With an increasing number of commercial window installations involving the frames projecting externally into the cavity or insulation zone, the sealing of the frames back to the internal structure becomes critical in order to ensure weather and air tightness (unless this is detailed further inside). Typically, membranes are fitted (EPDM or ‘intelligent’ membranes) and have to be carefully located and bonded to the frame around the fixing brackets and to the backing wall.

Tremco illbruck has launched a new innovative and green system which creates a structural surround forward of the window opening and which seals the windows on three levels (weather and air tight and providing thermal insulation). The system is fully tested by ‘ift’ Rosenheim and is capable of sustaining dead loads of 200 kg/m. The structural element is illbruck PR007, a strong, high density recycled PU material, which is rot proof and mould and mildew resistant.

The main bonding of this profile to the structure via the backing wall is by using Tremco illbruck SP340 hybrid adhesive, a green product that is isocyanate and silicone free and supplied in foil packs, minimising site waste. A minimal number of fixing screws are necessary to compensate for substrate variations and ambient conditions and to facilitate immediate fixing of the windows following installation of the profile prior to full curing of the adhesive. The windows are sealed to the illbruck PR007 profile using illbruck TP652 Compriband Trio Plus impregnated foam tape and illbruck ME500 Duo Flexible Window Membrane. The windows are fixed into the system using through-frame distance screws which negate the use of frame packers and potentially costly fixing brackets. Further cost reduction is achieved by avoiding the need for steel or aluminium angle profiles frequently used to provide dead load support under the window cill.

The installed system provides continuity of any surrounding insulation, preventing cold bridging and also providing acoustic benefits. If windows need to be replaced after their service life, this can be done with minimal effect and expense to the surrounding structure.

The illbruck projecting window system is supplied in a pack containing all of the necessary materials, including: PR007 rigid profile, PR008 insulation wedge profile, SP340 hybrid adhesive, primer, and Compriband TP652 Trio Plus impregnated foam tape.

Use of and introduction to the system is fully supported by Tremco illbruck’s highly trained team of technical service advisors.