Hannoband 3E BG1 Your foolproof, all-in-one solution for sealing windows:
weather seal, vapour membrane and insulation

The top tape among the joint sealing tapes; Withstands driving rain to over 600 pascals


  • For heavy-duty primary and cross joints
  • All relevant test certificates are available
  • Resistant to long-term weathering
  • European Technical Approval ETA 06/0083
  • Corresponds to DIN 18542:2009, stress group 1
  • Building materials class B1 DIN 4102
  • Thermal conductivity λ=0,0429 W/mK
  • Resistant to driving rain ≥ 600 Pa
  • Joint sound insulation value RST,W max. 59 dB
  • Temperature stability from -30°C to +100°C, briefly to max. +130°C
  • Open to diffusion


  • In very warm weather the foam will expand more quickly giving less time for location of the window in the frame. If possible, keep the product cool

Hannoband BG1 is a traditional joint sealing tape that will pass all modern building specifications and will continue to perform year after year. It is best used with an internal flashing tape such as Hanno Duo Easy and a foam filler.

With window technology improving year on year to prevent heat loss and consequently keep energy bills down, Hannoband 3E ensures those gains don't go to waste on fitting.

It’s so good, it can be used in passive houses and wherever it’s used, it conforms perfectly to building brickwork for a clean finish, where you see the window, not the sealant.

6 benefits of Hannoband 3E BG1

  • 1 Weather tightness against wind-driven rain up to 1050 pascals
  • 2 Air tightness to prevent heat leakage through air movement via unique built-in membranes
  • 3 Impregnated foam insulation to reduce transmitted heat loss
  • 4 Best in class acoustic insulation
  • 5 Fire resistance
  • 6 A breathable seal so moisture can escape

The Hannoband 3E BG1, is probably one of the most underrated products in our whole portfolio. It's an expanding foam tape used to install windows. It forms a weather tight seal between the window frame and the building – and the very best product to do this job. It is the most effective, reliable and long-lasting solution and it is the best product from an environmental point of view, for saving precious energy. I'd like to tell you exactly why, but to put it into context, let's think for a minute about windows, particularly from the point of view of heat loss, or energy conservation.

The purpose of windows is to let light in and allow visibility to the outside, while keeping the wind and rain out. Before that, there was just a gap in the wall, which naturally had to be kept small. Glass was a brilliant invention because it allowed big windows and plenty of light. Unfortunately, glass is a very poor insulator against the cold outside. Some of us still remember waking up to find a layer of ice on the inside of the bedroom windows. But, windows have come on a long way since the early days. If you are looking to buy windows now you will know that modern windows are expensive. If you manufacture windows you know exactly why this is. Modern windows are designed and made to look good, so they actually enhance the look of the building, to keep all of the wind and rain out and, they require little or no maintenance for many years. Critically (at least in latitudes where we have cold winters) they enhance the energy performance of the building.

Over the years, governments and householders have become increasingly aware of the cost of wasted energy and the burden this puts on the environment as well as the householder's pocket..

The best performing windows have the following features:

  • The panes of glass are coated to reduce radiation the radiation of heat out, reflect heat back in and allow maximum solar gain (the free heat we can get from the sun)
  • The gap between the double-glazed panes is optimized and filled with inert gas instead of air
  • The spacers between the glass panes are themselves insulating
  • The frames have built-in insulation, maybe with heat breaks
  • The seal on the casement or sash is a sophisticated long-lasting seal that keeps it completely air-tight when closed

The best performing windows are highly developed and relatively expensive, although they will save money in the longer term and help protect the environment. YET... many of these expensive, sophisticated windows are still installed in the old fashioned way using beads of mastic around the outside. And that detracts from the performance (and look) of the window. WHY?

Mastic performs just one single function – it provides a weathertight seal. It stops wind and rain getting in between the window and the building. Even then, it may not perform this properly over time.

  • If the window or the building move, the mastic has very limited flexibility and may crack away from the building or the frame
  • If water does get behind the seal, the mastic will not allow it to escape, and it can build up
  • Mastic provides virtually no insulation – either from heat or sound
  • It doesn't even look good

Modern building standards look for three components in a window seal:

  • Weather tightness against wind driven rain
  • Air tightness to prevent heat leakage via air movement
  • Insulation to reduce transmitted heat loss
  • In addition, the seal should be breathable so moisture can escape

Hannoband 3E BG1 does all this and more and is a product that complements rather than detracts from the excellent look and performance of your new window. Unlike mastic, it performs a number of functions:

  • It is an effective weatherseal – resists driving rain up to 1050 pascals – best in class
  • The unique built-in membranes ensure air-tightness. This is a recent addition to building regulations, as air tightness is important in the building's overall insulation performance
  • The impregnated foam is an excellent insulator – not only against heat loss but also against noise transmission. The heat insulation is so good, 3E BG1 can even be used in passive houses. The acoustic insulation, because of the unique membranes, is also best in class.
  • The product is breathable, so water vapour can transmit out into the air
  • It requires no other products – it really is all-in-one solution
  • And it looks great. It provides a clean black line which is neat and unobtrusive. It conforms perfectly to the building brickwork so you see the window not the sealant. Here are a couple of photos from a job one of our customers recently completed. Firsly, you can see the white mastic around the old windows. Not very neat. And here is the new window with Hanno 3E, showing how well it conforms to the brickwork and how neat it looks.

More features:

  • For heavy-duty primary and cross joints
  • All relevant test certificates are available
  • Resistant to long-term weathering
  • European Technical Approval ETA 06/0083
  • Corresponds to DIN 18542:2009, stress group 1
  • Building materials class B1 DIN 4102
  • Thermal conductivity λ=0,0429 W/mK
  • Resistant to driving rain ≥ 600 Pa
  • Joint sound insulation value RST,W max. 59 dB
  • Temperature stability from -30°C to +100°C, briefly to max. +130°C
  • Open to diffusion






Frequently Asked Questions

What are your standard roll widths?

We slit most of our products to order, so we have no standard roll width. If you want 13mm or 133mm, you can have it.

What is the minimum and maximum roll width?

As a standard, the minimum is 6mm. We can slit most products narrower than this (we have slit down to 1.6mm) but we charge the same per roll as if it were 6mm, due to the increased slitting and packaging difficulty and the increased waste. The maximum width depends on the product, but is usually at least 1 metre.

Are the products held in stock?

We hold large quantities of bulk rolls in stock and manufacture to order. That's the only way we can offer the number of products and product variations that we do.

What is your delivery time?

UK deliveries on rolls, 3 to 5 working days. Spools, pads and die-cuts are 10 working days. If your order is urgent, please speak to our sales department and we'll try to help. Export orders are subject to longer delivery times.

How much do I have to order?

Our MOQ on most rolls is £100. On rolls of Techniflex and on other formats it is £200.

What are the delivery charges?

On UK orders over £200 delivery is free. On orders between £100 and £200 we add a small order charge of £20. We can arrange a.m. and courier deliveries for additional charges.

What is your returns policy?

As our products are made to order, we cannot generally accept returns unless the goods are faulty. 

What guarantees do you offer?

We are proud to guarantee the quality and performance of all our products and will quickly provide a replacement or refund if they fail to meet our standards.

Do you export, if so where?

Yes, we export around the world. Currently we export to Europe, the Far East, Australia and the US.