Isocell Airtightness Products

Smart solutions for high performance buildings

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Integrating the appropriate membranes into a construction not only strengthens the performance of insulation and energy efficiency but will also prevent mould, rot and structural damage, not to mention a considerable improvement in air quality.

Whether you are constructing a standard, low energy or passive home, the range of building wraps, including vapour barrier, wind seal and roof underlay, and window and barrier tapes are available to safeguard your building and guarantee a safe and energy efficient environment.

Advantages of Isocell products

  • Energy efficiency. Air and wind tight products help prevent energy loss due to excessive air exchange.
  • Moisuture control: Isocell airtightness products prevent unwanted air movement but still allow moisture to escape using function films. 
  • Easy to install: A wide variety of tapes, grommets, and sealants are available to make sealing the airtight layer a breeze. 
  • Technical knowledge: Siegware can provide technical assistance for almost any situation encountered on the construciton site. 

Available now at Siegware

Below is a selection of the most commonly used Isocell products available at Siegware. Siegware maintains a healthy level of of stock in our Australian warehouse available for quick dispatch. Siegware can also order on demand other specialist products on request. 

AIRSTOP DIVA+ Fabric Reinforced Membrane

With AIRSTOP DIVA ISOCELL have developed a transparent, tear-resistant vapour barrier. The special membrane reacts to the moisture in the surrounding atmosphere. With sufficient solar insolation the moisture is transported to the interior of the construction and favourably influences the drying of construction components during the summer. A strong PP membrane guarantees very good stability.

Diva+ vapour retarder installation example

FH Forte Fleece Vapour Retarder

A transparent vapour retarder for the airtight layer in roof and wall constructions. In general FH FORTE Fleece Vapour Retarder is suitable for use in building components that are non-vapour retardant on the outside. In constructions that are well sealed on the exterior (e.g. flat roofs, renovations) the low sd-value guarantees a high degree of drying towards the interior during the summer months.

FH Forte installation example

Omega Mono 230SK Duo

A non-vapour retardant roof underlay for installation directly on the thermal insulation or the wood sheathing. Suitable for rainproof under-roofs as well as for under-roofs with increased rainproof properties with a roof pitch of > 15° and a snow load of up to 4.0 kN/m².

Omega Mono 230SK Duo installation example

Omega Light

Extremely diffusive vapour permeable roof underlay for installation directly onto the face of the thermal insulation or wood sheathing. 3-layer fleece combination. Suitable for ventilated facades (walls) and ventilated pitched roofs.

Omega Light installation example

Timber Protect SK:

TIMBER Protect SK is a combination of fleece coated with an impermeable membrane on both sides and a specially matched polyacrylic adhesive. The tear-resistant synthetic liner facilitates handling. Construction elements can be bonded together over the entire surface with the wide sheets as protection during transport and the construction period. Joins between sheets can easily be made lengthwise along the marking grid and diagonally with 10 cm overlap.

Application example of Timber Protect SK on internal floors


To guarantee air and wind-tightness for the skin of a construction it must have the appropriate foils or panel materials providing a permanent seal at overlaps, gaps, joints and penetration points. AIRSTOP ELASTO Adhesive Tape is slightly expandable with adhesive generously applied. Availabe in a variety of widths and lenghts. Split liners also available for tricky installations such as corners joints and beam penetrations through the airtight layer. 

Airtight sealing of membrane to floor using AIRSTOP ELASTO

UVAU and Febasoft Window Tapes

Window tapes for airtight sealing around windows on interior surfaces. Suitable for all window types such as timber, uPVC and Aluminium. Varients for inside and outside applications available.

Febasoft ES being used to seal around uPVC window. 

AIRSTOP Pipe and Cable Grommets

Grommets are an easy to install solution for where pipes or cables must penetrate the airtight layer. The grommet is sized according to the penetration thickness and angle. 

AIRSTOP grommet being used to seal around pipe penetration

Select the Product Page for information and advice to get the best results



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