Oil-Canning: Specifying Wide Flat Panels in Metal Cladding

This post is intended to inform building designers, architects, specifiers and owners on the phenomenon called "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 profile. 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 well aware of the potential for oil-canning in their cladding profiles. It is important for the proper steps to be taken during manufacturing to produce a quality 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 minimized if the following factors are considered.

Sheet Thickness: The thicker the sheet, the flatter the profile can be maintained.

Flat Width: The narrower the flat width of the cladding element, the harder it will be for that area to develop into the noticeable oil-canning waves.

Temperature: The expansion and contraction of the cladding sheet due to changes in temperature creates stresses which will exaggerate oil-canning. 

Cladding Orientation: Cladding profiles can be installed both vertically and horizontally to achieve

different architectural effects. The appearance of oil-canning in a vertical application is less pronounced than in a horizontal application due to the different way the eye of the observer perceives the standing waves.

Paint System: The nature of the paint system selected for the cladding is a strong contributor to controlling the visual impact of oil-canning. Textured finishes in lighter colours will reduce the visibility of oil-canning where the identical cladding in a darker colour with a smooth finish will highlight any irregularities.

Cladding Slope: The slope of the wall or roof on which the cladding is mounted will affect the visibility of oil-canning by changing the angle of incidence of the reflected light. 

Handling: Carrying of panels in the flat, or twisting of the panels during lifting, can induce a wavy appearance to a previously flat panel.

Installation: Over-engagement of the cladding panel and over-driving of fasteners are two installation related factors which can contribute to oil-canning. 

Erection Tolerances: Out-of-straightness of the structural supporting members will increase oil-canning by inducing bending stresses into the profile. 

To learn more about oil-canning and how to prevent it, download Fact Sheet 13: Position Paper on Oil-Canning: Specifying Wide Flat Panels in Metal Cladding

Revêtement de tôle d'acier préfini: Coûts

Ce qui suit sont quelques facteurs qui modifient le coût des produits de revêtement en tôle d'acier préfini. La couleur, le système de peinture, la quantité commandée, l'inventaire du fabricant et le choix du profilé sont les facteurs les plus importants. La connaissance de l'impact de ces facteurs sur les coûts peut vous aider à sélectionner un système de revêtement répondant aux exigences de durabilité et d'esthétique de votre projet, tout en restant dans les limites d'un budget.

Couleur
La couleur est probablement l'un des facteurs les plus importants lors de la sélection d'un revêtement de tôle d'acier. Pour être plus compétitif et améliorer le service à la clientèle, la structure de prix des produits de tôle d'acier préfini est maintenant basée sur un système de "prix par couleur". Il est important de savoir que les prix peuvent varier considérablement d'une couleur à l'autre.

Système de peinture
En plus du choix de couleur, il est important de savoir que différents systèmes de peinture peuvent offrir la même couleur. Les systèmes de peinture les plus populaires au Canada actuellement sont la série Perspectra, la série 10 000 et la série Barrière. Chaque système répond à des critères de performance distincts et offre une durée de vie différente.

Quantité commandée
La quantité de tôle d'acier préfini nécessaire pour effectuer un projet influence également les coûts totaux. En général, les coûts à l'unité sont plus élevés pour les petites quantités de matériaux qui ne sont pas vendus régulièrement. Ces coûts reflètent le coût plus élevé de l'acier acheté en petites quantités, les exigences minimales concernant la commande d'acier sur bobines et les coûts de préparation du fabricant.

Inventaire des fabricants
La disponibilité de la couleur choisie dans l'inventaire du fabricant peut aussi faire varier les coûts. Un fabricant ne possède pas en stock toutes les couleurs et tous les systèmes de peinture, mais il peut répondre à une demande particulière.

Choix du profilé
En plus des variations de prix de la tôle d'acier préfini ordinaire, il existe également un vaste choix de profilés et de systèmes de revêtements muraux. Les systèmes de revêtements varient du panneau architectural à attaches dissimulées (plus dispendieux), au panneau ondulé à cannelures peu profondes (économique).

Cost Considerations for Prepainted Sheet Steel Cladding

The following are some of the factors that affect the cost of prepainted sheet steel cladding products. The most significant factors are: colour, paint system, order quantity, Fabricator's inventory and profile selection. Recognition of the impact of these factors can help you select a prepainted sheet steel cladding system to fit the aesthetic and durability requirements of your project, and still stay within a budget.

