– Written by Nichelle Lemmer
Constructing and designing a roof over a building consists of various elements that should be selected carefully to complement each other in creating a secure and sustainable structure over a client’s head.
Walls & Roofs talked to various industry experts about new products and trends on the market that could make it easier for specifiers to choose the right product that suits their clients’ needs.
Ceiling boards can play an important role in creating a comfortable and safe internal environment in a building. Craig Cronje, sales and marketing director, Everite Building Products, says sound and thermal insulation, water resistance and the fire-resistant properties of a ceiling each has a role to play at some stage during its lifespan to a greater or lesser degree. “Sound and thermal insulation is a given, and there are many add-ons over ceiling-insulating materials to up the performance of a ceiling.” He says that not all ceilings are able to withstand the surprise of a burst geyser, a leaking pipe in the roof and to the other extreme, fire.
According to Cronje, the South African weather and associated lifestyle have led ceilings to become a natural extension from indoor to outdoor. “However, not all ceilings can withstand damp or high humidity before they begin to sag and disfigure, so no matter if you are building or renovating, it’s important to choose the right ceiling board from the start.”
Nutec ceiling boards are manufactured from a combination of cement, silica and organic fibres, and are asbestos-free. “These materials have a considerable strength in their own right and will not deteriorate with age.” “Nutec ceiling boards are ideal for general use and because it is not affected by moisture it is perfect for use in damp areas such as kitchens, bathrooms and verandas, as well as for under eaves linings,” he adds.
Cronje says Nutec fibre cement is fire-resistant and does not burn when tested in accordance with the South African National Standards test methods. “These ceiling boards also show no damage from termite or rodent activity or bacterial growth.”
Sustainability, aesthetics and practicality
Luigi Zito, general manager of Hunter Douglas, says ceilings made out of wood and metal have a longevity quality that enhances the lifespan of the product. “Our metal ceiling products are manufactured from recycled material and add to the sustainability of a project as it can be used for long periods of time without requiring any maintenance.”
He says these ceiling systems deliver an appropriate fire-retardant rating and also contribute towards sound absorption. Zito believes that the wheel is in no need for re-invention. “Our products are tried and tested, which means that a specifier takes a limited risk in choosing our products.” He adds that it is of utmost importance that a ceiling system is aesthetically appealing and practical when applied in a project.
Lisa Reynolds, Saint-Gobain’s Construction Products’ Technical and Specification Director, says ceiling boards contribute to the energy performance of the roofing/ceiling assembly. “The thermal value of ceiling boards help to save energy.” She says that when constructing an energy-efficient roofing system, the first step is the installation of a ceiling. “According to the new SANS 10400-XA standard, ceiling boards cannot be used alone to comply with the energy-performance of roof standards. It still needs to be combined with insulation product to get the prescribed R-value.”
Reynolds says that the new SANS 10400-XA energy-efficiency standards set new requirements for insulation in buildings that need to be adhered to.
“The regulations specify a certain R-value to components of the building shell in six different climate zones.” She further explains that a different R-value is specified for the various climate zones and insulation products need to deliver a particular intervention R-value to be in line with the regulations.
According to her, specifiers and architects can use a combination of products or let any of the products stand alone, just as long as the overall R-value for a roof is reached. “The SANS 10400-XA was drawn up with the aim of reducing the need for energy consumption in a building. If buildings are constructed on energy-responsible principles, the energy that is saved will ultimately help the country in reaching its goals to create a more sustainable energy supply.”
Buildings that are not regulated by the SANS 10400-XA insulation R-value are warehouses, factories and outdoor sport facilities, as these buildings are not subjected to the need for a comfortable living space.
Understanding the regulations
The Thermal Insulation Association of South Africa (TIASA) recently published guides for the use of various types of insulation to clarify and promote the understanding of the new SANS 10400-XA standards. The objective of the guides is to determine the total R-value of common roof construction systems, increase energy-efficiency, reduce the environmental impact of building projects and assist all parties in the construction industry to comply with the new requirements of the standards.
The organisation says climate change has become a reality. In one of the formal guides published by TIASA, it states that man-made buildings, together with the component parts of material used in construction, may not always achieve the required levels of performance in resisting heat, cold, moisture and noise to provide a comfortable and healthy environment.
According to TIASA, thermal insulation materials, used singularly or in combination, are able to contribute substantially in conserving energy, many of which depend largely on air, be it through entrapment or division to be effective. “However, air is also the conveyer of dust and moisture, both of which impact to a certain degree on the performance and efficiencies of all insulating materials,” the association says. “Their performances are further influenced by a rise and fall in temperature.”
Read more about the guides in another article in this issue of Walls & Roofs that features these publications.
