What is Kompriband?
Kompriband (also known as joint sealing tape or pre-compressed sealing tape) is an impregnated foam tape that is pre-compressed and wound onto a roll. After installation, it slowly expands and reliably seals joints between windows, doors, and masonry – against wind, driving rain, dust, noise, and heat loss.
Kompriband is an essential sealing material in modern window construction and is used by both professional craftsmen and in DIY projects.
Frequently Asked Questions about Kompriband
What do BG1 and BG2 mean according to DIN 18542?
- BG1 – the highest requirement level, for joints directly exposed to weather (exterior windows, facade connections, exposed locations).
- BG2 – for joints not directly exposed to weather (covered areas, interior areas, protected connections).
Conclusion: Always use BG1 for exterior windows. BG2 only for protected areas.
What joint width do I need?
The specification on the packaging (e.g., "10–20 mm") indicates the joint range. Measure the joint at its narrowest and widest points and choose a tape that covers both values.
Example: Joint 8–14 mm → tape with a joint range of 8–15 mm or 10–20 mm.
What cutting width do I need?
The cutting width corresponds to the joint width (depth). It should be at least half the joint width, ideally equal to or slightly larger than the joint width.
Kompriband vs. Joint Sealing Tape – what's the difference?
Both terms refer to the same product. Not to be confused with: butyl tape (does not expand), window connection tape (FAB) (foil-based), or silicone/acrylic (pasty sealants).
How is Kompriband installed correctly?
- Prepare the substrate: clean, dry, grease-free.
- Cut the tape to length – with a sharp knife, do not tear.
- Remove the protective film – only just before installation.
- Adhere the tape – evenly, without stretching.
- Allow to expand – do not stress during expansion.
- Overlap joints – at least 5 mm.
Important: Always install compressed – never push into an already open joint.
Is Kompriband waterproof?
Kompriband is driving rain-proof and permanently weather-resistant, but not permanently waterproof under water (e.g., with standing water or pressurized water). It effectively protects joints from penetrating rainwater and wind, but at the same time allows water vapor from inside the building structure to escape to the outside – to prevent mold formation.
Can I install windows without Kompriband?
Yes, technically it is possible, but not permissible according to building regulations (RAL installation / DIN 4108-7). Without Kompriband or an equivalent sealing foil, the driving rain protection outside and the necessary airtightness are missing. If you rely only on building foam, moisture will eventually get into the joint – leading to insulation losses and mold damage.
Is a Kompriband tight?
Yes, provided it has been selected for the correct joint area. A Kompriband reliably seals against air, wind, drafts, and driving rain. Depending on the design (e.g., multifunction sealing tapes / BG1 tapes), it meets various requirements for driving rain resistance (often up to 600 Pa) and airtightness.
Can Kompriband be plastered over?
No, conventional Kompriband should not be plastered over directly. The plaster adheres poorly to the compressed foam, and due to the constant movements of the building component, cracks quickly appear in the plaster. If you want to plaster over the joint directly, you should use special plasterable window connection foils or plaster connection profiles (APU profiles).
What colors are available?
Most common: black and gray. The color has no influence on the technical properties.
How long does Kompriband last?
High-quality Kompriband according to DIN 18542 BG1 is designed for at least 10 years – with correct installation and a suitable substrate.
Can Kompriband be installed in winter?
Yes, but not below +5 °C. If it's cold, store the tape at room temperature for at least 24 hours.
How much does Kompriband cost?
- Without standard certification: from approx. €0.50–1.00 per meter
- BG2 certified: approx. €0.50–3.00 per meter
- BG1 certified: approx. €0.60–8.00 per meter
How much Kompriband do I need?
Measure the total joint circumference + 10% for waste. Example: 5 windows × 5 m = 25 m + 10% = approx. 28 m.
Can Kompriband be painted over?
Yes – after full expansion (30 minutes to several hours). Check compatibility with paint beforehand.
Single-sided vs. double-sided self-adhesive?
- Single-sided SA: Standard for most applications.
- Double-sided SA (full surface): Not known
Buying Kompriband – what to look for?
- ✅ DIN 18542 BG1 for exterior joints directly exposed to weather
- ✅ DIN 18542 BG2 for protected areas
- ✅ Suitable joint range and cutting width
- ✅ Sufficient roll length
- ✅ Processing temperature at least +5 °C