Colour
Probably one of the most important considerations for your prepainted steel cladding selection is colour. In a move at being more competitive, while offering effective customer service, the pricing structure for prepainted sheet steel is now based on a "price by colour" system. It is important to recognize that prices can vary considerably from one colour to another.

Paint System
Colour selection is important, but it is also important to realize that the same colour may be available in different paint systems. Currently, the most common paint systems in Canada are the Perspectra Series™, 10 000 Series and Barrier Series. Each of these paint systems meets a different performance specification and have different expected service lives. The nature of the environment will determine the proper selection of the paint system.

Order Quantity
The amount of prepainted sheet steel product needed for the job will also affect the project costs. Normally costs are higher, on a per unit basis, for smaller order quantities that are not normally
stocked. These costs reflect the higher cost for steel being purchased in smaller quantities, minimum steel coil order requirements, and the set-up costs for the manufacturer.

Fabricators Inventory
The availability of your colour selection in the Fabricator's inventory will also create cost variations. A Fabricator does not stock all colours and paint systems, but will inventory a selection.

Profile Selection
In addition to the variations in the cost of the basic prepainted sheet steel, there is a wide range of panel profiles and cladding systems also available. Cladding systems range from the more expensive architectural concealed fastener panels to the economical shallow ribbed corrugated sheeting.

To read more about cost considerations for prepainted sheets steel cladding, download out Fact Sheet 1 - Cost Considerations for Prepainted Sheet Steel Cladding.

Season's Greetings - Joyeuses fêtes

 

Toiture en acier - plusieurs styles

Il existe plusieurs couleurs et plusieurs styles de nervures verticales, de joints debout, bardeaux d'acier et de profilés de tuiles qui rehaussent tous les types de maisons. La seule difficulté consiste à décider quel modèle convient le mieux à votre maison.

Profilés à nervures verticales

Une tôle d’acier profilée est fixée à la structure portante à l’aide de vis à travers les nervures de la tôle. Les têtes de vis peuvent être peintes de la même couleur que la tôle. Les panneaux sont habituellement d’une largeur de 30 pouces ou plus et leur longueur peut être spécifiée selon l’application. Ce type de système de toiture en acier est très populaire pour de nombreuses applications au Canada.

Profilés à motif en tuiles

Panneaux d’acier prépeints profilés pour ressembler aux tuiles d’argile ou de béton souvent utilisées dans les constructions résidentielles. Le grand choix de largeurs et de longueurs élimine les nombreux joints que requièrent les toitures en tuiles d’argile ou de béton. De plus, leur poids plus léger permet de préserver la structure du toit. De nombreuses textures et couleurs sont offertes.

Toit à joints scellés
Ce type de toiture se caractérise par son motif d’ombres linéaires. Une grande variété d’espacements et de modèles de nervures et de joints scellés est offerte. Ces joints peuvent être plats ou cachés, ou en lattis larges. Les design et les systèmes d’ancrage varient d’un fabricant à l’autre. La hauteur et la largeur des joints scellés, de même que leurs couleurs sont très variées, permettant ainsi de satisfaire tous les goûts.

Bardeaux d'acier

Les bardeaux d’acier ont été conçus comme alternative aux bardeaux d’asphalte communs, mais avec la résistance et la longévité des panneaux de toiture en acier. Les bardeaux d’acier sont plus légers que les bardeaux de toiture en asphalte, en cèdre et en ardoise et que les tuiles de béton et d’argile. Ils ne pourrissent pas, ne gondolent pas, ne se fendillent pas, ne se déchirent pas, ne s’écorchent pas, ne pèlent pas et ne se perforent pas dans des conditions d’usure normales et avec un minimum d’entretien.

La source principale des propriétaires de maison canadiens à propos des nombreux avantages des toitures résidentielles en acier. Regardez les styles et les couleurs variés. Figurez-vous comment un toit en acier changera l’apparence de votre résidence tout en vous donnant une valeur pour la vie. Visiter SteelRoofSource.com

 

The Many Styles of Residential Steel Roofing

There are several styles and colours of vertical rib, standing seam, steel shingle and tile profile that complement any style home. The only difficulty is deciding which one is best for your home!

