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The Isocell Team
Full building air and wind tight envelope system

Welcome to the information part of our website for the  Isocell Airstop range of tapes, membranes, adhesives and sealants. At Isocell Airstop, the external shell is the most crucial element of any structure. By building this right, you can achieve an energy-efficient, comfortable, and durable build. What's the point in bolting on renewables when the structure is not designed to maximize their benefits? Pound for pound, you will get a better return for your money by ensuring proper insulation, airtightness, and cold-bridge elimination. By building right and tight, you can offer your clients a better-built home and take advantage of the benefits of airtightness regarding your energy ratings.

Isocell Airstop is not just a product. It's the solution.


Isocell Airstop allows you to seal a structure by providing a range of products designed to achieve the desired result. Using alternative solutions not intended for airtightness can lead to short- to medium-term issues as they lose their effectiveness and sealing properties due to settlement and movement within the building and elements. Isocell Airstop products are designed and manufactured to cater for this, providing a guaranteed system that will stand the test of time.


We aim to make it easy to achieve high levels of airtightness in any build. Here you will find simple-to-follow instructions on confidently selecting, specifying and installing products from the comprehensive Airstop range to seal standard construction details.


While it isn't possible to describe every detail, we hope you will see that sometimes the key to getting a good seal is the creative use of the product. Our products are designed to offer flexibility while harmoniously integrating.  


About Our Product Range

All Isocell Airstop products, where standards exist, meet European Harmonised Standards and carry the Quality assurance CE Mark. And are tested to EN standards that meet both BRITISH & EUROPEAN Standards. All our products meet or exceed the necessary standards and are designed to work for the build's life. Isocell Airstop's 28 years of development and expertise stand behind every solution.


For 28 years, our products have been used in some of the most extreme climates in Europe, where temperatures range from freezing winters to scorching summers and have stood the test of time.


Isocell Airstop performs continuous in-house testing in our laboratory and technical facility as part of our ongoing stringent quality control.


Besides cellulose insulation, ISOCELL has proved itself to be a competent and innovative troubleshooter in airtightness for both craftsmen and installers. Since 1995 roof underlays, wind seals, vapour barriers and adhesive systems have been developed and distributed under AIRSTOP and OMEGA—over 600 airtight measurements annually on building sites at home and abroad provide comprehensive data and new knowledge.

Air and wind tightness are decisive factors for efficient thermal insulation. Through non-airtight sections – so-called leakage – in the building’s envelope, warm indoor air can flow freely to the outside and is replaced by cold outdoor air. This cold air must be warmed again by the heating system. Research has shown that even when houses are well insulated, the proportion of thermal loss through non-airtight areas and thermal bridges can be up to 60 % of the total loss. Direct results of leakage in the building envelope are damage from condensation, reduced performance of acoustic insulation, dry room air and cold floors on the ground floor.

How much the insulating effect of a building component is diminished has been measured at the Institute for Building Physics in Stuttgart: a component  (typically used in prefabricated housing), with outer measurement 1 m x 1 m and 14 cm thick, has a U-value 0.3 W/m²K when tight. If there is a 1 mm wide continuous gap of only 1mm, the U-value is reduced to 1.44 W/m²K.



Even in well-insulated houses, leakage in the building's envelope causes energy loss of up to 60 %. Through these gaps and cracks, cold air forces its way in and needs to be re-heated by the heating system. The cold stays outside when a wind and airtight layer has been appropriately installed.


Improved thermal insulation Protection from condensation

A professionally installed membrane to the building's envelope protects from winter cold and summer heat. Gaps in outer construction components impair the insulation's effect considerably. Here is an example: for a building component with an outer measurement of 1 m x 1 m and 14 cm thick, the U-value deteriorates from 0.3 W/m²K to 1.44 W/m²K if there is a 1mm wide continuous gap.


Air and wind tightness has a massive impact on the energy rating of the building.

What's your colour? 


Isocell Airstop energy rateing
Energy Rateing


Adhesive tapes and sealing compounds – energy loss lies in small details. The increasing demand for airtight building envelopes within the low and passive house-building sector requires simple yet complex solutions. Due to continuous research and development and the ongoing collaboration with installers, our primary focus is, besides the highest standard of quality, on ease of handling and product installation. Before the product is launched, laboratory tests are carried out by partners and independent testing facilities for product quality and suitability; once the product passes all necessary tests, we then focus on the ease of handling and installation. These trials are carried out in real projects and our in-house training and lab facility. Such practices have led to specific characteristics being incorporated into our final products. In producing adhesive tapes, pure acrylate adhesives are used  (we add no resins); this guarantees that the bonds are resistant to ageing for over 30 years (Certificate from Kassel University). Other products with cheaper resin adhesives fail as the adhesives dry out relatively quickly and then lose their bond. Sometimes it's what you can't see that makes the difference. 

Isocell Airstop airtightness test

Prevention of draughts entering the structure.
The proverbial ‘tornado from the socket’ negatively impacts the comfort of the living space. Everyone has experienced cold feet – caused by air drawn into the building’s envelope through unsealed structures. As this cold air is heavier, it moves to the lowest point in the room, the floor. Then, when air from outside enters through cracks,

even the best insulation is useless. by using our system; you ensure the envelope of the structure performers in a manner that maximises your overall building performance and comfort. 

Isocell a healthy home

Condensation within the building makeup leads to a noticeable deterioration in the U-value. However, a more significant problem is the subsequent severe damage to the structure if moisture cannot dry out quickly. It is estimated that two-thirds of all damage from moisture in the construction sector can be traced back to a lack of airtightness.

Unsealed areas within the building envelope can negatively impact the indoor climate as dust and fibres from insulation permeate the air. Structures sealed with ISOCELL products ensure a controllable healthy living environment that can be regulated through systems such as a heat ventilation recovery or planned passive ventilation. 

Optimum functioning of air-conditioning systems/heat ventilation recovery 
Where air-conditioning and or/heat ventilation recovery systems are used, a building must be exceptionally airtight. The maximum permitted value for airtightness of the building envelope is in accordance with DIN 4108-2. That is twice as high as for buildings without ‘mechanical


Noise stays outside

Even with good acoustic insulation, the sound entering a building can increase due to gaps in the building’s envelope. Noise enters through even the most minor cracks. With ISOCELL airtight systems, annoying sounds stay where they belong: outside.

Isocell Airstop Humitidy control
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