Easy installable insulation
Melvin Roberts from Isolite says the easy installation of a product is important as it opens the door for contractors, do-it-yourself customers and farmers to use it. One of their systems is designed around a framework consisting of an aluminium T-section and a PVC T-section that comes together to form an H-section, with the aluminium used as a frame and the PVC as a clip-on finish on the surface.
He says that in over-purlin applications the aluminium section can be butt-joined at any point along the slope, even between the purlins. “This can be done by making use of the PVC section at the joint.” In suspended ceilings, their product comes with a unique hold-down clip that can be used with the standard Donn System, which is easy to install and remove, but will firmly hold a 40mm panel in place.
Roberts says it is important to develop and manufacture green products. “One of our green products has a surface that is completely washable, contains no glue or toxics gases, and is therefore safe to specify for use in food-processing areas.
He says Isolite has undertaken to recycle all expanded polystyrene waste material and today recycles expanded polystyrene from outside sources.
Waterproofing, coatings and torch-on’s
Elrene Smuts, marketing communications manager of a.b.e Construction Chemicals, says it is important to invest in new technologies and products to heed to the call of market needs. She says the company constantly provides new technologies, while ongoing research and development programmes create new products that will add value to their customer base.
According to her, the company aligns itself with international principles and uses existing channels to introduce new products that further enhance its current product range. Being a member of the Green Building Council of South Africa also helps them to promote and recognise environmental issues. a.b.e created a new innovative ECO-waterproofing range, which was launched last year, to meet the current need for green products.
Alex Lepley from Iluz Brothers and Bitumproof waterproofing systems have successfully started supplying the industry with green waterproofing products and are slowly influencing the way chemistry the general market is doing waterproofing. “Chemical waterproofing is not only better for the environment, but it is also brilliant for the user and the building.” She adds that from foundation to roof-top solutions, chemical liquid spray-on waterproofing is 100% waterproof.
She says that torch-on is a conventional system used by contractors in the industry for years. She explains that it is a method of waterproofing that requires rolls of thermoflex. “As much as the torch-on system is used by the industry, this system is not the best option to waterproof your residential, commercial or industrial buildings, as the construction industry is now required to construct buildings with less of a carbon footprint.”
She says waterproofing systems that have a green footprint will be water-based. “Water-based liquid waterproofing uses an airless machine for application.” Lepley adds that using such a system, a two-men crew is able to spray up to 500m² in a work day. She explains that water-based products will be odourless and non-toxic. “Water-based products are available on the local market.”
Relying on chemistry
Lepley is of the opinion that spray-on waterproofing is becoming the next best thing in the waterproofing industry. “Liquid-spray applied waterproofing technology has been around for years, but South Africa has finally seen the benefits of waterproofing with a spray-on application.”
She believes that the benefits of spray-on waterproofing can be used as a quick, sufficient, seamless waterproofing application. She goes into detail about the advantages of using such a product. “It is odourless and non-toxic and is an excellent preventative treatment for rust.” She says it also has acoustic qualities and provides thermal insulation. According to her, spray-on waterproofing systems are also user-friendly. “There is even a spray-and-seal application that is one of the most innovative products on the market.”
Uwe Schlüter, business development manager of MiTek, says the roof-truss industry is a substantial player in the total construction industry and as such is always driven by market forces and requirements to improve and innovate. “This also drives the system providers,” he says. “Specifiers can look out for the development and improvement of timber and light-gauge steel roofs rather than seeing growth in the development of totally new materials.”
He says there are many new and unconventional ways to use trusses, such as creating a roof-garden support structure. “Floor trusses could also be created instead of using concrete slabs.” He says that an interesting way of using roof trusses is to create an attic roof structure. “This expands the livable area and is a common sight in Europe. One could also apply trusses in formwork for bridges or tunnels.”
Schlüter says that in accordance with the latest code requirements for more adequate fixings for roof trusses, MiTek has launched a new “wall-tie” product. The product consists of metal straps that are pre-perforated with nail holes for easier fixing in specific lengths. “The application of the product depends on the load requirements of the roof trusses,” he adds. “The ends of the straps are splayed for improved embedment in the wall structure.”
According to Schlüter, appropriate software for the overall design of light-gauge steel-roof systems will be further developed. “The software will feature the overall design of these structures from roof to floors to walls in a 3D format, calculating all the required load paths and considering all the various final solutions.” MiTek is already offering such a software package to licensed users.
Staying on top of the roofing and ceiling industry can be done by doing extensive research on the wide variety of new products that are entering the market every year. Exploring the opportunities, some of these products offered to lower a building’s carbon footprint could go a long way in saving and conserving energy. By supporting these products, specifiers and architects can do their bit to green the construction industry.
Full acknowledgement and thanks are given to MiTek, Iluz Brothers, Isolite, Saint-Gobain, Everite and a.b.e. Construction Chemicals and TIASA for the information given to write this article.