Asphalt Underlayment
Last updated: 2026-10-07
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Asphalt Underlayment
Asphalt underlayment typically costs $0.80–$2.50 per square meter for standard roofing felts and $3.50–$9.00 per square meter for self-adhered SBS-modified membranes, with a standard 1,000 m² roofing project requiring 8–12 tonnes of material and 2–4 days of installation labor. In bitumen export terms, a single 40ft container holds roughly 24–26 tonnes of underlayment rolls, and bulk orders above 20 tonnes usually unlock a 5–12% price reduction versus spot purchases. The product itself is a bitumen-saturated or bitumen-coated sheet — felt, fiberglass, or polyester mat — installed beneath the primary roofing layer to block moisture, vapor, and wind-driven rain.
This guide breaks down asphalt underlayment types, pricing, technical specifications, and sourcing logistics for contractors, distributors, and roofing manufacturers working in export markets.
What Is Asphalt Underlayment?
Asphalt underlayment is a bitumen-based sheet material installed between the roof deck and the finished roofing surface (shingles, tiles, or metal panels). It functions as a secondary water barrier, a vapor retarder, and a wind uplift membrane.
Three core constructions dominate the market:
| Type | Reinforcement | Bitumen Content | Typical Weight | Price (USD/m²) |
|---|---|---|---|---|
| No. 15 organic felt | Organic felt | Saturant + coating | 0.55–0.65 kg/m² | $0.80–$1.40 |
| No. 30 organic felt | Organic felt | Saturant + coating | 1.10–1.30 kg/m² | $1.50–$2.50 |
| Fiberglass felt | Fiberglass mat | Coated | 0.45–0.70 kg/m² | $1.00–$1.80 |
| SBS self-adhered | Polyester/fiberglass | Modified, both sides | 1.80–3.20 kg/m² | $3.50–$9.00 |
| APP torch-down | Polyester | Modified | 3.00–4.50 kg/m² | $4.50–$8.50 |
Key material facts:
- Bitumen content ranges from 35% to 60% of total sheet weight, depending on grade.
- Standard roll dimensions: 1 m × 15 m (15 m²) or 1 m × 20 m (20 m²).
- Surface finishes include sand, talc, PE film, or mineral granule, each suited to a different climate.
- Service temperature range for SBS grades: −25°C to +100°C; APP grades: −10°C to +120°C.
The distinction matters commercially: organic felt remains the cheapest option and dominates price-sensitive markets in Africa, South Asia, and the Middle East, while SBS self-adhered membranes now account for roughly 40% of the US and EU residential underlayment market due to stricter building codes.
Price Comparison by Type and Region
Pricing depends on bitumen content, reinforcement, order volume, and FOB versus CIF terms. The table below reflects FOB China / FOB Middle East benchmarks for 2024–2025.
| Product | Min. Order (tonnes) | FOB Price ($/tonne) | CIF Europe ($/tonne) | CIF Africa ($/tonne) |
|---|---|---|---|---|
| No. 15 organic felt | 20 | $520–$680 | $780–$950 | $700–$880 |
| No. 30 organic felt | 20 | $700–$900 | $980–$1,180 | $900–$1,100 |
| Fiberglass felt | 20 | $600–$820 | $850–$1,050 | $780–$980 |
| SBS self-adhered | 15 | $1,400–$1,900 | $1,750–$2,350 | $1,650–$2,200 |
| APP torch-down | 15 | $1,200–$1,700 | $1,550–$2,100 | $1,450–$1,950 |
Notes on pricing:
- Organic felt (No. 15) pricing moved ±9% in the past 18 months, tracking oxidized bitumen at $430–$560/tonne.
- SBS membranes carry a 2.3–2.8× premium over organic felt but reduce installation labor by 15–25% because they are self-sealing.
- Orders above 100 tonnes typically receive an additional 6–10% discount.
- Payment terms of 30% deposit / 70% against B/L copy are standard for first-time export buyers.
Technical Specifications and Performance Data
Specifications follow ASTM D226 (organic felt), ASTM D4869 (fiberglass), and ASTM D1970 (self-adhered). Export buyers should always request a Certificate of Analysis (COA) with each shipment.
| Parameter | No. 15 Felt | No. 30 Felt | SBS Self-Adhered |
|---|---|---|---|
| Tensile strength (MD), N/50mm | ≥ 220 | ≥ 300 | ≥ 400 |
| Tear resistance, N | ≥ 15 | ≥ 25 | ≥ 30 |
| Water vapor permeance, perms | 0.5–2.0 | 0.5–1.5 | 0.05–0.10 |
| Low-temp flexibility | +5°C | +5°C | −25°C |
| UV exposure limit | 30 days | 30 days | 90–180 days |
| Fire rating (ASTM E108) | Class C | Class C | Class A (with cap sheet) |
Practical performance benchmarks from field data:
- Underlayment installed correctly reduces ice-dam leak claims by 60–75% in cold climates.
- Self-adhered SBS membranes improve wind uplift resistance by 25–40% versus mechanically fastened felt.
- Correct overlap — 100 mm side laps, 150 mm end laps — prevents over 80% of reported water intrusion failures.
- Underlayment lifespan: 15–25 years for felts under a primary roof; 25–35 years for SBS under ventilated assemblies.
