Commercial Roofing System Pros and Cons for your Building, Business and Budget

Advances in commercial re-roofing systems give building owners and facility managers many viable options. They also now have access to a lot more data to make smart, calculated decisions.

Choosing the right roof system means it’s the best fit not only for your budget, but for your building and everything housed within it as well. Effectively sort through the pros and cons of each major type of roof system, including:

  • Pitch
  • Penetrations
  • Climate
  • Foot traffic
  • Drainage
  • Aesthetics
  • Brand
  • Projected length of ownership
  • Sustainability
  • Installation costs
  • Upkeep and ease of maintenance
  • Warranty

Priorities will dictate which of these factors should be weighed more heavily than others. Here is an objective look at the advantages and disadvantages of built-up, metal and single-ply systems weighed against these factors.

BUILT-UP ROOFS

Built-up roofing (BUR) is a tried-and-true roof system that has been a popular option for more than 100 years. It generally consists of layers of tar, asphalt and other support materials as the base, and then a top layer of gravel or stone.

PRIMARY ADVANTAGES:
  • Installation cost. They are relatively easy to install and materials used are modestly priced when compared to other types of roof systems.
  • Ease of maintenance. They require minimal attention and service once installed other than routine maintenance and inspections. Repairs to the top layer are relatively easy to do, but finding leaks below the top layer can prove to be difficult.
  • They have multiple layers, including a top layer with no joints or seams, which strengthens their waterproofing properties. The multiple layers also make it more conducive to foot traffic when compared to some other roof systems. They also provide excellent UV protection that helps extend the useful life of the membrane, reduce roof temperature and prevent extreme fluctuations in temperatures inside the building.
  • Useful life. They can last more than 30 years when properly installed and maintained.
PRIMARY DISADVANTAGES:
  • Cold weather performance. BUR systems are rather inflexible. They typically perform better in mild or warm climates than in extreme cold ones.
  • During installation, toxic odors can be released from the heated tar and asphalt.
  • The multiple layers of tar, asphalt and stone/gravel add significant weight to the building’s structure, sometimes requiring reinforced roof joists.
  • These roofs are built for functionality; not for looks. BUR systems are not the best choice on visible roofs for those businesses with specified aesthetics.

METAL ROOFS

Metal roofs are generally considered to be the longest-lasting roofing system of the three primary types. Some may have the ability to last 50-plus years when installed and maintained correctly. Not all metal roofs are the same, though. There are different lengths, shapes and material types of panels, different gauges of panels, and different types of fastening systems that adhere them to the building. All of these factors can have an effect on how the roof performs.

PRIMARY ADVANTAGES:
  • No disputing this metal roof advantage, however they’re far from “set it and forget it.” Metal roofs still need proper care and maintenance to get the expected length of wear time out of them.
  • Ease of maintenance. Standing seam metal roofs, which are a little more expensive than the alternative exposed fastener system, can be easier to maintain. Exposed fasteners tend to degrade or come loose through building expansion and contraction. This can easily lead to leaks if not regularly watched for and dealt with.
  • Metal roofs have a sleek, high-end look and can be custom colored with coatings and paint offerings to match a company’s brand guidelines.
  • Weather resistant. Metal roofs can be highly resistant to UV, rain, snow, mold and mildew. Metal is also noncombustible and resistant to fire.
PRIMARY DISADVANTAGES:
  • Installation cost. Higher-end metal roofing systems can require a larger investment at the time of installation. This is due to both the cost of materials as well as the labor-intensive process it requires to do the job right. Over time, however, the return on investment can pay off if well-maintained.
  • For buildings with a lot of penetrations metal roofs can pose a problem. The more holes needed to punch into a metal roof (pipes, vents, skylights, etc.), the more opportunities there are for water to get in.
  • Foot traffic – Metal roofs are prone to denting with foot traffic from technicians accessing the roof to service HVAC units, etc. Hail can also dent a metal roof.
  • Noise – Rain and hail can create excessive noise on metal roofs when not sufficiently insulated.

SINGLE-PLY ROOFS

Single-ply roofs are by far the most common roofing systems today. They also have the broadest array of options, thicknesses and price points. The best-known single-ply roofs are made from rubber (EPDM) or plastic (TPO, PVC) compounds.

PRIMARY ADVANTAGES:
  • Installation cost. Many facility managers are attracted to the relatively low installation cost but ignore the common longer-term ramifications.
  • Lightweight and flexible. Single-ply roofs put less stress on a building’s structure than other roof systems. Their flexibility helps them stretch and adapt to a building’s natural movement.
  • Utilities costs. Single-ply systems can be white, gray or black depending on the climate. This can help to maximize reflective or heat-retaining qualities and minimize utility costs inside the building.
PRIMARY DISADVANTAGES:
  • One of the trade-offs of the lower initial cost of single-ply systems is their expected useful life. Their seams are prone to leaks, so many of them start showing noticeable wear within 5-7 years.
  • Foot traffic and debris can easily damage, if not puncture, a single-ply roof.
  • Buildings with a lot of penetrations can see higher installation costs and be prone to more leaks in and around those areas.

A newer type of single-ply alternative using cross-linked polymers addresses many of the common disadvantages of single-ply roofs. They are typically reinforced to be stronger, thicker, more puncture-resistant and longer-lasting than standard single-ply roofs.

When building owners and facility managers think beyond the invoice of the job itself, they are empowered with a broader, longer-term view. These kinds of decisions  will be most advantageous to them in terms of building, business and budget.

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