The current economic crunch and the call for more energy-efficient buildings have led companies to reinvestigate the use of traditional construction materials and to consider alternative composites, such as glass reinforced plastic (GRP), for some applications.
Originally developed in 1938 for use in insulation, GRP is highly durable and combines a number of attributes including high impact strength, low weight, dimensional stability and weatherability. GRP has been used successfully in projects such as the new 3 050m² Masscash Holdings trading warehouse, contracted to Scheltema. The warehouse, with an apex height of 12m which affords the client flexibility in its racking layout and allows for bulk storage of up to six metres, was one of the first large-scale projects in the Western Cape to make use of the non-fragile GRP sheeting known as Modek GRP Walk-on.
Internationally, landmark buildings such as the Amex stadium, The Oval Cricket Ground, the Emirates Stadium, and Twickenham Stadium in the UK, Thomond Park in Ireland, and Dubai International Airport have all made use of GRP cladding, rooflights and canopies. GRP has also been used to form bridge decks and walkways in countries such as the UAE.
In high-rise buildings GRP panels can be used as cladding on other structural materials, providing a protective cover on interior or exterior walls. The ease of fabricating large panels in GRP and the material’s versatility in terms of colour, shape and texture, offer particular advantages in cladding applications.
Christo Pienaar, marketing director of Modek and Ampa Plastics, both companies that supply GRP sheeting to the construction industry, says, “Plastic cladding offers an attractive finish and is easy to clean. It is strong and can withstand a great deal of stress as well as extreme temperatures, marine conditions and strong winds. It is also ideal for use in buildings where chemical resistance is required.”
For industrial applications Modek produces opaque GRP sheets using high-grade isophthalic chemically-resistant polyester resin. This cladding is used in battery manufacturing plants, for example, as well as refineries, poultry farms and galvanising works.
Modek supplied over 7 400m2 of isophthalic sheets to the Skorpion Zinc mine in Namibia, to replace the polyethylene cladding that had corroded as a result of chemical degradation. The company is currently working on a similar project with Namdeb.
As well as durability, GRP roofing and cladding offer the additional benefits of high thermal resistance, moisture- and mildew-resistance, mechanical strength and reduced installation time – which can be up to 50% shorter compared to alternative materials – because it is easy to cut, drill, fit and carry on site.
Pienaar reports that like GRP, polycarbonate cladding is also becoming more popular for roofing and cladding applications.