Upgrading Your Roof with Metal Panels

In a recent blog post, we reviewed key considerations to help a building owner decide whether to repair or replace a damaged roof. In this post, we’ll address some ways metal roofing systems are an advantage when upgrading your roof and restoring your building to “like-new”, weathertight condition.

MBCI Blog: Upgrading Your Roof with Metal Panels

Installing Metal Panels Over Existing Roofing

Some owners are concerned about replacing a roof because they dread the cost of removing the existing roof. This concern is valid in many low-slope roofing situations because the new roofing membrane might not be compatible with the existing one, and could cause premature deterioration. There are, however, metal panels specifically designed to be installed directly over existing roofing. And, many of these retrofit systems can be installed over existing roofs made of metal or other materials. Avoiding removal of the old roof obviously saves on cost. However, it also saves considerable time when installing the new roof. As an exposed-fastener metal roofing system, this retrofit application also requires fewer construction components, further streamlining the installation process.

Retrofit metal panels typically feature a membrane treatment that prevents rust or contaminants from the old building materials from transferring to the new panels. This is a versatile solution for both low- and steep-slope roofs (minimum slope: ½:12). It is also very durable and can feature approvals for use in extreme weather locations, including Florida. Metal panels are available in a variety of colors that enhance the overall design of a building. Often, this “replacement metal over existing roofing” approach is the most cost-effective, even compared to some repairs. Additionally, new roofing is more likely be eligible for a warranty, while repairs rarely, if ever, are.

Upgrading Your Roof with Insulated Metal Panels

Energy conservation is on the mind of many building owners and building code enforcement officals. Therefore, adding insulation when upgrading your roof is often required to adhere to building codes. In this case, applying zee-shaped sub-purlins over the existing roof system helps support a new layer of metal roofing. In between the sub-purlins, insulation can be added to meet or exceed current energy code requirements. This system also eliminates the need to remove the existing roofing while providing an added layer (or more) of insulation to improve the overall energy performance of the building. Insulated metal panels (IMPs) like MBCI’s can help keep buildings cooler in summer and warmer in winter—conserving energy year-round.

Sub-purlin systems can fit any existing metal panel, support new panels, and be made to accommodate many types of insulation between the old and new roofs. They can also  support or incorporate a variety of solar energy systems where desired. Roof panel options include variety of profile shapes, textures and colors to suit aesthetic preferences.

Altering the Roof Slope

In some cases, upgrading your roof means changing the roof slope (i.e., turning a low-slope roof into a steeper-sloped roof). In these cases, metal roofing systems can be the most economical choice. Steel framing (16-ga. to 12-ga.) installed over the existing roof frame creates a sloped plane that can support new metal roofing panels. Note that the existing physical shape of the roof, the existing structural system and other rooftop conditions are usually the biggest factors in the geometry and shape of the new roof. Nonetheless, the beauty of the system is that it can dramatically improve the appearance and drainage of a building’s roof, regardless of whether the substrate is steel, wood or concrete.

Lower-slope applications (1/2: to 2:12) are typically driven by economy and designed to efficiently discharge rainwater from the roof. Higher-slope applications (greater than 2:12) often serve to improve and update the look of an existing building. They achieve this by showcasing the metal roof while also improving its drainage and durability. Once the framing is installed, standing-seam metal panels can be installed over the top, creating a ventilated attic space. This allows space for additional insulation , thus improving the energy performance of the building.

Working with Building Professionals

Any of these options are applicable over an existing metal roofing system. They cab also convert other types of roofing systems to longer-lasting metal roofing, or replace an existing roofing system altogether. Of course, engaging the services of a design professional (architect, engineer, etc.) is always appropriate when considering your options. They can help properly assess existing building conditions and recommend the best overall metal roofing solution from metal panel manufacturers.

To learn more about upgrading your roof system with more durable, longer-lasting, better-draining and easier-to-maintain metal roofing systems, contact your local MBCI representative.

