Design, Detail and Colour Considerations
Here are some things to take into consideration when choosing the details, design and colors for your metal product.
- Architectural details should permit natural rain- flow cleaning of the cladding.
- On roofs or other horizontal surfaces, standing water can contribute to the premature failure of the paint system and substrate. Detailing should preclude damming or ponding of rain-flow at stacks, ventilators, air control equipment and other objects.
- Due to colour tolerances, there may be differences in colour shade between production runs. Where possible, ensure that each building elevation is clad with material from the same production lot. If different production lots must be used on one elevation, as may occur when making an addition to an existing building, try to begin the cladding on an elevation change or break in the building to minimize the effect of possible colour variations.
- A sufficient roof slope to permit drainage is recommended (e.g. minimum slope 2/12 pitch).
- Roof surfaces, defined as those up to 60 degrees from the horizontal, are subject to more severe exposure conditions than vertical surfaces. Conditions such as extended exposure to ultraviolet light may be resisted by using a light colour for the roof. Acid precipitation and drip edge puddling are other conditions that could affect the appearances and durability of the paint finish. Drip edge puddling may be minimized with a steeper roof slope or by modifying the edge details. If severe acid precipitation is experienced, a more resistant pre finish system may be required.
- The building design should seek to minimize the installation of mechanical equipment on a pre finished roof. Walkways should be provided where regular traffic is necessary for maintenance.
- In wall applications, horizontal portions of the cladding and base flashing should be sloped to prevent moisture from puddling.
- Walls shadowed by overhangs and all soffit areas have an increased time of wetness relative to other areas. The increased time of wetness creates a more aggressive environment for the cladding so affected; therefore, architectural details should try to minimize these areas.
- To decrease the visibility of “oil canning”, select an adequate material thickness, a narrower flute and a lighter colour.
- To prevent unwanted galvanic corrosion, the architectural details should not allow the contact of dissimilar metals (e.g. steel and aluminum or copper) or should provide an adequate means of separation. The path of rainfall runoff should also be directed to prevent water runoff across one type of material to another which can also cause galvanic corrosion.