Roofing Concepts Unlimited Blog

Commercial Roofing Replacement Products

When deciding what product to choose when **commercial roofing replacement **is necessary, there are several factors that need to be considered, keeping in mind that certain products may be best suited for certain applications and that not all products can be considered equal.

Let us discuss some of the factors that should be considered, assuming we are talking about a flat roof area:

1. Budget: All commercial/condominium roof products are relatively expensive; some substantially more than others depending upon the composition of the roof assembly i.e.: insulation type and thickness (if required) deck type, number of piles and complexity of detail work. A professional contractor will be able to help choose a roof product and corresponding assembly to meet the budget

2. Warranty Requirements: Most manufacturers now offer warranties ranging from 10 to 20 years. For a slight up charge, warranties can be issued in the form of a “No Dollar Limit” full replacement value warranty. What this means is that if the roof system were to fail prematurely because of poor workmanship or defective material, the manufacturer will repair or replace the roof to restore it to its watertight integrity. The “No dollar limit” means in basic terms, if your roof cost $75,000 to replace in 1999 and in the year 2009 would cost $175,000, your warranty would cover the current market value should the roof completely fail before the warranty expires. Of course there are terms and conditions to these warranties including the owners responsibility to implement pro-active maintenance. Your contractor should be able to supply sample copies of the proposed warranty so they can be thoroughly reviewed and understood.

  1. Design Criteria : This may be the most difficult area of consideration when choosing a roof product, especially for someone that is inexperienced in the do’s and don’ts of roofing. Areas of primary consideration are proper drainage- does the existing roof drain properly and adequately? Not only does South Florida building code require roofs to have a minimum of 1/8” per foot positive slope, most manufacturers will not warranty areas of roof subjected to ponding water. The industry and basic rule of thumb considers ponding water anything that remains beyond a 48 to 72 hour period under normal weather conditions. If your roof does not drain properly you must choose to install a “tapered insulation” system to create the required slope or choose a roof product that has no exclusions or limitations because of ponding water. We’ll discuss which do not in a moment.
    Other design criteria would be tied into the warranty requirement. Once the warranty requirement is determined, your contractor will then be able to design or recommend a system and related roof products that will qualify for the warranty. Depending upon the complexity of the project, you may wish to confer with an independent roofing consultant with assistance on design issues.

4. Occupant Sensitivity: Recently, it has become increasingly more of a problem, with people being very sensitive to what they breathe and smell. Most of us have seen, been around or experienced the unpleasant smells and odors that are associated with installing a new roof. This is most prevalent when installing a built up roof assembly with asphalt or coal tar pitch. Although this limited exposure poses no health risk, but merely an inconvenience, there are ways to minimize the odor including fume recovery systems. Ask your professional contractor for details on this topic.

There are several additional factors that may be considered when choosing a roof product, however the preceding are primary and should form a sound foundation for making a decision.

Let’s now briefly explore the different types of roof products:

For flat roofing, there are four (4) basic and most common categories: 1) Asphalt B.U.R.; 2) Coal tar pitch B.U.R.; 3) Modified Bitumen; 4) Single ply. If one were to look at a price spectrum, Asphalt B.U.R. could be the least expensive and Coal tar pitch could be the most expensive. Again design criteria would be a deciding factor.

Asphalt B.U.R. products offer warranties for up to twenty (20) years. They perform very well with proper maintenance. Asphalt B.U.R. requires positive drainage. Smooth, coated or gravel surfaces are optional. Asphalt B.U.R. products are the most conventional and time proven, next to Coal Tar Pitch.

Coal tar pitch products offer warranties for up to twenty (20) years. They perform very well and also require proper maintenance. Coal tar pitch has no exclusions or limitations for ponding water, so tapered insulation for positive slope would not be required. Historically, coal tar pitch roofs have lasted as long as fifty (50) years. Additionally, because of the extremely low melting characteristics of coal tar pitch, the products have been known to be self-sealing if minor damage occurs.

Modified bitumen roof systems offer warranties for up to twenty (20) years and are very popular in South Florida. Modified bitumen does have ponding water exclusions and positive drainage is recommended. Because of the material composition, more specifically the polyester reinforcement, these products are extremely flexible, puncture resistant and durable under foot traffic. This can be very important when air conditioners and other roof top equipment is present requiring continual repair and maintenance. Repairs, when necessary, are made easy and leak conditions are located easily. Modified bitumen roof products are high quality, mid-price range and increasingly popular. Proper maintenance is recommended and important to the long-term performance. Torch applied applications can eliminate odors associated with asphalt fumes.

Single ply roof products are varied. They are composed primarily of E.P.D.M. (rubber) P.V.C. and Hypalon. Most are bright white in color with the exception of Black Rubber. The white product can provide exceptional reflectivity from the hot Florida sun, which can reduce cooling costs for units directly below roof area. Warranties are also available for up to twenty (20) years but ten (10) years is the most popular. Most single ply products are reinforced with a polyester scrim for increased flexibility. Much consideration should be considered when choosing a single ply roof. Depending upon the application, they can be very costly. Single ply roof products are puncture resistant, but far from puncture proof. If a roof has a substantial amount of roof top equipment and air conditioners that would subject the roof to traffic by careless repair technicians, careful and selective consideration should be given. An unnoticed cut or slice in a mechanically fastened single ply roof product over a wood deck could spell disaster. Traffic pads could be incorporated with single ply roof products, but can do little if their presence is disregarded. Most have ponding water exclusions and also require maintenance to assure long term performance.

Choosing proper commercial roofing products can be a challenging task. With the proper research and question asking sessions with your contractor or consultant, a sound decision can be made and hopefully an education can be learned.