As one of the most important design features of a building, roofs serve a greater purpose than just sheltering – Walls & Roofs looks at the latest innovations and applications in roofing.
Modern roofs have become more than a simple shelter to protect a building’s interior spaces. Innovation and technology have made roofs one of the most important design elements in modern construction – much more than the simple flat roofs of more than a century ago, which were covered in corrugated iron or straight-run bitumen.
Early roofing featured layers of heavy paper, covered with pine tar and sprinkled with sand. Asphalt products evolved from mid-19th-century composition roofing. Manufacturers assembled built-up roofing’s site-layered components to produce long strips of factory-assembled roll roofing.
Single-ply roofing makes up as much as 55% of the global roofing market share.
Reflective roofs reduce ambient temperature in a building by reflecting heat away from the structure. This reduces the cooling load and ultimately provides a greater degree of energy-efficiency in a building.
This move towards user-friendly, environmentally-friendly and energy-efficient products continues to drive technological milestones in roofing. A recent trend is the construction of commercial roofs with photovoltaic (PV) cells embedded in PV-cell membranes.
Sandton City’s 2011 expansion was capped with an environmentally-friendly climate envelope roof. The magnificent dome atop the Protea Court formed part of the shopping centre’s redevelopment and expansion project, which involved interior refurbishments and 30 000m² of new retail space.
The Protea Court roof was created with a product called Texlon, which is made up of multiple layers of foil known as ethylene-tetra-fluoro-ethylene (ETFE), which is a modified polymer. ETFE consists of pneumatic cushions restrained in aluminium extrusions, supported by a lightweight structure. The cushions are inflated with low pressure air to provide insulation and resist winds.
Texlon combines exceptional light transmission with high insulation. Each layer can incorporate different types of solar shading, enabling the design to optimise the aesthetic and environmental performance of the building envelope.
The building envelope is the interface between the interior of a building and the outdoor environment. In most buildings, the envelope is the primary determinant of the amount of energy used to heat, cool and ventilate.
Pan Mixers South Africa (PMSA) recently introduced a new range of concrete roof tiling machines to the Southern African market.
The SPS712 roof tiling machine is manufactured by the Swedish-based roof tile expert ABECE. In order to ensure ease of maintenance and cleaning, the extrusion head of the machine flips upwards. PMSA will manufacture the model locally according to demand.
On the topic of local innovations, MacSteel Roofing, who is currently involved in the roofing if the new Rosebank Mall extension, has introduced its concealed-fixed sheeting to the market.
Its roofing profile covers an effective 440mm and is generally roll-formed on site from G550 MPa high-tensile steel to any practical length that is manageable by the contractor. The centre rib is designed to move freely to allow the profile to absorb wind gusts. Due to the nature of the rotation mechanism, the male and female only start to interlock at wind pressures of around 1,2kN/m². This patented interlocking mechanism makes the product unique to the South African market.
As the earth becomes more exposed to the effects of greenhouse gasses, it has become a usual occurrence to see harsh weather or natural disasters in areas usually unaffected by these conditions.
A world of choice
With all the emphasis on the environment and cost-efficiency, aesthetics are usually given less attention. However, great ceiling designs can give a room an inimitable and individual character and ambience that could not necessarily be achieved by other elements. Here are a few examples of impressive modern ceiling designs that add an extra dimension to interior spaces:
1. Recessed ceiling lighting.
2. Paris department store with elaborate natural roof lighting.
3. Elaborate classic wood-trim ceiling.
4. Glass flower ceiling at the Bellagio Hotel.
5. An acoustic wood ceiling at the Soka University of the Performing Arts.
6. Classic tray ceiling.
7. “Up-cycled” pine canopy ceiling.
The lightest roofing material ever
A Santa California-based company recently developed a new green roofing product that is light, strong and environmentally-sustainable, using advanced engineering polymer materials.
The top layer of the roofing product is made from a highly weatherable material, which has been used for more than 40 years for outdoor applications, yet it has never been used in roofing technology until now.
According to Jim Stewart, PhD, an environmental scientist at the Modern Energy Corporation, the weight of roofing materials has the overall greatest environmental impact in almost every environmental impact category listed. Lighter weight roofing materials alone affect the environmental impact from birth to grave more than any other factor. Lighter weight roofing materials decrease the raw materials used, manufacturing and transportation energy use, workers and homeowners safety, landfill use and waste. Weight is also an easy criterion in determining general environmental acceptance criteria.
• It reflects heat back into the atmosphere and provides insulation, both of which dramatically reduce heating and cooling costs.
• It is 100% recyclable with 0% waste in manufacturing.
• It is eight times lighter than the average roof.
• It uses the least amount of the earth’s resources of any roofing material.
• It is engineered to withstand the most extreme climatic conditions – high winds, earthquakes and fires.
• It is artistically crafted.
• It is manufactured in 2×4 panels, enabling roofers to install it quicker and easier – and with 70% less nails.
• It is offered in multiple colours and designs.
Full thanks and acknowledgement are given to PMSA, MacSteel, Liberty Property Management, BuildingsMagazine.com and the Environmental News Network for the information given to write this article.