Vertical Rib Formed Roofing

A profiled steel sheet is fastened to the supporting structure with screws through the ribs of the sheet. These screws can have heads painted to match the colour of the sheet to blend in. Panel widths are typically about 30 inches wide or greater and can be supplied in custom lengths to fit the application. This type of steel roofing system is very popular in many applications all across Canada.

Tile Design Roofing

Pre-painted steel panels formed to create the appearance of clay or concrete tiles are often used in residential construction. The wide sheet widths and long lengths eliminate the many joints found in clay and concrete tile roofs. In addition, their reduced weight spells savings in the roof structure. There is a wide variety of colours and textures available.

Standing Seam Roofing

These designs are characterized by their linear shadow patterns. They vary greatly in the spacing and the design of the ribs or standing seams. These seams vary from flat, hidden seams to wide battens. There is a variety among manufacturers as to the design and the anchoring systems. The height and width of these standing ribs, as well as their colour will express a broad spectrum of aesthetic expressions.

Steel Shingles

Steel shingles are designed as an alternative to common asphalt shingles, but with toughness and long-lasting qualities of high-strength steel roofing panels. They are lighter than asphalt shingles, concrete and clay tiles, cedar shakes and slate roofing. Steel shingles will not rot, curl, crack, break, chip, peel or perforate under normal use and minimal maintenance. There is a wide variety of colours and textures available.

If you are looking for more information about residential steel roofing, please visit our website dedicated to the topic. www.steelroofsource.com

Sheet Steel Gauges - What They Mean

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Introduction

Within the construction industry there is often confusion over gauges, gauge numbers and the related thickness. The industry has been trying to move away from gauge numbers, without complete success. The following information will show why sheet steel products should be specified to the decimal thickness.

Manufacturers’ Standard Gauge For Steel Sheets

The most common gauge system used in Canada for structural sheet steel products is the Manufacturers’ Standard Gauge (MSG). The MSG for steel sheets was developed having a DEFINITE THICKNESS equivalent for each gauge number. In the standard gauge system the density of steel is taken as 489.6 lbs/ft3, or 40.80 lbs/ft2/in. However, since sheet weights are calculated on the basis of specified width and length, with all shearing on the over side, and also since sheets are somewhat thicker at the centre than they are at the edges, a further adjustment was made to obtain a closer approximation for inter-changeability between weight and thickness. Over a long period of time this value for sheets has been found to be close to 2.5 per cent heavier than 40.80 lb/ft2/in. A figure of 41.820 lb/ft2/in is the one commonly used to express the relationship between weight and thickness for steel sheet.

The Galvanized Sheet Gauge

The Galvanized Sheet Gauge is an older system used primarily by the trades consuming non-structural galvanized steel and is a measure of the zinc coated sheet thickness. It was developed in the early days of galvanizing before sophisticated wipers were available and, consequently, zinc thicknesses were thicker than today. The GSG system was used on some of the older gauge charts published years ago that unfortunately still seem to get used even today.

Thickness Definitions

There are a number of terms used for sheet steel products that need to be explained because they will affect the thickness of product that could be delivered to the job site.

Nominal Thickness: When sheet steel is produced by the steel companies it is manufactured to a target or “nominal” thickness. As with all manufacturing processes, variations in the final thickness of the sheet are unavoidable. However, the thickness is controlled very tightly to ensure that it does not fall below the minimum thickness (as described below).

Base Steel Thickness: The thickness of the sheet steel material without any coatings.

Coated Thickness: The thickness of the steel sheet including any metallic coatings (i.e. zinc or aluminum-zinc alloy) and paint coatings.

Design Thickness: The design thickness is the thickness of the base steel only, and is used by the engineer to determine the structural properties of the cold formed product. This is the thickness that a manufacturer will list in their product catalogues and load tables.

Minimum Thickness: The minimum thickness of structural sheet steel building products delivered to the job site will be the design thickness minus the maximum allowable under-tolerance specified by the CSA-S136 Standard or the material specification, whichever is the more restrictive. The minimum thickness allowed by the CSA-S136 Standard is 95% of the design thickness.

Click to download Fact Sheet 10: Sheet Steel Gauges and Thicknesses to see Tables detailing the various gauges of sheet steel and their thicknesses.