"roof finish underlays and insulation"

A question that homeowners often ask about steel roofing is “Will a steel roof be noisy when it rains?”. We’ve created this fact sheet to help answer that question. Residential steel roofing is available in many shapes and forms. The forming process provides not only strength, but when coupled with high quality build finishes, absorbs and deadens much of the noise. With the home insulation standards of today, you should not notice any difference in noise levels between roofing materials. 

It’s a fact that buildings consume two thirds of all the electricity produced in North America and one third of all the energy produced in North America. While it is recognized that adding insulation under the roof surface can reduce cooling and heating costs, there is a diminishing return on the strategy of increasing insulation to conserve energy costs. This is where “cool roofing” can play a role in further reducing the energy consumed, and in minimizing the Heat Island effect created in the big urban cities. Cool roofing relies on sustainable, energy efficient, coated steel products, in a wide variety of finishes, colours, textures and roofing profiles. It conserves energy through its properties of reflectivity and emissivity

Architects and Specification Writers are increasingly selecting unpainted metallic coated steels for architectural roofing and cladding applications on building exteriors where they want a “Silver” metallic finish. This is occurring more frequently, and even on “prestige” type projects. The Canadian Sheet Steel Building Institute whose fabricator members manufacture a wide variety of building panel profiles for roofing and cladding applications, are being asked to supply unpainted (natural finish) galvanized or resin coated 55% Aluminum-Zinc coated steel for these architecturally exposed end uses. Oftentimes, these materials are specified because the designer finds the natural finish of these products very appealing and sometimes because of material cost savings opportunities. This Fact Sheet has been developed to provide guidance in material selection and provide information on the Architectural Metallic Finishes that are available for highly visible steep slope roofing and cladding applications. 

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.

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

Steel has been used in North American construction projects for more than 150 years and still remains one of the strongest, most durable and economical building materials available today. Although steel has been traditionally associated with high-rise buildings, bridge structures and commercial and industrial projects, it is rapidly emerging as the logical material of choice for residential construction. Cold formed sheet steel panels are lightweight, economical, easy to handle and represent a high quality alternative to traditional roofing materials. Environmental and economic considerations have prompted many residential homeowners to investigate alternative building materials and methods, and steel roofing panels have proven technical benefits as well as excellent recycling capabilities which make them an increasingly popular choice. This follows the long-time use of steel roofing in commercial construction where steel has built undisputable quality and performance records. 

When a homeowner is considering the purchase of a steel roof a common question is whether it will increase the risk of a lightning strike. After all, steel is highly conductive, just like the materials used in lightning rods, so doesn’t it stand to reason that the steel roof will attract lightning? The short answer is, NO, steel roofing will NOT increase the risk of a lightning strike in any way. For all intents and purposes, nothing ‘attracts’ lightning. Lightning occurs on too large of a scale to be influenced by small objects on the ground, including steel roofs. The location of the thunderstorm overhead alone determines where lightning will hit the ground. A lightning bolt that is several miles long, generated by a cloud that is more than 6 to 10 miles high, is not going to be influenced by an object the size of your house. 652 Bishop St. N., Unit 2A, Cambridge, Ontario N3H 4V6 • Tel.: (519) 650-1285 • Fax: (519) 650-8081 • www.cssbi.ca The descending stepped leader of a lightning bolt doesn’t ‘decide what to strike’ until it is very close to the ground. When a cloud-to-ground lightning channel is forming, it is going to strike the ground where the opposing charges are greatest, directly underneath the storm’s most electrically active region. If you are standing at that exact location, you will be hit, even if there’s no metal within miles! Conversely, if you are farther than 500 feet from that location, you could wave your golf club or umbrella high in the air, but you won’t draw the lightning away, even slightly, from striking where it’s going to strike. Steel does conduct electricity, but steel roofs don’t attract lightning or increase the probability of a lightning strike. Four factors affect the probability of a lightning strike: • Topography: a structure located on a mountain or hill has a higher probability of a strike than one in a field. • Structure size and height: a tall structure or one that covers a great deal of ground has a higher probability of a strike than a short or small building. • Relative location in relation to taller structures: a small, short building near a taller structure has a lower probability of strike than the taller structure. • Severity and frequency of thunderstorms in the structure’s vicinity. However, on occasion, lightning does strike a house. If your home were hit, the steel roofing would disperse the energy safely through the structure. Since steel roofing isn’t combustible or flammable, it’s a low risk and desirable roofing option where severe weather is concerned -- especially for lightning. For More Information For additional information on steel roofing or other sheet steel building products, visit our website at www.cssbi.ca.

