Facade Cladding

Elastic sealants based on synthetic elastomers such as polysulphides, silicones or polyurethanes allow the periodically alternating movements of building structures caused by temperature fluctuations to be followed in a consistent manner. It has gone unnoticed by some that owing to the development of modem elastomaic sealants, a new field of application has emerged - the load-bearing adhesive joint 

The first step towards load-transmitting and movement-absorbing adhesive joints was taken around 1963 with the introduction of structural glazing in the USA. Decorative claddings are sometimes taken for granted, in particular for commercial and residential buildings and for new buildings and refurbishment work. 

Facade panels made from HPL (High-Pressure Laminate), natural stone, stoneware or aluminium are used. The frame is generally made of aluminum but can also be made of planed wood. Use of such a variety of materials calls for an adhesive which is compatible with a wide spectrum of substrates and capable of absorbing, within certain limits, the different thermal and hygroscopic movements between panel and frame. 

Thin panels are more economical and due to their low weight, allow costs to be saved with the frame overall. In the case of screwed or riveted fastening, forces are only absorbed by the face of the holes. Thin panels therefore need more fastening points. Elastic bonding spreads stress evenly (see Fig. 14) and acts in the same way as an infinite number of fastening points. 

Whereas for industrial use where bonding can be executed directly inside appropriate factories, the bonding of facade panels has to be done on site (Fig. 106), under varying climatic conditions and in difficult environments (often dust-laden ones). 

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On account of their insensitivity to solar radiation, some polyester resins are particularly suitable for weather-resistant topcoats (e.g.. facade claddings, blades of shutters and Venetian blinds, vehicle claddings, metal signs). Melamine-formulated paints are economical and have a well-balanced property profile. Polyurethane-formulated paints have an even better processability and weather resistance (colorfastness, chalking resistance) [2.92],... 

An increasing number of projects in the UK, Germany, Switzerland, the Netherlands, Denmark, Sweden, Japan, the United States and several other countries use PV panels as wall cladding on large scale, often multistorey bttild-ings, referred to as PV facades. ... 

Fibre reinforced cements are extensively used in a variety of cladding applications, ranging from small shingles up to large facades units of several metres in size [91-96]. In these applications the composites used are usually thin section components, where the fibres are the primary reinforcement. Glass, polypropylene, carbon and cellulose fibres have been used for these applications. The mechanical and physical properties ofthese composites can be quite different, as demonstrated in Figure 14.21 and Table 14.3 [97]. 

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