Many homeowners ask this question when considering metal roofing versus asphalt shingles: Are metal roofs noisy when it rains? The short answer is not necessarily. The perception that metal roofing is loud most likely comes from standing in a barn or shed when it’s raining. This comes down the roofing installation methods, which differ from residential and commercial construction to agricultural construction. The truth is that high quality metal roofing that is properly installed shouldn’t be louder than traditional asphalt shingles.
With traditional roofing installation, plywood decking, insulation and underlayment are used to add protection and reduce noise. The plywood decking or sheathing layer is installed first. Next, the underlayment is added, serving as a moisture barrier. Finally, add insulation in the attic airspace below.
Without these elements of a traditionally installed roof, the metal panels are installed directly on the framing. This means that there’s no barrier to reduce noise transfer to the interior of the building. This is common in secondary structures such as barns, sheds and other agricultural structures.
Tips to Reduce Metal Roof Noise
If your metal roof was installed without plywood decking, underlayment and insulation, here are some tips to reduce metal roof noise:
1) Add Insulation – Insulation serves as an acoustic barrier and reduces noise transfer to the interior of your building. It also improves the energy efficiency of your building, helping to reduce overall energy costs.
2) Properly Fasten Roof Panels – Proper installation is crucial to reducing noise. Use proper fasteners and don’t over or under-tighten them. Refer to the product manual for correct fastener layouts and spacing.
3) Replace Your Roof – Consider replacing your roof and using traditional methods for residential and commercial roofing installation. Insulated metal panels are also a great option as they provide thermal, moisture and vapor barriers in a single component.
Why Choose Metal Roofing?
When installed with decking, underlayment and insulation, metal roofing isn’t any louder than traditional shingle roofing. Compared to shingle roofing, metal roofing offers superior longevity, durability and sustainability. Metal roofing offers a lifespan of 50 years or longer. It can also stand up to harsh weather conditions such as high winds and heavy snow loads. Metal panels are made from 25%-35% recycled materials and are virtually 100% recyclable at the end of their life.
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.
How Can Ice Dams Be Prevented?
To prevent ice dams, follow these four steps:
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.
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.
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.
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.
Additional considerations for working with metal panels in winter.
In part one of our series on metal roofing and snow, we covered five of the most important elements to consider when preparing structures for winter weather. In this post, we’ll review four more ways to prevent unexpected, costly damage of metal panels in winter.
Consider roof material and surface color
Metal roofs absorb heat quickly and radiate it effectively. Darker panel colors can enhance this solar absorption effect, which can save you money year-round. But because UV light can pass through 3-5 inches of snow, when combined with heat loss through the roof, it becomes more difficult for snow to stay solid. To minimize the chance of ice damming, you should ensure your roof system is properly sealed and insulated. If not, ice damming may occur and the melting and re-freezing of snow throughout the day can result in icy layers that promote snow sliding—no matter the roof material or color.
Review weathertightness factors
For low-sloped roofs (less than 3:12), it is especially important for panel seams to be watertight to prevent water (melted snow) from leaking into the structure. This can be problematic when snow gathers and stays on a roof. Architects, designers and specifiers, therefore, should consider using panels that have passed the ASTM 2140 water head test or FM 4471 Appendix G water test. Water-resistant underlayment should also be considered for all roof slopes.
A close-up of this dormer roof illustrates how the impact of sliding ice and snow can damage panel seams.
Consider your roof layout
Design elements like valleys and slope changes cause snow to collect and increases your snow load. Also, when dormers extend from a large roof area and one area is significantly bigger than the other, the structure is susceptible to experiencing unbalanced sliding snow. This imbalance can actually tear open standing seams and displace panels. Also consider that drifting snow may accumulate behind HVAC units, at perimeter walls, and behind solar and photovoltaic (PV) panels.
Ensure Proper Roof Maintenance
One of the best ways to prevent snow and ice issues is to regularly inspect and maintain your roof. In addition to cleaning and inspecting your roof for possible issues, properly removing standing snow and preventing ice dams is a vital part of avoiding damage to your metal panels in winter. This often requires that you get into your attic to inspect for air leaks—the leading cause of ice dams. Read more about how to properly maintain and remove snow from your roof in this blog post.
If an issue is discovered, consult your roofing material manufacturer for recommendations as well as advice on warranty claims. Additionally, you can reach out to a trusted roofing professional in your area. These professionals can thoroughly inspect your roof system to help you determine ways to rectify any potential issues. You’ll want to do this before damage and/or injury occurs and before you pay for sub-par or ineffective repairs.
