vangard, Malarkey Legacy) require fresh underlayment over a clean deck. Tear-off costs roughly C$0.52 per sq ft in 2026, including dump fees.
Does synthetic underlayment qualify for shingle warranty system upgrades?
Yes. IKO Performance Iron Clad Plus warranty accepts IKO StormShield and IKO RoofGard-Cool Grey. BP Lifetime warranty accepts BP NailGuard and BP RoofShield Plus. Malarkey EcoSeal warranty accepts Malarkey Right-Start UDL. To qualify for the upgraded warranty (typically lifetime material plus 25 years labour), you must use the manufacturer's branded underlayment, the manufacturer's branded ice-and-water shield, the manufacturer's starter strip, and the manufacturer's hip-and-ridge — installed by a CRCA-certified or manufacturer-certified contractor.
What is starter strip and is it the same as underlayment?
No, they are different products. Underlayment is a roll-good water barrier installed across the entire deck. Starter strip is a 7-to-9-inch peel-and-stick or nail-down strip applied along the eave edge before the first course of shingles, providing the sealant bond that anchors the leading edge against wind uplift. IKO Easy Glas, BP Vangard Starter Strip and Malarkey Right-Start all run roughly C$1.85 per linear foot installed in 2026.

Related calculators