How to Address Design Considerations When Working with Metal Roofing

As a fast-growing segment of the roofing industry, many architects are turning to metal roofing to create energy-efficient, attractive roofs suitable for commercial and residential properties. The days of simplistic, unattractive metal roofs are long gone. However, design considerations still need to be incorporated to ensure the ideal aesthetic is achieved. From valleys to skylight installation, solutions exist to minimize any risks of less-than-desirable finished features.

What to Know About Standing Seam Metal Roof Design

When designing a standing seam metal roof, there are certain design elements that must be considered to deliver optimum performance of the roofing system.

• Dead valleys or any areas of the roof where water can't drain away freely
• Complex design areas, especially at intersecting planes
• Significant valleys and curbs
• Internal gutter designs

Each of these areas can be challenging for metal roof installations and when not properly addressed leads to roof leaks and in extreme cases total failure of the roofing system.

What Solutions Exist to Minimize Risk?

As an architect, it's critical to consider complicated roof design early in the design process to minimize the risk of failure and maximize opportunities for success.

For architects who want to improve the overall durability of these areas, more extensive fasteners may seem like the solution. However, that is not necessarily correct.

Dead Valleys

A dead valley is a low point in a roofing system that allows the accumulation of water leading to potential leaks, water damage, and other problems if not properly addressed. During the design of the roofing system, dead valleys should be avoided if at all possible. When they cannot be avoided, extreme care must be taken during the specification and installation of a 0.080 welded aluminum or 18 gauge welded stainless diverter.

Intersecting Planes

An intersecting roof plane refers to the area where two or more roof surfaces meet. While a fairly common condition on more complicated roof planes, it’s important to address the area during the design phase to ensure proper drainage and with proper trim detailing and care during installation.

Roof Curbs:

Roof curbs support and accommodate various types of rooftop equipment. When properly designed and installed, they support the weight of the equipment, elevate it off the roof plane, and represent a critical element in the weather integrity of the entire roofing system.

While roof curbs can be made from various materials, to ensure the roofing curb matches the decades-long performance of metal roofing, we routinely recommend they be made from 18 ga. Stainless or 0.080 welded aluminum.

Large Valleys:

Most roof plans include at least one, if not multiple, valley conditions. When properly designed and installed, valley conditions work well with metal roofing. However, large valleys require special consideration due to the volume of water and snow that may accumulate.

When working with valley conditions over 20” wide, it’s important to specify wider valley pans and taller diverters than normal.

Internal Gutters:

An internal gutter is integrated inside the structure of the building as opposed to being attached to the exterior.

While internal gutters are fairly common in flat and low-sloped roofing systems, they are not recommended for metal roof installations. Consequently, it’s best to remove them from the project design. When removal isn’t feasible, we recommend the gutter be made from welded aluminum and then lined with either EPDM or Single-Ply roofing material to facilitate proper maintenance, repair, and replacement to match the decade’s long life expectancy of metal roofing.

The Importance of Incorporating a Solution to High-Risk Areas

To deliver optimal performance, it’s critically important to devote time and attention to challenging areas during the design phase. And that certainly holds true for standing seam metal roofing projects for several core reasons.

Standing seam roof durability is dependent on it

If there is any application of interior materials or improper installation outside of the manufacturer's recommendations, these areas are most likely to fail. This includes skylights, valleys, curbs, and parapet walls. As an architect, it's obvious to you what these areas do to the strength and durability of the metal roof. They create weak areas that must be addressed.

Durability is at risk without a specifically selected solution designed to provide extra protection in those areas. Over time, this can lead to the entire metal roof system failing.

Weathertightness is a concern

Weather tightness is one of the biggest risks to metal roof success, including standing seam roofs.

When standing water is present for any length of time, it can degrade the metal and ultimately lead to a failure of the metal and the substrate under the metal which can ultimately result in water penetration into the building envelope.

Warranty concerns may also be a factor

While not common in residential applications, many commercial standing seam roofing projects include a weathertightness warranty.

Many manufacturers exclude complex areas like dead valleys, intersecting planes, internal gutters and extensive curbs. Consequently, it’s always best to visit with your chosen manufacturers early in the project planning to discuss and address any warranty concerns.

Finding the Right Solution for Your Project

Metal roofs are fantastic options for today's more challenging architectural designs, whether for a home or a commercial structure. However, architects and builders need plans to ensure durability and weathertightness when implementing solutions designed specifically for standing seam roofs.

Contact us to discuss your building specifics so we can help you experience the best possible results.