If you missed part one of this series, click here for our top five considerations. These include managing snow load and sliding snow, preventing ice dams, using retention systems and more! For more information on how metal panels fare in winter weather conditions and for advice on how to winter-proof your roof, reach out to an ABC representative today.
What to consider when designing and building in snow-prone areas.
While properly-designed metal roofs historically perform well in winter, heavy snowfall can be detrimental to buildings of all kinds. Those who live and work in and around them are also at risk when snow and ice cause dangerous situations. Even though winter doesn’t formally begin until late December, colder weather is upon us. And while you might not be expecting snow or ice yet, keep these roofing and snow tips in mind when designing, constructing and maintaining structures in areas where there’s a chance for snow and/or ice over the course of the year.
Considerations for Snow-Bearing Roofs:
Anticipate Snow Load
Snow accumulates on every roof type, and as this happens, it increases the amount of weight your structure is bearing. This increased weight (snow load) can pose several threats to the structure and those in and around it. For example, when the weight of snow or ponded water from melted snow exceeds the structure’s limits, the roof or even the entire structure can collapse. Be sure you’re aware of the weight your structure can bear and remove snow to keep it within its limits. Consult the International Building Code (IBC) as well as state and local codes for guidance based on your location.
Prevent Ice Dams
Most ice dams are the result of air barrier flaws in buildings. If warm indoor air escapes through the roof floor, it warms the roof sheathing and melts the underside of the layer of snow on top. This water then moves down the slope of the roof toward the eaves, where it freezes into ice. As this process continues, the ice gets thicker and thicker, resulting in ice dams. The presence of these dams allow water to back up and form a reservoir that can cause major damage.
To prevent ice dams, you should:
Seal all air leaks at the attic floor
Ensure proper insulation
Provide adequate attic ventilation
Another tip is to use a peel and stick membrane on the roof deck extending from the eave to about 3’ up-slope from the exterior wall. For more specific details on the ice dam prevention tips above, read our recent blog post.
Prevent Sliding Snow
Gravity can cause accumulated snow to slide down the roof’s slope (shedding), potentially injuring people and damaging property below. Despite this, snow shedding must occur to keep the snow load from accumulating beyond the buildings structural limits. Balancing snow load and shedding is important and requires that you consider geographical and building material and roof design factors.
Ice and snow sliding down the main roof has damaged the roof panels and the valley trim on this connector roof.
Roof slopes of 45 degrees (12:12) or more, can accelerate sliding snow with sometimes immense and dangerous consequences. For example, if snow accumulates and then falls onto an exterior gas line, pipes could rupture. From there, the smallest of ignition sources could set the structure ablaze. In addition, the weight of sliding snow can propel any icicles formed on eaves can be propelled down by the force and weight of sliding snow onto people and property below.
On slopes less than 45 degrees (6:12 to 9:12), low amounts of friction (like on smooth roof surfaces) means it offers less resistance to sliding. Striations and embossing on roofing materials like metal panels add a small 3D profile and improve the resistance to sliding, especially when they run traverse to the slope.
This can get complicated, but in general, installing metal panels with snow retention devices on a steeply-sloped roof is recommended. This approach will naturally shed snow and ice, and protect your structure from excessive snow loads. If you have a low-sloped roof, be sure it’s design supports snow as shedding won’t occur naturally. Including enough snow retention devices from ridge to eave is also imperative for this design.
Use Retention Systems
A variety of retention options, such as snow fences, bars or guards, are designed to make snow and ice melt completely or fall from roofs in small amounts. This helps reduce risks associated with sudden rooftop avalanches while maintaining the clean lines of the roof. It is important that snow retention systems are carefully engineered and properly installed. Models like S-5!’s snow-retention device design resource allow you to input your roof dimensions and expected snow load to adequately engineer snow fence assemblies.
Protect Roof Attachments
This pipe penetration is protected from sliding ice and snow by a small section of S-5! ColorGuard to the panel seams immediately up-slope from the pipe.
The weight of sliding snow can be powerful enough to take off attachments like exhaust vents. To combat this, reduce the shear load by installing rigid vent pipes securely and as high up on the roof slope as possible. If this is not possible, protect the pipes with a snow retention system.
While metal roofing responds well to harsh winter weather, it is imperative to take the time to keep snow, ice and moisture from causing issues. No matter the roofing design or material used, keeping people and property safe from overhead dangers should be a priority when designing, installing and maintain your structure.
In part two of this roofing and snow series, we’ll review additional considerations. It contains tips on roof layout, color, weathertightness and maintenance, which also play important roles in winter weather protection.
For more information on roofing and snow like how metal panels fare in winter weather conditions and for advice on how to winter-proof your roof, reach out to an ABC representative today.
Login