Installation, Labor, and Logistics
Installation speed and labor cost are the two largest variables in project budgets after material cost.
| Task | Rate | Crew Size | Time per 100 m² |
|---|---|---|---|
| Organic felt (mechanically fastened) | 25–40 m²/hr | 2–3 | 3–4 hrs |
| Fiberglass felt | 30–45 m²/hr | 2–3 | 2.5–3.5 hrs |
| SBS self-adhered | 20–35 m²/hr | 2–3 | 3–5 hrs |
| APP torch-down | 15–25 m²/hr | 2–4 | 4–6 hrs |
Logistics data for export buyers:
- 40ft container capacity: 24–26 tonnes of rolled underlayment (palletized) or 28–30 tonnes floor-loaded.
- 20ft container capacity: 10–12 tonnes palletized.
- Standard roll packaging: poly-wrapped, 4–6 rolls per pallet, stretch film, edge protection.
- Loading time at factory: 6–10 hours for a full 40ft container; port-to-port transit: 18–35 days depending on route.
- Typical lead time from PO to vessel departure: 12–20 days.
Cost-per-square-meter, all-in (material + installation):
| Type | Material | Labor | Total |
|---|---|---|---|
| No. 15 felt | $1.10 | $0.90 | $2.00 |
| No. 30 felt | $2.00 | $0.90 | $2.90 |
| SBS self-adhered | $5.50 | $1.60 | $7.10 |
| APP torch-down | $6.20 | $2.30 | $8.50 |
For a 1,000 m² roof, this translates to $2,000–$8,500 in total underlayment cost — roughly 8–14% of the total roofing budget.
How to Choose and Source Asphalt Underlayment
Selection should be driven by climate, roof pitch, and code requirements, not price alone.
Decision checklist:
- Cold climates (−20°C or below): SBS self-adhered. Felt becomes brittle and cracks.
- Hot climates (40°C+, high UV): APP torch-down or granulated SBS; avoid unsurfaced PE film.
- Steep-slope roofs (>4:12): any type, but mechanical fastening is mandatory below 2:12.
- Budget projects, mild climate: No. 15 or No. 30 organic felt remains the lowest-cost compliant option.
- Code-driven markets (US, EU, Canada): ASTM D1970-compliant self-adhered membranes are now required in many jurisdictions.
Sourcing rules for importers:
- Always verify bitumen content by weight, not just nominal grade — some suppliers reduce coating to cut costs.
- Request 3rd-party lab test reports (SGS, Intertek, BV) before vessel booking.
- Confirm roll width tolerance (±1%) and length accuracy (±0.5%) — short rolls are a common hidden price increase.
- Insist on pallet weight and container loading plan to avoid overweight penalties.
- Lock payment terms and inspection clause in the contract; 30/70 T/T or L/C at sight are standard.
Typical order economics (40ft container, No. 30 felt):
- Volume: 25 tonnes ≈ 19,200 m² (at 1.3 kg/m²)
- FOB cost: $20,000–$22,500
- Freight + insurance: $3,500–$6,000
- Landed cost per m²: $1.25–$1.50
That landed cost is 15–22% below typical domestic distributor pricing in most import markets — the core reason export-sourced underlayment continues to gain share.
FAQ: Asphalt Underlayment
What is the price of asphalt underlayment per square meter?
Asphalt underlayment ranges from $0.80 to $2.50 per m² for organic and fiberglass felts, and $3.50 to $9.00 per m² for SBS self-adhered or APP torch-down membranes. Bulk export orders of 20 tonnes or more typically reduce unit pricing by 5–12%.
How many tonnes of asphalt underlayment fit in a 40ft container?
A standard 40ft container holds 24–26 tonnes of palletized underlayment rolls, or up to 28–30 tonnes if floor-loaded. This equals roughly 18,000–20,000 m² of No. 30 felt at a weight of 1.3 kg/m².
What is the difference between No. 15 and No. 30 asphalt felt?
No. 15 felt weighs 0.55–0.65 kg/m² and costs $0.80–$1.40/m², while No. 30 felt weighs 1.10–1.30 kg/m² and costs $1.50–$2.50/m². No. 30 offers roughly double the tensile strength and is preferred for steeper roofs and colder climates.
How long does asphalt underlayment last?
Under a finished roof, organic felt underlayment lasts 15–25 years, while SBS self-adhered membranes last 25–35 years. Prolonged UV exposure degrades all types within 30–90 days, so the primary roof covering must be installed promptly.
Is self-adhered SBS underlayment worth the higher price?
Yes, in cold or high-wind regions. SBS membranes cost 2.3–2.8× more than felt but reduce leak claims by 60–75% and improve wind uplift resistance by 25–40%, often offsetting the premium within the first maintenance cycle.
Calculate Your Asphalt Underlayment Cost Instantly
Before you place your next underlayment order, run the numbers with the 6Tar cost calculator — it breaks down FOB price, freight, insurance, duties, and landed cost per tonne and per m² in seconds. Whether you are importing 20 tonnes of No. 30 felt or 25 tonnes of SBS self-adhered membrane, the calculator shows your true cost before you commit. Try 6Tar now and turn raw quotes into a clear, comparable landed-cost figure.