Metal roofing is incredibly durable but it isn’t indestructible. Exposed as it is to the elements, it can weather and age. Some components will not last as long as others and sometimes things just happen, like softball sized hail or 60 mph winds blowing sand across the finish.
You don’t need to do much maintenance on your metal roof but you do need to keep up with wear and tear, storm damage, and simple shifting. Here is what you need to do to keep your metal roof, and the rest of the building, in tip-top shape.
At least twice a year as well as after every severe weather event, you will want to inspect your metal roof for distress conditions. As you begin, make certain you or your inspector only walk directly over joists and purlins to avoid further damage to the roof panels.
Check for the following:
- Movement distress in panels and fasteners
- Sealant failures
- Damage from snow, ice, or hail
- Aging or missing fastener gaskets
- Debris and clogs in the drains and gutters
- Surface coating failures
- Any rust or corrosion
To look for movement distress in fasteners, check all screws and fasteners to make sure they are still tight. Movement can make screws back out of the hole. You will see the screw and possibly some threads sticking up above the level of the gasket or roof panel.
Sealant failures can be seen in peeling or flaking sealant, discolored sealant, and around fasteners that have come loose. Many sealants only last 20 years or so but can become damaged from roof panel and fastener movement. Plus, there is always the possibility a critter thinks it tastes good.
Damage from snow and ice often reveals itself as ice dams and leakage under the roof. If the roof slope is low, the accumulation of snow or ice can cause panels to buckle. Hail, of course, can leave dents or, in the event of very large hailstones, can create holes in the panel.
Fastener gaskets have limited lifetimes. Check the manufacturer’s specifications for replacement schedules. Otherwise, check for tightness, discoloration or corrosion, and breakage.
Over time, debris can be washed off the roof and into any gutter system you may have installed. If the drain or gutter becomes clogged, water may accumulate and back-up onto the roof creating conditions for corrosion. Be careful not to scratch any coating or sealant when removing branches or other debris.
Finally, look for scratches and peeling surface coatings. Protective coating failures provide opportunities for corrosion and rust to form on the bare metal.
Once you have inspected the roof and you need to repair any damage you found.
Expansion and contraction in the heat and cold causes panels to shift. Sometimes this results in a separated seam or holes where fasteners have popped loose. It is also possible that fasteners and gaskets have broken in the movement or because of hail and ice damage.
Replace any missing fasteners and gaskets using components of the same metal as the roof panels. Allowing different types of metals to touch can create another chance for corrosion or discoloration. Seal each replacement fastener and panel seam with recommended sealant.
When you place screws always use washers or gaskets and never place them in a low-lying area where water can pool.
Small holes can be repaired with small amounts of roof cement while large ones can be covered with a patch of the same metal soldered into place. Be sure to seal the cut edges of the patch so it won’t rust. If you have a very large area of rust or corrosion, you may need to replace the entire panel. Since metal building systems are manufactured to work as a unit, try to obtain a panel that is specific for your building style from the same vendor you got the building system from.
If you find any bare metal due to scratches or other damage, touch it up with paint or other sealer before rust can occur. Metal edges may have the paint or sealant worn away and require touching up.
Fastener gaskets have a limited lifetime and must be replaced on a regular basis. Check the manufacturer’s specifications for a replacement schedule. Again, make sure to use fasteners and gaskets made of the same metal as the panels and seal each one as you replace it.
Most sealants are only good for 20 years and should be removed and replaced on a regular schedule as well. As you replace gaskets or make repairs and replacements for missing fasteners, make sure to seal each one as you go.
Coatings are like sealants. They are exposed to the environment and act as protection for the metal. Coatings age and may peel or simply lose their protective ability. Talk to a roofing specialist to determine the best protective coating for your roof.
If your building has been exposed to extremely harsh conditions or has been without maintenance for a time, you would do well to reseal all the seams and fasteners, with particular attention to areas where the seams appear to be opening and in areas where multiple pieces of hardware were replaced.
All metal surfaces require protection. So nothing gets missed (tiny scratches, invisible openings near fasteners, and the like) you will probably need to repaint the entire roof every so often as the coating ages. Maybe you would like a new color; this would be a good time to change it.
Make it last
No, a metal roof isn’t indestructible, but it’s the next best thing to it. Twice yearly inspections, tender loving care after big storms or harsh seasons will help you find and make repairs before a small problem becomes a big problem.
You have to remember, also, that the roof isn’t entirely made of steel. Components such as sealants and gaskets age and require periodic replacement. By making these repairs and replacements, along with a new coat of protective paint, you can help your metal roof keep the weather off you and your stuff for decades.