May 25, 2017
by Jason Allen
Many commercial buildings, and even some residential ones, have low slope or “flat” roofs that can be problematic to maintain. They typically rely on a membrane of some sort that in and of itself is waterproof, but every seam, penetration, flashing, and other detail is a potential leak if not installed and maintained properly. Further, the subsurface that the membrane sits on determines the actual slope to roof drains so if that is compromised, then standing water can sit on the roof and cause issues. Even the roof drains are a concern if they get clogged with debris or leaves and cause water to back up and stagnate on roofs.
Given the potential difficulties, and the frequency of replacement that is often needed for flat roofs (average of 20 years), it is no surprise that many facility managers or owners look to retrofit their buildings with sloped metal roofs wherever the size and geometry are conducive to it. In doing so they recognize the many benefits obtained which can include any or all of the following:
A complete metal roof system (e.g. metal framing, metal roofing, insulation, and ventilation) can be designed and installed to require minimal maintenance. That means not only fewer potential problems, but reduced operating costs over the course of many years.
Metal roofing is recognized by industry experts for having a very long lifespan even under challenging weather conditions. It is not uncommon for a metal roof system to last 60 or more years compared to a 20-year average for flat membrane roofs. If Galvalume® coated steel is used (i.e., zinc/aluminum coating licensed to roofing manufacturers), the roof lifespan can be expected to last the full service life of the building, according to studies done on standing seam roofs by the Zinc-Aluminum Coaters Association and the Metal Construction Association (MCA). Long-lasting roofing means there is only one installation to provide and pay for, not multiple ones over the life of the building.
Retrofitting with new insulated metal roofing systems is an excellent solution to high energy consumption and associated costs in a building. Retrofit systems can be designed to work over existing flat roofs or even over older sloped metal roofs to upgrade a building to meet or exceed current energy code requirements. Such systems add insulation between the old and new roof reducing heat gain in summer and heat loss in winter. The metal roofing can also be finished to reflect the heat of the sun away, achieving higher solar reflection index and reducing cooling costs.
In addition to energy efficiency, metal roofing systems can be made from recycled steel and then be re-used or recycled at the end of its service life. This capability helps reduce the amount of material headed to landfills and can contribute to points in the LEED green building rating system, among others.
Sloped metal roofs can be used as a significant design feature on many low rise and mid rise buildings. The range of colors and textures provides architects and other design professionals a full palette of options.
Curb appeal and long term performance are common contributers when a property is being assessed for value. A retrofit metal roofing system can certainly help in this regard.
Overall, there are many reasons for choosing a retrofit system for an existing building. Whether to replace a leaking roof, correct the current geometry, meet new regulation or code requirements, improve the aesthetics, or increase the energy efficiency of a building, all of the benefits above can be realized. To learn more about MBCI retrofit metal roofing systems and how they might work on a building you are involved in, visit www.mbci.com/products/retrofit-products.