Page 3 - Westform Public Catalogue 08-06-24

CARE AND MAINTENANCE

OF PREFINISHED SHEET STEEL PRODUCTS

May, 2024

INTRODUCTION • A sufficient roof slope to permit drainage is recommended (e.g.

Prefinished sheet steel building products, such as wall and 1 in 48 minimum, and greater where rainfall is heavy, drainage
roof cladding, liner sheet, flashing, and associated items, have is restricted, etc.).
experienced an enviable growth record over the past twenty years. • Roof surfaces, defined as those up to 60 degrees from the
Coil coated prefinished sheet steel in a variety of colors and paint horizontal, are subject to more severe exposure conditions
systems has greatly enhanced the appearance of thousands of than vertical surfaces. Conditions such as extended exposure
industrial, commercial, institutional, recreational, residential, and to ultraviolet light may be resisted by using a light color for
farm buildings; providing an economical, durable and attractive the roof. Acid precipitation and drip edge puddling are other
alternative to traditional materials. As with all materials, a little conditions that could affect the appearances and durability of
care and maintenance pays off handsomely in terms of longevity the paint finish. Drip edge puddling may be minimized with a
and repair costs. The recommendations which follow have been steeper roof slope or by modifying the edge details. If severe
learned first hand and represent the collective industry experience acid precipitation is experienced, a more resistant prefinished
with thin-film paint systems applied to metallic coated sheet system may be required.
steel by the coil coating process. In this publication the term • The building design should seek to minimize the installation of
“thin-film paint system” refers to a modified silicone polyester or mechanical equipment on a prefinished roof. Walkways should
a fluorocarbon type having a coating thickness about 25um. be provided where regular traffic is necessary for maintenance.
In wall applications, horizontal portions of the cladding and
When the guidelines listed below have been observed, thin- base flashing should be sloped to prevent moisture from
film paint systems have been used successfully for all types of puddling.
environments other than severe industrial atmospheres which • Walls shadowed by overhangs and all soffit areas have an
require special consideration. The guidelines are not intended increased time of wetness relative to other areas. The increased
for barrier coatings, laminates, and new formulations which time of wetness creates a more aggressive environment for the
have different characteristics than the thin-film paint systems on cladding affected so; therefore, architectural details should try
which these guidelines are predicated. to minimize these areas.
• To decrease the visibility of “oil canning”, select an adequate
DESIGN, DETAIL & COLOR CONSIDERATIONS material thickness, a narrower flute and a lighter color.
• Architectural details should permit natural rain-flow cleaning • To prevent unwanted galvanic corrosion, the architectural
of the cladding. details should not allow the contact of dissimilar metals (e.g.
• On roofs or other horizontal surfaces, standing water can steel and aluminum or copper) or should provide an adequate
contribute to the premature failure of the paint system and means of separation. The path of rainfall runoff should also be
substrate. Detailing should preclude damming or ponding of directed to prevent water runoff across one type of material to
rain-flow at stacks, ventilators, air control equipment and other another which can also cause galvanic corrosion.
objects.
• Due to color tolerances, there may be differences in color SITE STORAGE
shade between production runs. Where possible, ensure that • Storage time should be minimized by installing the cladding
each building elevation is clad with material from the same panels as soon as possible after delivery. Good planning will
production lot. If different production lots must be used on one ensure that panels are used on a first-in first-out basis.
elevation, as may occur when making an addition to an existing • If cladding must be stored for an extended period, the most
building, try to begin the cladding on an elevation change or desirable storage place is under-roof in a cool, dry, well
break in the building to minimize the effect of possible color ventilated area.
variations.