Discover reliable bonding for pitched roof underlayment. TECHNOMELT® hotmelt adhesives enable fast processing, clean application, and long-term durability.
Reliable bonding solutions for modern roof systems
Underlayments are the unsung heroes of pitched roofs. They form the critical protective layer beneath tiles or shingles—shielding buildings from wind, moisture, and vapor intrusion. For these membranes to perform reliably over years of exposure, their bonding and lamination must be equally durable.
That’s where TECHNOMELT® hotmelts make a decisive difference.
Our pressure-sensitive (PSA) and polyurethane reactive (PUR) hotmelt adhesives are engineered for bonding and laminating roof underlayment, including breathable roof membranes. They deliver secure adhesion, long-term durability, and high production efficiency across diverse substrates and process conditions.
Whether you manufacture vapor barriers, breathable roof underlayments, or multi-layer laminates, TECHNOMELT® delivers consistent performance across diverse substrates and process conditions.
Roof underlayment faces extreme conditions—from sub-zero winters to scorching summer heat beneath dark roof tiles. Adhesives used in these systems must maintain adhesion and elasticity despite:
- Thermal expansion and contraction
- UV exposure (indirectly through tiles)
- Humidity and vapor transmission
- Mechanical stress during installation and wind uplift
Traditional solvent-based or water-based systems often struggle with such conditions, leading to edge lifting, delamination, or adhesive migration over time.
Hotmelt adhesives, on the other hand, form immediate bonds, provide excellent temperature stability, and integrate seamlessly into high-speed roofing membrane underlayment production.
TECHNOMELT® is Henkel’s global brand for hotmelt adhesives designed for demanding industrial applications. In roofing, the TECHNOMELT® portfolio offers formulations that combine:
- Excellent adhesion to polyolefins, PET, PA, and aluminum
- High temperature resistance
- Cold flexibility
- Fast processing
- Clean application
- Long open time (for PSA)
Together, these properties ensure long-term weatherproofing reliability and production efficiency — two critical success factors for underlayment manufacturers.
What are roof underlayments?
Roof underlayments (also called roof membranes or vapor barriers) are multi-layer films installed beneath roof coverings such as clay tiles, metal sheets, or shingles. They serve to:
- Block water ingress during heavy rain or snow
- Allow moisture vapor to escape from within the roof structure
- Improve wind and thermal resistance
A typical underlayment structure may include:
- Top layer: UV-stabilized nonwoven or film (e.g., PP or PE)
- Functional layer: Breathable or vapor-tight film
- Bottom layer: Nonwoven or adhesive surface for fixation
Each interface requires precise bonding — which is where TECHNOMELT® adhesives deliver tailored performance.
TECHNOMELT® PS 203A — Pressure-Sensitive Hotmelt for Flexible Bonding
TECHNOMELT® PS 203A is a pressure-sensitive hotmelt adhesive (PSA) designed for applications requiring immediate tack, long open time, and excellent thermal stability.
It is ideal for bead or stripe application on vapor barriers and roof underlayment, and is compatible with breathable roof membranes used on pitched roofs.
The adhesive remains slightly tacky after application, allowing strong yet flexible bonds that can absorb movement in the roofing structure. It’s particularly suited for:
- Edge sealing of vapor barriers
- Overlap bonding in multilayer laminates
- Fixation of reinforcement strips
The result: durable adhesion without cold-flow or residue formation, even under cyclic thermal load.
For high-end roof underlayments requiring structural bonding and superior environmental resistance, TECHNOMELT® PUR 141 is the recommended solution.
It’s a moisture-curing polyurethane hotmelt, forming strong, elastic, and heat-resistant bonds after crosslinking.
PUR hotmelts like TECHNOMELT® PUR 141 are preferred for industrial lamination lines, where high production speeds and permanent adhesion are critical.
The thermoplastic phase allows immediate handling after cooling, while chemical curing ensures long-term resistance to heat, moisture, and mechanical stress common in roof underlayments.
Henkel’s sustainability mission is deeply embedded in the TECHNOMELT® portfolio. Hotmelt adhesives for roof underlayments offer:
- Solvent-free formulation (zero VOC emissions)
- Reduced energy consumption through low-temperature processing
- Precise dosing with minimal waste
- Longer equipment life thanks to low char formation
Additionally, Henkel is developing bio-based and carbon-optimized variants to help roofing manufacturers achieve their environmental goals without compromising performance.
Every TECHNOMELT® product is produced under Henkel’s ISO-certified quality and environmental systems. Each adhesive grade undergoes stringent batch control, including:
- Viscosity and thermal stability testing
- Color and contamination checks
- Bond strength and peel adhesion evaluation
Henkel’s Application Engineering teams support customers globally with:
- Process optimization
- On-site testing and pilot trials
- Equipment calibration
- Training for production staff
Get in touch with Henkel’s experts and start exploring advanced materials solutions today.
Our support center and experts are ready to help you find solutions for your business needs.