Roof underlayment and housewrap

we supply high-performance synthetic roofing underlayment that protects those roof decks for moisture and offers maximum traction to roofing crews. we are one of the best synthetic roofing underlayment suppliers from China. Meanwhile, we also can provide synthetic house wrap for our contractors.

Our synthetic factory is OEM for some of famous North America roofing underlayment and house wrap brand, so the quality is guaranteed. When buying from us ,you will really understand that the competitive and low price doesn't mean yield to quality, because we have no middleman!

Our Advantage

Competitive Price, almost 30% off compared with buying from those third distributions

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Our biggest advantage: the most anti-skid Backside Coating and patterns, super high-performance and providing the best protection for your employees.

We can adjust the specifications of synthetic roof underlayment from 20 Lbs to 50 Lbs depend on clients requirement, besides, we provide service of printing customer logos on synthetics,What an impressive publicity, when others see your company logos on the roof.

Our biggest advantage: the most anti-skid Backside Coating and patterns, super high-performance and providing the best protection for your employees.

Synthetic underlayment features:

The general specification is 10 square and 24 Lbs per roll.
Meets or Exceeds Performance criteria for ASTM D226 Types I & II
Meets or Exceeds Performance criteria for ASTM D4869 Types I, II, III & IV
Fire Classification: Class A ASTM E108
extremely high tear strength
Impervious to mold Growth
Secondary Weather Protection Layer
90 Day UV Protection

Download: Shuangshi Products Brochure

1. Shuangshi Manufacturing Process of Synthetic Underlayment

Synthetic roof underlayment is an advanced alternative to traditional asphalt-saturated felt, offering superior durability, waterproofing, and ease of installation. Typically constructed in two to four layers, it combines woven or non-woven fabrics with polymer coatings, UV stabilizers, and slip-resistant additives to meet stringent performance standards.

1. Multi-Layer Structure and Material Composition

Synthetic underlayment is typically composed of two to four primary layers:

Base Layer (Carrier Material):
- Woven or Non-Woven Fabric: Polypropylene (PP) or polyester (PET) is commonly used due to its high tensile strength and tear resistance.
  - Woven fabrics provide enhanced dimensional stability.
  - Non-woven fabrics (spunbond or needle-punched) offer better flexibility and puncture resistance.
Waterproofing Layer (Lamination/Coating):
- A polyethylene (PE) or polypropylene film is extruded onto the base material via cast coating or lamination, ensuring complete waterproofing.
Additives for Performance Enhancement:
- UV Stabilizers – Protect against degradation from prolonged sun exposure.
- Slip-Resistant Agents – Silica particles or textured coatings improve traction during installation.
- Flame Retardants – Enhance fire resistance to meet building codes.

2. Surface Treatment: Embossing for Anti-Slip Properties

To ensure workers' safety and prevent slippage during roof installation, synthetic underlayment undergoes embossing (texturizing):

A patterned roller presses the surface, creating a raised texture, This increases friction without compromising waterproofing.

3. Importance of Grammage (Weight per Unit Area), always short for gsm.

The physical performance of synthetic underlayment is directly influenced by its grammage (g/m²). Higher-weight products exhibit:

Greater Tensile Strength – Resists stretching under tension.
Higher Tear Resistance – Prevents damage from foot traffic or wind uplift.
Improved Waterproofing – Thicker coatings enhance moisture barrier properties.

As a result, higher grammage underlayments are more expensive but offer superior durability and longevity, making them ideal for extreme weather conditions.

2. Synthetic Roof Underlayment Testing and Certification

Synthetic roof underlayment has become a popular alternative to traditional felt paper due to its superior durability, water resistance, and ease of installation. In North America, compliance with industry standards such as ICC-ES AC188, ASTM D8257/D8257M, and the Florida Building Code (FBC) is essential for ensuring product performance and safety. Additionally, third-party certifications like Intertek provide further validation of quality and reliability. This article explores the key testing methods, standards, and certification processes governing synthetic roof underlayment in the North American market.

1. ICC-ES AC188: Acceptance Criteria for Synthetic Roof Underlayments

The ICC Evaluation Service (ICC-ES) AC188 standard establishes the performance requirements for synthetic roof underlayments, ensuring they meet structural and weather-resistance benchmarks.

Key Testing Requirements:

Tensile Strength – Measures resistance to tearing under stress (ASTM D5034).
Puncture Resistance – Evaluates durability against sharp objects (ASTM D781).
Water Resistance – Assesses waterproofing capabilities (ASTM D779).
UV Resistance – Determines degradation under prolonged sun exposure (ASTM G154).
Dimensional Stability – Checks for shrinkage or expansion under temperature changes (ASTM D1204).

Manufacturers must submit test reports to ICC-ES for evaluation before receiving an Evaluation Service Report (ESR), which confirms compliance with building codes such as the International Building Code (IBC) and International Residential Code (IRC).

2. ASTM D8257/D8257M: Standard Specification for Synthetic Roof Underlayment

ASTM D8257/D8257M provides a comprehensive framework for evaluating synthetic underlayment performance.

Critical Test Methods:

Tear Strength (ASTM D226) – Ensures resistance to mechanical damage.
Water Absorption (ASTM D471) – Measures moisture retention.
Low-Temperature Flexibility (ASTM D2136) – Confirms performance in cold climates.
Fire Resistance (ASTM E108) – Evaluates flame spread and burning characteristics.

This standard is widely referenced in building codes and ensures underlayments can withstand harsh weather conditions while maintaining structural integrity1.

3. Florida Building Code (FBC) Requirements

Florida’s stringent building codes mandate additional testing due to extreme weather conditions (hurricanes, high humidity, and UV exposure).

FBC-Specific Tests:

High Wind Uplift Resistance (TAS-117) – Ensures underlayment stays secured in hurricane-force winds.
Impact Resistance (TAS-102) – Tests resistance to hail and debris.
Mold & Mildew Resistance (ASTM G21) – Prevents organic growth in humid climates.

Products must pass these tests to receive Florida Product Approval (FPA), a requirement for roofing materials in the state1.

4. Intertek Certification for Synthetic Underlayment

Intertek provides independent testing and certification, including:

ETL Listed Mark – Confirms compliance with safety and performance standards.
Code Compliance Evaluation Reports (CCERs) – Aligns with ICC-ES AC188 and ASTM D8257.
Hurricane & Windstorm Certification – Validates resistance to extreme weather.

Intertek’s testing ensures synthetic underlayments meet IBC, IRC, and regional building codes, enhancing market credibility

​Roof underlayment and housewrap