Fleece Airtight Tape
Airtight fleece tape for eco and airtight projects
airtight window tape for passivhaus projects - IM FLEECE TAPE
airtight window tape IM fleece tape for window sealing
IM fleece tape airtight tape for passivhaus builds

Airtight Tape

Enquire Now BelowFrom £40.00 + VAT

75mm, 100mm, 150mm & 200mm widths available

Premium Airtight Window & Joint Sealing Tape

Our high-performance airtight tape is engineered for windows, doors, and connecting joints, providing exceptional air and weather sealing. Designed for both interior and exterior applications, this professional-grade tape features a durable polyamide film bonded with a non-woven fleece surface and a 20mm cornering flange for perfect joint coverage.

With its four-layer variable sd-value structure, this tape delivers superior flexibility and performance across a wide range of building types, from new builds to retrofit projects. The aggressive full-surface adhesive backing ensures quick, hassle-free installation and a completely hidden finish, allowing it to be plastered or painted over without any risk of adhesive bleed-through.

For added versatility, an optional top-surface self-adhesive strip is available, making it easier to achieve perfect positioning during installation.

Key Benefits:

  • Ultimate airtightness and weather protection for windows and joints

  • Variable sd-value for moisture control and long-lasting durability

  • Hidden installation – can be plastered and painted over

  • Quick, self-adhesive application for time-saving performance

  • Suitable for Passivhaus, energy-efficient, and retrofit projects

This 25m airtight tape is available in 4 width sizes:

75mm airtight tape from £40.00
100mm airtight tape from £50.00
150mm airtight tape from £75.00
200mm airtight tape from £100.00

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What Is Intelligent Membrane Fleece Tape?
  • Key Details
    • Moisture-dependent SD value
    • Suitable for retrofit and new construction
    • High adhesive strength of the mounting strip on all kinds of window frames and different types of masonry base
    • Can be installed at low temperatures and can be plastered / painted over
    • Stretchable
    • Temperature resistance -40°C to +80°C
    • Shelf life 24 months, dry at room temperature and in the original packaging
    • Weight – approx. 350 g/m²
    • Thickness – approx. 0.55 mm
    • Fire performance – Class E, MPA*
    • UV stability 12 months, MPA
    • View our technical data sheet for more details
  • Description

    Airtight Tape – High-Performance Airtight Sealing Solution

    Our Airtight Tape is a premium, fleece-backed sealing tape designed to deliver long-lasting airtightness and vapour control across a wide range of construction details. Flexible, durable, and easy to install, it ensures a reliable seal on even the most challenging junctions and penetrations.

    Perfect for both new-builds and retrofit projects, Airtight Tape bonds strongly to common building substrates such as timber, concrete, brick, and membranes. Its reinforced fleece surface allows for excellent plaster or paint adhesion, making it ideal for invisible integration into the building fabric.

    By eliminating air leakage at key junctions, Airtight Tape helps improve energy efficiency, comfort, and building durability, making it an essential component for airtight construction and Passivhaus-standard projects.

    Key Benefits:

    • ✅ Strong adhesion – bonds to timber, brick, concrete, and membranes

    • ✅ Fleece-backed – can be plastered or painted over seamlessly

    • ✅ Flexible & durable – ideal for corners, joints, and penetrations

    • ✅ Weather resistant – suitable for long-term performance

    • ✅ Energy saving – supports airtightness targets for low-energy and Passivhaus builds

    Airtight Tape is the simple, effective, and professional choice for creating a continuous airtight layer in your building envelope.

    Additional information

    Choose Option

    75mm x 25m (Single Roll), 75mm x 25m (Box of 5), 100mm x 25m (Single Roll), 100mm x 25m (Box of 4), 150mm x 25m (Single Roll), 150mm x 25m (Box of 2), 200mm x 25m (Single Roll), 200mm x 25m (Box of 2)
  • Data Sheets & Certificates
    Technical Data Sheet
    Install Guide
    Safety Data Sheet
  • Architects Specification

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  • Delivery

    All delivery charges are included in the price of the products and are dependent on the products selected for purchase. This charge is based on delivery to mainland UK, excluding the Scottish Highlands & the Islands where additional shipping charges will apply. For more information read our delivery policy in full.

    Intelligent Membranes do not offer a next day delivery service.

    Intelligent Membranes aim for deliveries to be with the customer within 2 working days. During the festive period deliveries could take longer.

    Orders placed before 12pm will be dispatched the same day, any orders placed after 12pm will be dispatched the following working day

  • Returns

    We, at Intelligent Membranes, would like you to be 100% satisfied with your purchase and our service. In the unfortunate event of any item being unsuitable or wrong, please read our returns policy in full.

IM Fleece Airtight Tape – Frequently Asked Questions

1. What is IM Fleece Airtight Tape used for?

IM Fleece Airtight Tape is designed to seal window and door junctions, masonry-to-frame connections, and service penetrations, ensuring a continuous airtight layer in both new build and retrofit projects.

2. Is IM Fleece Airtight Tape breathable?

Yes. The fleece backing allows for vapour diffusion, ensuring walls remain breathable while still achieving airtightness.

3. Can it be plastered or painted over?

Yes. Once installed, the fleece surface can be plastered, skimmed, or painted over, making it ideal for invisible airtightness detailing.

4. How do I install IM Fleece Airtight Tape?

The tape is self-adhesive for fast application. Simply:

  1. Cut to length

  2. Apply to the frame or junction

  3. Press firmly into place

  4. Plaster or paint over the fleece face for a seamless airtight finish

5. Can IM Fleece Tape be used externally?

Yes. It can be used both internally and externally, depending on project requirements. For external applications, it provides weather resistance while maintaining vapour openness.

6. Does IM Fleece Airtight Tape stick to rough surfaces?

Yes. Thanks to its high-tack adhesive, it bonds well to masonry, blockwork, timber, and concrete, even on slightly uneven substrates.

7. Do I need a primer?

On dusty or very porous substrates, we recommend using IM Primer before applying the tape to ensure maximum adhesion.

8. How long does the adhesive last?

IM Fleece Airtight Tape is designed for permanent adhesion and forms part of the building’s long-term airtightness strategy, helping to meet Passivhaus airtightness standards.

9. Is it compatible with Passive Purple?

Yes. IM Fleece Tape works perfectly with Passive Purple liquid membranes. Use the tape for junction detailing and Passive Purple to achieve a continuous airtight seal across the wider building fabric.

10. How does it help with air testing?

By sealing critical junctions and penetrations, IM Fleece Airtight Tape reduces air leakage, making it far easier to achieve low air change rates (ACH) and pass airtightness testing

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