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Galvalume® Steel Roofing: Good Practices Guide

Maintenance Guarantees Satisfaction For Building Owners

Minimum maintenance of GALVALUME steel roofing is required. The roof should be inspected at least once a year. Any exposed metal that can rust or has rusted should be painted. Leaves, branches, and trash should be removed from gutters, at ridge caps and in corners. Also watch out for discharge from industrial stacks, and particulate matter and high sulfur exhaust from space heaters.

Roof-top ancillaries and air conditioner supports, drains and housings should be checked. Particular attention should be paid to add-on roof ancillaries that create new roof penetrations. Roof-top air conditioners should be installed on GALVALUME curbs designed to avoid ponding water.

Lighter gauge, low slope screw down roofs are susceptible to panel walk-down. As a precaution, workmen should walk on panel areas supported by purlins. Walk-down is generally not a problem on standing seam roofs with a 1/4:12 slope when 0.024-inch thick and heavier panels are used with 5' or less purlin spacing.

Class Lighter Gauge

This 0.022-inch thick screw down roof has a 1/4:12 slope; heavy foot traffic during installation and maintenance caused panels to deflect permanently between the purlins and collect water.


Condensate from air conditioning and refrigeration equipment should never be allowed to drain directly onto the roof panels. The drainage contains copper ions from condenser coils that accelerate corrosion.

In the event of a roof leak, do not indiscriminately plaster the suspected leak area with tar or asphalt or use repair tape. Water can collect under the repair material, causing corrosion. Instead, have an experienced metal roofing contractor locate the leak, identify its cause, and properly repair the roof.

All rooftop equipment should be installed so that water can drain around it. Manufactured curbs and flashings, when used as recommended, will ensure proper drainage.

The air conditioneron this roof is installed using a manufactured curb. Water easily drains around the unit and off the roof.


Do not indiscriminately apply roof repair materials at suspected leak areas. Instead, have an experienced metal roofing contractor locate the leak, identify its cause, and properly repair the roof.

Here is an example of a leak improperly repaired with repair tape on the outside. Water trapped under the repairs caused severe corrosion and rusting.


Condensate from rooftop air conditioners should be discharged through a plastic pipe extended to a rain gutter or vent pipe, but preferably to the ground. The condensate contains dissolved copper from contact with the condensation coils and can cause rapid corrosion if discharged on the roof panels.

Air conditioner condensate is discharged by a plastic tube into a plumbing vent pipe, eliminating drainage and corrosion problems.

On this good-condition 20-year-old roof, condensate from HVAC unit is causing premature rusting of the galvanized curb and the GALVALUME panel.