Are Metal Panels An Ideal Low-Slope Roofing Material?

Many large, commercial, low-rise buildings often don’t benefit from steeply-sloped roofs the way residences and small commercial buildings might. This is because a steep roof slope would add unwanted height and unnecessary construction cost. Buildings like warehouses, retail stores, etc. are more appropriately built with low-slope roofing, commonly known as “flat roofs”. The National Roofing Contractors Association (NRCA) defines low-slope roofs as those with “a slope at or less than 3:12″. Anything steeper qualifies as a “high-slope roof”. With this in mind, let’s look at some key points to consider when designing and constructing a low-slope roof.

MBCI Low-Slope Roofing

 Low-Slope Roofing Materials

When it comes to selecting low-slope roofing products, there are generally three fundamental choices:

  • Asphalt/ Bituminuous Products: The traditional commercial roofing norm for many years, the use of asphalt/bituminous products has dwindled as newer, more appealing options have emerged.
  • Flexible Membrane Roofing: This roofing material can be made from a variety of types of plastic/polymer-based materials (commonly known as EPDM, TPO, PVC, etc.). Rolls of the chosen membrane are laid out on the roof structure and secured in place either with mechanical fasteners (screws with large washers) or with a continuous layer of adhesive.
  • Metal Roofing: Sometimes overlooked, metal roofing is suitable for different roof slopes. Many metal roofs that use standing-seam systems are rated for use with a pitch as low as ½:12.

When considering which type of roofing material to use for a building project, there are a number of significant differences that illustrate why metal roofing is often the ideal choice.

Engineered For Superior Performance

Standing-seam metal roofing is made specifically for use on low-slope roofs as it meets a number of performance requirements:

  • Water resistance: Precipitation doesn’t penetrate through metal or through the standing seams where the metal panels join together. This is why they can tolerate such low slopes, allowing the water to drain away slowly and predictably without leakage.
  • Rigidity: The rigid nature of metal means that there is less opportunity for ponding (standing water). This is not always the case with asphalt/bituminous or membrane roofing systems.
  • Drainage: Metal roofs carry water to the building’s edge toward gutters and downspouts that carry it away from the building. Other roofing systems rely on drainage piped inside the building. This takes up space and has the potential to leak water inside the building and cause damage.
  • Wind Resistance: Standardized uplift testing shows that metal roofing performs as well or better in extreme weather than mechanically-fastened or fully-adhered membrane systems.
  • Durability: The most cited advantage of metal roofing is its long-term strength and durability. Engineered design and use of high-quality coatings ensures a longer lifespan—50 years or more. In contrast, other roofing types typically feature lifespan ratings of 20 or 30 years.
  • Puncture Resistance: Low-slope metal roofing is more puncture-resistant than asphalt/bituminous or membrane roofing. This makes it better able to tolerate foot traffic, hail and other puncture-inducing hazards.
  • Construction/ Installation Ease: Metal roofing panels are custom-made to suit specific building sizes and end uses. This customization typically means it takes less time to place and install metal roofing in the field. Further, metal panels can tolerate a wide range of temperatures and weather conditions and still install and perform as intended. Low-slope roofs are also safer to walk on with less risk of slips, falls and other hazards.

Cost-Effectiveness

Using metal roofing on low-slope roofing systems can be cost effective in a number of ways:

  • Fewer labor hours as a result of the ease of installation saves money during construction.
  • Competitive material costs, particularly if the metal roofing is part of a total metal building package from a single manufacturer.
  • Minimal maintenance requirements and aversion to rusting, mold growth and decay that save the building owner money over time.

This all adds up to a very favorable life-cycle cost.

The performance, cost-effectiveness and life-cycle benefits of metal roofing panels make them a viable option for low-slope roofing systems. Manufacturers like MBCI can help you select the right metal roofing products and provide information and resources to help ensure proper installation.

View examples of low-slope metal roofing projects and contact your local MBCI representative to start your project today.

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