Preface This How To Series publication is an educational tool intended to give guidance to anyone specifying sheetsteel building products. This particular publication deals with the retrofit of the building envelope utilizing sheet steel. This is a generic guide giving the basic details and should only supplement the specific recommendations or design guidance published by the manufacturer appropriate to their own products. The material presented in this publication has been prepared for the general information of the reader. While the material is believed to be technically correct and in accordance with recognized good practice at the time of publication, its should not be used without first securing competent advice with respect to its suitability for any specific application. Neither the Canadian Sheet Steel Building Institute norites Members warrant or assume liability for the suitability of the material for any general or particular use.

An independent assessment of the life cycle cost for various low slope roof systems revealed that steel roofing had the longest life span, no leaks due to material failures, and the lowest overall maintenance cost.

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.

PREFACE One of the objectives of the Canadian Sheet Steel Building Institute is the development of product standards to promote sound construction using safe building practices. This Standard is intended to further this objective by providing to buyers, manufacturers and installers of steel farm roofing and siding, information which can be used or adopted by reference where desired. The requirements contained herein are in accordance with accepted engineering principles, augmented by experience. They include recommendations covering steel thicknesses, minimum metallic coating designations, as well as design, manufacture and installation in general.

Introduction Sheet steel roofing and siding (cladding) is available in a wide variety of profiles, colours and paint systems. The modern prepainted systems used on Canadian-made products will provide decades of beautiful performance before there are any visible signs of deterioration of the paint surface. However, an important component of the cladding system is the fastener used to attach it to the structure. This fastener is not simply a screw; it is part of the roof or wall assembly and should be expected to provide the same long-term performance. This performance is not simply the capacity to safely hold the cladding in place, but also to match the colour and durability of the paint system. The selection of the correct screw for the job is the first step in the creation of a cladding system that will provide long-term performance. The next step is the installation. Installing screws in sheet steel cladding is commonplace and can be done very efficiently. The tool manufacturers have developed a wide range of options for installing fasteners into any type of substrate. Selecting the most appropriate tool will help the installation process.

Preface One of the objectives of the CSSBI and its members is the development of standards and technical publications that promote safety, performance and good practice. This "How To Series" of publications is an educational tool intended to give guidance to anyone specifying sheet steel building products. This particular publication is published as an aid to building owners as well as roofing and siding installers. It offers simple and practical recommendations for the selection, application and installation of light gauge steel cladding. This is a generic guide giving the basic details and should only supplement the specific recommendations or guidance published by the manufacturer appropriate to their own products. The views expressed in this guide are a collection of installation techniques and do not necessarily reflect those of all member companies of the CANADIAN SHEET STEEL BUILDING INSTITUTE. The material presented in this publication has been prepared for the general information of the reader. While the material is believed to be technically correct and in accordance with recognized good practice at the time of publication, it should not be used without first securing competent advice with respect to its suitability for any specific application. Neither the CANADIAN SHEET STEEL BUILDING INSTITUTE nor its Members warrant or assume liability for the suitability of this bulletin for any general or particular application.

It’s a fact that buildings consume two thirds of all the electricity produced in North America and one third of all the energy produced in North America. While it is recognized that cooling and heating costs can be reduced by adding insulation under the roof surface, there is a diminishing return on the strategy of increasing insulation to conserve energy costs. This is where “cool roofing” can play a role in further reducing the energy consumed, and in minimizing the Heat Island effect created in the big urban cities. Cool roofing relies on the properties of reflectivity and emissivity of the roofing material. Reflectivity Reflectivity is the ability of the roof to reflect solar radiation back into the atmosphere. Its primary measure is solar reflectance - the proportion of the total solar radiation that is reflected back to the atmosphere. Any solar radiation that is not reflected is absorbed into the building envelope, requiring further energy to cool the building; or partially convected into the atmosphere increasing the ambient air temperature in the surrounding environment (Heat Island effect). The measure of reflectivity is the Solar Reflectance Index (SRI) which takes into account the properties of the material as well as the cooling effect of wind passing over the roof. The SRI for a low slope roof will be 0 for standard black (reflectance 0.05, emittance 0.90) and 100 for standard white (reflectance 0.80, emittance 0.90).

PREFACE One of the objectives of the Canadian Sheet Steel Building Institute is the development of product standards to promote safety and sound construction practices. This Standard is intended to assist specifiers, designers, buyers, manufacturers, and erectors of sheet steel cladding by providing information which can be adopted by reference where desired. The requirements contained herein are in accordance with sound engineering principles, augmented by experience. They include recommended minimum requirements for such factors as grade of steel, thickness, metallic coating designation, loading and deflections, as well as design, fabrication and erection in general. While the material is believed to be technically correct and in accordance with recognized practice at the time of publication it does not obviate the need to determine its suitability for a given situation. Neither the Canadian Sheet Steel Building Institute nor its members warrant or assume liability for the suitability of the material for any general or particular application. 

