How to Prevent Ice Dams on Metal Roofs

Those in areas prone to below-freezing temperatures are likely familiar with ice dams and the costly damage they can cause. With winter weather already upon us, it’s important to ensure your building is protected against the dangerous and expensive effects of ice dams.

What Causes Ice Dams to Develop?

Most ice dams are a result of building air barrier flaws. When warm indoor air escapes through a rooftop, it warms the roof sheathing. This rise in temperature melts the underside of the layer of snow on top. The melted snow then moves down the slope of the roof toward the eaves, where it freezes into ice. As this process continues, the ice thickens, resulting in ice dams. These obstructions can cause water to back up and form a reservoir that can damage ceilings.

Ice Dams | ABC Blog

How Can Ice Dams Be Prevented?

To prevent ice dams, follow these four steps:

  1. Seal Air Leaks: Sealing air leaks between the warm building interior and the attic or ceiling is imperative to prevent increased sheathing temperatures that can lead to ice dams. If your roof leaks every winter, it’s likely that an air leak is to blame. And, getting a new roof is not likely to help—even if it features more ventilation. The simple way to determine if you have air leaks is to get into your attic and check. Leaks can likely be easily sealed with two-component polyurethane spray foam. And extending any exhaust fans that don’t reach outside can help adequately seal the structure.
  1. Ensure Proper Insulation: Many buildings don’t have adequate insulation levels to prevent ice damming. Building codes based on your geographic location can help you determine how much insulation you need. If the structure’s design doesn’t allow for adequate insulation, we recommend installing as much closed-cell spray polyurethane foam as possible. If replacing your roof, you can also install additional rigid foam insulation on top of the existing roof sheathing before you install the new roof. When taking that approach, make sure all products used are compatible with your new roof and adhere to manufacturer’s recommendations. It’s also imperative that attic insulation completely covers the top plates of a building’s exterior walls.
  1. Improve Ventilation: Improving ventilation alone will not prevent air leaks that cause ice damming and should never be your first or only defense. In fact, improving ventilation without sealing air leaks and installing adequate insulation can increase heating costs and make ice damming problems worse. Despite this, if combined with steps one and two above, addressing your roof ventilation can’t hurt. The best ventilation options include soffit and ridge vents. It’s important to remember that all attic ventilation systems require an insulation dam (blocking) between the trusses and ventilation baffles at the attic’s perimeter, facing the soffits, to maintain a ventilation channel from the soffit to the attic and protect against wind-wash.
  1. Use Underlayment: Covering your roof sheathing with two or more layers of rubberized membrane underlayment is another protection method that is far less effective if not used in concert with steps one and two. To use properly, it should extend from roof eaves to a point that’s three feet higher than your exterior wall.

Additional measures like framing your roof with raised-heel trusses can also help prevent ice dams. Additionally, avoiding including valleys as well as gutters that are at or above the roofing plane is ideal. Taking these steps can help ensure people and property are safe from overhead dangers. This should be a priority when designing, installing and maintaining your metal roof.

For additional information on how metal roofs perform in winter weather, read part one and part two of our ‘Metal Roofs and Snow’ blog series. For additional tips on how to winter-proof your roof, reach out to a local ABC representative today.

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Maintaining, Cleaning & Repairing Metal Panels

Understanding the maintenance requirements of your metal panels is essential to maximizing the longevity of your investment with the least amount of hassle. While metal panels have been engineered to provide decades of trouble-free protection, they can suffer damage from the build-up of debris as well as storm-related traumas like hail stones, falling branches and ice dams. To extend the lifespan and strength of metal panels, maintenance consists mostly of preventing and correcting these issues.

metal roofing maintenance tips

 The importance of regular inspections

Regular inspections are critical to identifying damaged panels and accumulated debris that can trap moisture, causing corrosion over time. To prevent this, a visual inspection should be performed in the spring and the fall of each year, as well as after major weather events to identify issues. Take a walk around the structure and look for leaves, branches and other debris piled up on the roof, including in valleys, gutters and downspouts, as well as behind chimneys and/or other protrusions. While you can perform this type of inspection yourself, please keep in mind that metal panels—particularly metal roofs—should be professionally inspected every four to five years depending on your geographic location. If you live in a coastal or humid area more prone to corrosion and rust, professional inspections should be done more frequently to prevent the rust from spreading and causing structural damage to the panels.

In addition to debris, keep an eye out for scratched or dented areas, as well as for loose screws and seams that look like they are separating. (If you can’t make out the details from the ground, try using a pair of binoculars.). Use the manufacturer’s recommended touch-up paint to correct scratches as they can quickly degrade the surface protection and jeopardize the longevity of metal panels. If the panels have separating seams or holes, first check to see if the repair is partly or fully covered by your warranty. Unless you are experienced in metal roof repair and possess a thorough knowledge of the products and techniques that can be used without voiding the warranty, it is recommended that you engage a metal panel repair specialist to make the repairs. If you decide to undertake the work yourself, it is also important to remember that these fixes are, at best, temporary and should be addressed by a professional recommended by the metal panel manufacturer.

Cleaning metal panels

Keeping metal panels clean is one of the best ways to ensure they last as long as possible. When cleaning metal roofs and walls, using a non-pressure cleaning method with detergents recommended by the metal panel manufacturer is ideal. It is not advisable to use metal tools such as rakes to remove debris. This is likely to scratch the paint, reducing the panels protection from the elements and other damaging factors. Using a leaf blower to remove debris is a common choice, but a long-handled push-broom or a telescoping pole with a window cleaning brush will also do the job. Ideally, the tool should be one that lets you do the removal from the ground, but if you absolutely must walk on the roof then only step on the flat areas. If there are areas you can’t access yourself—particularly slanted areas that have been made slippery with cleaning solutions—hiring a professional service to do this once or twice a year is the safest option.

To reduce the chance of further damage and keep your panels cleaner over longer periods of time, trim tree branches as far back from the building as possible. This is especially important for large, unhealthy branches that could break off during high winds and cause damage.

Proper snow removal

There are—of course—considerations that must be made for metal buildings located in colder climates. After a winter storm, it’s a good idea to remove standing snow from the roof. This is doubly important on older homes where poor attic insulation can lead to ice dams. An ice dam forms when heat escaping from inside the attic warms the roof and melts the bottom layer of snow. The snowmelt then re-freezes, creating a dam that traps water which can work its way into seams between panels and around flashings.

Warranty considerations

It’s always smart to reference the metal panel manufacturer’s warranty to be sure you don’t use any products or tools that will void your warranty. They should also provide instructions and advice specific to the panels and application(s) you’ve selected to ensure you get the most out of their products with the least hassle.

For more information on metal panels, check out ABC’s FAQ page. For more on our metal panels and accessories, please visit our product pages or contact your local representative today.