The Sealmaster GTR Intumescent Foam Glazing Tape is a flexible, highly compressible fire-rated glazing tape developed for use around fire-resistant glass in timber fire doors and glazed fire screens.
Unlike conventional foam glazing tapes, GTR incorporates intumescent technology. Under fire conditions, the material begins to expand at approximately 180°C, increasing to around 3–4 times its original volume and forming a stable char to help maintain the integrity of the fire-resistant glazing system. The material has also been developed to resist thermal erosion at temperatures exceeding 900°C.
The tape combines this high-temperature performance with the practical benefits of a soft, flexible glazing tape. A strong self-adhesive backing allows it to be quickly applied to glazing beads and around apertures, while the compressible foam accommodates the interface between the glass and glazing bead. It can easily be cut to size using scissors or a sharp knife, making installation straightforward even around accurately detailed glazing apertures.
Sealmaster GTR is suitable for use within a broad range of fire-resistant glazing systems, including integrity, semi-insulating and insulating glass applications, subject to the requirements and evidence applicable to the complete glazing system.
Key Features & Benefits
- Intumescent fire glazing tape for fire-resistant glass
- Suitable for timber fire doors and glazed fire screens
- Designed particularly for 30- and 60-minute fire-resisting applications
- Flexible and highly compressible foam construction
- Low-to-medium pressure intumescent action
- Expands to approximately 3–4 times its original volume
- Intumescent expansion begins at approximately 180°C
- High resistance to thermal erosion, with char stability beyond 900°C
- Strong self-adhesive backing for rapid installation
- Easy to cut and accurately fit around glazing beads
- Can compress from 5 mm to approximately 2 mm
- Available in several widths for different glazing arrangements
- CERTIFIRE approved under Certificate CF5387, subject to the certified glazing system requirements
Fire Performance & CERTIFIRE Approval
The Sealmaster Intumescent Foam Glazing Tape is covered by CERTIFIRE Certificate CF5387, which was reissued in May 2026 and is currently valid until 13 May 2031. The certification relates to the tape's contribution to the fire resistance of specified timber door leaves and timber glazed screens for 30- and 60-minute integrity, including insulation where applicable, in accordance with the conditions of the certificate.
The certified glazing arrangement includes more than the tape itself. Depending on the application, the complete system incorporates the approved fire-resistant glass, glazing beads, retaining method, aperture lining where required, and a suitable fire-resistant timber doorset or glazed-screen construction.
Fire performance should therefore always be considered as the performance of the complete tested or assessed glazing system, rather than of the glazing tape in isolation.
Suitable Applications
Sealmaster GTR Intumescent Foam Glazing Tape is suitable for use in specified fire-resistant glazing applications including:
- Glazed apertures within FD30 timber fire doors
- Glazed apertures within FD60 timber fire doors
- Fire-resistant timber glazed screens
- Fire door vision panels
- Fire-resistant glass and timber glazing bead systems
- Commercial and public buildings
- Schools and educational buildings
- Healthcare facilities
- Hotels and residential developments
- Offices and commercial developments
The exact glazing configuration, glass type, aperture size, bead specification and fixing arrangement should comply with the appropriate fire test, assessment or CERTIFIRE approval for the particular doorset or screen.
Sizes
Sealmaster GTR is supplied in 20 metre rolls in the following standard sizes:
10 mm × 5 mm × 20 m
15 mm × 5 mm × 20 m
20 mm × 5 mm × 20 m
Other widths may be available from the manufacturer on request. The nominal 5 mm thickness can be compressed to approximately 2 mm where required by the glazing arrangement.
Technical Information
Product: GTR Intumescent Foam Glazing Tape
Manufacturer: Sealmaster
Product Type: Intumescent fire glazing tape
Colour: Black
Roll Length: 20 metres
Standard Widths: 10 mm, 15 mm and 20 mm
Thickness: 5 mm
Compressed Thickness: Approximately 2 mm
Expansion: Approximately 3–4 times original volume
Expansion Begins: Approximately 180°C
High-Temperature Stability: Char stability beyond 900°C
Fixing: Self-adhesive
Certification: CERTIFIRE CF5387
Primary Applications: Fire-resistant glazing in timber fire doors and glazed timber screens
Easy Installation
The GTR Intumescent Foam Glazing Tape incorporates a strong adhesive backing, allowing it to be applied directly to the glazing bead or other appropriate surface within the approved fire glazing system.
Its flexible foam construction makes the tape easy to handle and allows it to be cut accurately with scissors or a sharp knife. This is particularly beneficial when working around fire door vision panels and other glazing applications where accurate positioning is required.
Installation must follow the requirements of the relevant fire doorset, glazing system and current Sealmaster/CERTIFIRE documentation.
Why Choose Sealmaster GTR Intumescent Glazing Tape?
Fire-resistant glazing requires more than simply installing fire-rated glass. The glass, glazing beads, fixings, aperture construction and glazing seals must work together as an appropriately tested or assessed system.
The Sealmaster GTR Intumescent Foam Glazing Tape combines the convenience and compressibility of a conventional foam glazing tape with the additional protection of a low-pressure intumescent material. Its combination of easy installation, strong adhesive backing and certified fire-glazing applications makes it particularly suitable for professional fire door manufacturing, maintenance and fire-resistant glazing installations.