For BART's Doolittle Maintenance Facility at the new Oakland Airport connector, SAFTI FIRST® provided 60 minute, fire resistive wall openings in the exterior using SuperLite® II-XL 60 insulated with low-e glazing in GPX® Framing with a clear anodized finish. SAFTI FIRST® engineered a connection that allows the structural elements of the GPX® Architectural Series Framing System to support an integral sunshade system, instead of being hung in front of it. The Doolittle Bart Station is one of the first installations of the GPX® Architectural Series System with sunshade connections, which also include SLCC New Instruction and Administrative Building in Salt Lake City, UT.

The west-facing elevation of The Kensington in Boston, MA, was in close proximity to the property line, prompting the building official to require part of the curtain wall had to meet ASTM E-119/NFPA 251/UL263 for 60 minutes. SAFTI FIRST® supplied SuperLite® II-XL 60 insulated with Solarban 70XL in GPX® Curtain Wall Framing in a continuous span from the seventh to the tenth floors.

We built the world first Passivhaus CPD training facility / pub, this is the worlds most airtight pub at 0.07ach at 50 pa. This is a twin wall timber frame, it’s 450mm wide insulation Huntsman which is made of thousands of recycled plastic bottles. Huntsman also recycled 1 billion plastic bottles from the sea last year. We have a 7.2 KW system solar panels system that powers the building, it’s got MVHR Nilan. On the external façade we applied Passive Purple External which is airtight up to 0.03ach.

Designed by Pritzker prize winning architect Shigeru Ban, the brand new 33,000 sf Aspen Art Museum boasts large exterior glass walls designed to keep the visitors engaged with views of the beautiful Aspen landscape. SAFTI FIRST®’s engineering team provided design assistance and supplied a 2 hour fire resistive curtain wall with SuperLite® II-XL 120 with Starphire Ultra-Clear Glass insulated with Viracon VE13-85 in GPX® Curtain Wall Framing. A woven screen encloses the glass curtain wall to provide shading from direct sunlight.

Introduction Prefinished sheet steel is used on many building products from wall cladding, to architectural roofing to interior panels. Prefinished sheet steel has been used in Canada for over 30 years and there may be sites were the paint surface is in need of repainting. This bulletin is intended to give some guidance on repainting prefinished panels. Due to the diversity of factory applied prefinished systems, and the diversity of potential field applied repaint systems, it is impossible to offer one comprehensive repaint procedure for all possible situations. However, it is possible to offer a set of guidelines to be considered in every potential situation.

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.

An old block of apartments in Gt. Yarmouth getting a low carbon Retrofit for a higher, cleaner living standard and reduced energy bills. Passive Purple has been used externally on this huge scale block of apartments. with no margin for error and tricky details throughout, a liquid applied airtight membrane was the only way going forward. The building was being insulated externally and getting a whole new façade from render to aluminium panels. With the residents still inhabiting the building this had to be done quickly and easily with maximum results. Being a liquid applied airtight membrane, any cracks, gaps, and service penetration leaks in the existing building fabric quickly became thing of the past. That and the hundreds of Panel brackets being installed to support the new façade going on, this Retrofit had multiple penetrations and tricky details. Making good of the building fabric and awkward brackets with a near on impenetrable adhesion, Passive Purple made fast work of this great conversion, impossible for any other method. Being in liquid state on application, Passive Purple can be applied onto most/any surface (See data sheets for more information) and will find its way into all the unseeable tiny gaps and cracks all buildings will undoubtably have. Like this old pebble dashed façade, any rough, uneven and awkward areas are no longer an issue, our products simply flow into these areas. We also have the fibre reinforced Passive Purple brush, used on this job to prepare the brackets by filling the larger gaps between that of the bracket and the existing wall and also the large penetrating bolts. A huge win and demonstration of the power of liquid products by Intelligent Membranes.

Introduction Prefinished sheet steel building products, such as wall and roof cladding, liner sheet, flashing, and associated items, have experienced an enviable growth record during the past twenty years or so. Coil coated prefinished sheet steel in a variety of colours and paint systems has greatly enhanced the appearance of thousands of industrial, commercial, institutional, recreational, residential and farm buildings, providing an economical, durable and attractive alternative to traditional materials. As with all materials, a little care and maintenance pays off handsomely in terms of longevity and repair costs. The recommendations which follow have been learned at first hand and represent the collective industry experience with thin-film paint systems applied to metallic coated sheet steel by the coil coating process. In this publication the term “thin-film paint system” refers to a modified silicone polyester or a fluorocarbon type having a coating thickness about 25µm. When the guidelines listed below have been observed, thin-film paint systems have been used successfully for all types of environments other than severe industrial atmospheres which require special consideration. The guidelines are not intended for barrier coatings, laminates, and new formulations which have different characteristics than the thin-film paint systems on which these guidelines are predicated.