"vapour control layer"

This Awkward Passivhaus design barrel roof made airtight with ease with Spray applied Airtight vapour control membrane Passive Purple.

A case study of the use of Airtight White Intelligent Airtight Liquid Vapor Control

Global warming and climate change are two terms found increasingly in headlines around the world. Initiatives such as the Kyoto Protocol have brought these issues to the forefront and provide a framework and objectives for reducing greenhouse gases (GHG). GHG are heat trapping gases, such as water vapour, carbon dioxide, or methane that absorb the earth’s heat and hinder it from being released into space. As levels of GHG build up in the atmosphere, a greenhouse effect takes place that warms the earth’s atmosphere and makes global climate change inevitable. A?itudes on environmental issues are changing worldwide. Developed nations are commi?ing to reducing GHG emissions to 5.2% below the 1990 baseline by 2012. Notably, Canada has commi?ed to reducing its GHG emissions to 6% below 1990 levels, which corresponds to a gap of 29.1% of where the nation is and where it wants to be. An ambitious undertaking, considering that Canada’s GHG emissions have been steadily on the rise over the years and in 2004 was actually 26.6% higher than 1990 levels. On a positive note, in the last two years emissions have started to decline, but there remains a long way still to go. =e quest for a greener Canada continues and helping to lead the way to a greener Canada is the nation’s steel industry, which is making great strides in reducing GHG emissions, conserving energy, and lessening impacts on our air, water, and land.

One of the most common questions asked by homeowners about the installation of their steel roof is whether an underlayment is needed. The answer to this question is “yes” in most situations. The underlayment plays a critical role in controlling the migration of condensation that might develop on the underside of the steel sheet thereby preventing accumulated water entering the building resulting in costly damage.

What is Oil-Canning? Oil-canning is associated with all thin sheet metal products and occurs in the wide flat portions of the cladding profile. It is seen as a series of standing waves, or regular bumps and hollows alternating along the flat length of the panel. This waviness, when viewed under certain conditions, can be undesirable aesthetically and may not meet with the owner’s expectations. The CSSBI wants to help avoid this situation. The cladding manufacturers are aware of the potential for oil-canning in the cladding profiles and can help minimize the effect. It is important for the proper steps to be taken during manufacturing and installation to produce a quality finished product; therefore, specifiers should insist on product from a reliable, experienced cladding manufacturer, like a CSSBI member company. Quality control, however, cannot end on the shop floor. The building project needs the cooperation and knowledge of everyone involved to enhance the quality of the finished job. Oil-canning is a phenomenon that can be managed if the following factors are considered at the beginning of a project.

Buildings consume one-third of all energy and two-thirds of all electricity generated. Cool metal roofs can help reduce energy consumption by lowering cooling loads with their wide array of finishes, designs and colors.Cool metal roofs are energy-efficient. • The roof can have the greatest impact on the energy use of a building. On a typical summer afternoon, a light-colored, more reflective roof that reflects 80 percent of sunlight will stay about 310C (550F) cooler than a darker roof that reflects only 20 percent of sunlight, as reported by the Heat Island Group of the Lawrence Berkeley National Laboratory. • Cool metal roofs are an excellent option for commercial retrofit applications because they can be efficiently installed with above-sheathing ventilation, allowing heat to dissipate through the ridge vent in hot weather while acting as an insulating layer when it is cold. Metal roofs can result in as much as a 30 percent reduction in heat gain through the vented roof. • Metal roofs provide the optimal foundation for photovoltaic installations since the roof can be expected to last longer than the PV system it supports. • Wall and roof solar heat recovery systems can be integrated with steel cladding and used to provide air, water or process heating needs. • Cool metal roofing is available unpainted, with thermosetting coil-applied paint finishes, or with granular-coated surfaces. This family of roofing can achieve solar reflectance of over 70 percent, meeting the EPA Energy Star Roof Products Program performance criteria. • Emittance as high as 90 percent can be achieved for painted and granular-coated metal roofing. • Painted metal roofs retain 95 percent of their initial reflectance and emittance over time. They resist the growth of organic matter and shed dirt more readily than other materials. • Cool metal roofing can help to mitigate the Urban Heat Island Effect because of its high reflectance, which can reduce ambient air temperatures. Cool metal roofs are cost-effective. • Metal roofing has low life-cycle costs, making it the choice of many school, government, commercial, industrial and institutional building owners. • Due to its light weight per unit area, structural savings can be realized in a building when compared with heavier non-metal roofing alternatives. • For re-roofing projects, metal roofing can often be applied over the original roof, saving removal and disposal costs. • Metal roofing is fully recyclable when ultimately removed as part of building renovation or demolition, allowing it to credibly claim both recycled content and 100 percent recyclability by recognized definitions. The product’s recyclability also provides significant savings on construction removal and disposal costs.

Sustainability, durability, fire resistance, structural performance and cost-effectiveness are some of the strongest reasons for using structural steel or cold-formed steel framing in mid-rise building construction. As a dependable, noncombustible material, steel-framed structures provide a wise investment for builders and the occupants who live and work in them. Steel structures provide long-term, consistent performance. • Steel framing will not rot, warp, split, crack or creep. • Steel framing is not vulnerable to termites. • Steel framing does not expand or contract with moisture content. • Steel framing is produced in strict accordance with national standards, with no regional variations. Steel is a noncombustible material and will not contribute to the spread of a fire. • Because steel is noncombustible, it reduces the fire risk to occupants, firefighters and property/business owners. Steel framing improves design efficiency, saves time, and reduces costs. • Steel framing provides a significantly greater strength-to-weight ratio than wood. • Steel framing allows for larger bays and wider frame spacing than wood construction. • Increased flexibility in bay spacing and framing layout maximizes usable floor space for owners and tenants. • Steel is typically fabricated off-site, reducing on-site labor, cycle time and construction waste. • Shorter construction time results in earlier occupancies and lower financing costs. Steel structures perform well during earthquakes and other extreme events. • Steel is a resilient material, with reserve strength and ductility that result in significant advantages in natural disasters such as hurricanes and earth- quakes, and in other extreme events like fire and blast. • Steel construction is engineered to provide a reliable, consistent load path. • Steel construction employs quality control and quality assurance procedures to ensure that the project requirements are met. Steel framing provides environmental benefits and complies with sustainable building standards. • Steel framing results in less scrap and job site waste than lumber. • Structural steel is continually recycled with a current recycling rate of 98 percent, meaning that these steels will still be in use hundreds of years from now, lessening impacts on future generations. • Steel, when recycled, loses none of its inherent properties and can be recycled into different products such as cars, bridges, cans, etc. • Steel can be used to comply with the requirements of sustainable design standards such as the International Green Construction Code (IgCC), ASHRAE Standard 189.1 (Standard for the Design of High-Performance Green Buildings Except Low-Rise Residential Buildings), and the National Green Building Standard (ICC-700). Steel can also provide credit points for green building rating systems like the USGBC’s LEED (Leadership in Energy and Environmental Design) and the Green Building Initiative’s ANSI/GBI-01 (Green Building Assessment Protocol for Commercial Buildings).