Roofing SystemsEPDM – Ethylene Propylene Diene Monomer
EPDM has been traditionally referred to as a black rubber roof membrane which is seamed together with a double-sided tape. There are three primary roof systems (EPDM) applications: Ballasted, Fully Adhered and Mechanically attached.
Ballasted rubber roof systems utilize large rolls of EPDM, which are held in place with a ¾” – 1 ½” Round - Washed stone ballast. Fully Adhered rubber roof systems utilize an attachment system in which the roof insulation is mechanically anchored to the roof deck, and the rubber membrane (EPDM) is then adhered to the roof insulation with an adhesive. Mechanically attached roof systems (EPDM) utilize a system in which both the roof insulation and the rubber membrane are mechanically fastened into the roof deck.
Rubber roof systems (EPDM) have been used in cold weather states more than any other roof system over the past 15-20 years. They have a solid track-record, and they have been improved upon greatly since their original inception. Since the EPDM material is essentially comprised of rubber, the material has strong elastic capabilities to withstand building movement and contraction. EPDM roof systems also represent a labor savings compared to the more traditional roof applications. As with all single-ply membranes, the biggest weakness to an EPDM roof system is that it can be prone to membrane punctures from third parties or blowing objects. It should be said however, that these types of occurrences are fairly rare.
The growth of EPDM roofing has stabilized due to the popularity of white roof systems, particularly in the southern states. Since the color black retains heat, there is a strong argument that EPDM has more energy-saving capabilities than white systems in states in which there are more cool days than warm days. In response to the market trending to white membranes however, white-colored EPDM has been recently introduced into the marketplace.
TPO/PVC - Thermoplastic Olefin & Polyvinyl Chloride
TPO and PVC are white-colored single-ply roof systems which are growing in popularity due to the belief that a reflective white roof substrate is beneficial to the environment. TPO and PVC are different in molecular formulations, but the installation procedures are similar. These roof systems utilize a seaming system in which the membrane laps are heat-welded using a sophisticated heat gun apparatus. The TPO variation is a newer product which was introduced to the market within the last decade.
PVC roof systems have had a spotty history in the northern climates, and they are losing market share to TPO roof systems. Earlier PVC systems, particularly those which did not utilize a membrane reinforcement scrim, were prone to cracking or shattering of the membrane. The new PVC systems utilize a reinforced membrane and they have alleviated many of the concerns from the 1980s – ‘90s. The main cause for their declining market share is based on the belief that TPO membrane is more environmentally friendly than PVC membrane.
The TPO roof system is the fastest growing roof system in the country. TPO is preferred over PVC by many roof specialist, not only because of the environmental aspect, but also because TPO generally costs less than PVC. TPO roof systems generally require less labor than adhered EPDM roof systems and their growth is being fueled from their popularity on new construction projects.
There is hesitancy from many roofing contractors and roof consultants in the Mid-west to jump on the TPO bandwagon. Since the system is relatively new, there are some fears that the roof system could run into unexpected performance problems. Also, there is no evidence to suggest that the white membrane is environmentally beneficial in cold-weather states. Most roofing experts agree that white membranes do not hold their reflectivity beyond the first several years of the original installation, and that increasing insulation R-Value beneath the roof system, is the best way to obtain long term energy savings. It should be noted however, that mandating white roof systems in densely populated urban areas, may reduce the heat island affect in major cities.
White TPO roof systems may have a prominent future in the roofing industry, especially in the southern states. While we continue to install a great deal of TPO roofing due to the market-driven desire to have a white-colored roof, we are still waiting to analyze the full track record of this relatively new system.
Built up Modified Roof Systems
A modified roof is a roof system which utilizes the asphaltic products associated with a built-up roof, and the installation techniques associated with many single-ply systems. The theory is that the final system will have the durability of a built-up roof, however, with less labor cost(s).
There are two basic types of modified installations: the APP and the SBS. The APP system is often referred to as a, “torch down roof.” The SBS system is a 36” granulated roll of roofing which on the surface, resembles a shingle-like material. APP roofs are generally melted down with a torch, while SBS roof systems can be torched or mopped down with hot or cold asphalt.
Torch down roofs do not have a good reputation in many regions. Many reputable roofing contractors are reluctant to carry the insurance requirements associated with a roof system which has a high risk of starting a building fire. Torch down roofs also do not perform well when a roof substrate does not have positive drainage. We only recommend torch down roof assemblies over smooth-surfaced roofs which have above-average drainage.
SBS roof systems which are installed with asphalt can be reliable roof systems when installed well. This type of system, particularly with a white granulated surface, is very popular in the southern states. In northern states however, SBS systems represent a small segment of the roofing market. SBS systems require a warm outside temperature during the installation process. This installation requirement can be problematic in cold-weathered states.
Coated Roofing Systems / Cool Roofs
Coating applications are becoming hotter topics in the commercial roofing industry. With these types of roofing applications, coating is typically applied over an existing roof system. These roof systems are marketed on the concept(s) of lower disposal costs, higher insulation values and long-term roofing warranties for less cost. It should be noted that there are myriad roof coating applications and that there are coating systems which do not utilize spray foam insulations.
There is no question that the concept of coating over an existing commercial roof for lower cost and less landfill space has appeal in the present market place.
Applying a liquid-spray coating over an existing flat roof is relatively new development in the commercial roofing industry. These systems generally utilize a preparation process and then a two-part coating.
A green roof - sometimes also called a cool roof - is considered environmentally superior because it saves energy. Usually white in color, these roofs reflect the heat of the sun off of the surface of the roof. It means that heat is not passed through to the interior of your building below. The government ENERGY STAR ® program estimates that you could see air conditioning energy use drop an average of 25% and as high as 50%!
A white or light colored roof gives your building a high-quality appearance. It looks clean, modern and seamless. The roof lasts longer because UV deterioration is minimal. Ultra violet rays are the enemy of most roofing materials. It makes sense that if a green roof reflects away solar rays, the damage from sun exposure is greatly reduced. You can have us measure and install a cool roofing material on a flat roof, or one with a low slope.
Metal roofs come in several major types: concealed fastener systems¹ include mechanical lock and snap-lock assembly systems: double-lock, batten seam, and t-panel are among the most common concealed fastener panels. Snap together systems such as batten seam and t-panel are often used in instances where a locked assembly system won’t work—such as curved roof surfaces.
Can I walk on a metal roof?
Yes you can; however, like walking on any roof, you should be careful.
Is a metal roof noisy when it rains?
No, metal roofs are not noisy when it rains. According to one study, the noise levels of a metal roof are about the same as other roofing products such as asphalt or wood shingles or clay tiles.
Is a metal roof damaged by hail?
Metal roofs are very tough and highly resistant to hail damage…much more so than asphalt/fiberglass shingles. In fact, many metal roofing products have the highest impact resistance and hail rating granted by the insurance commissions in the hail belt regions of the U.S. Some insurance companies even provide a reduced rate for metal roofs.
How about resistance to wind damage?
All metal roofing products are very wind resistant. Many styles have been tested to withstand hurricane force winds; and winds warranties can be as high as 120mph.
Is a metal roof fire safe?
A steel roof is the most fire safe roof. It is classified as a noncombustible roofing material with a Class “A” rating – the highest rating given.
How much does the weight of a metal roof compare to other types of roofing?
Much to many peoples surprise, metal roofs are significantly lighter than other types of roofs. Typically they weigh less than one-third the weight of asphalt/fiberglass shingles; and are as much as 75% lighter than clay, concrete or slate.
Will a metal roof rust?
Galvalume coated steel roofing panels are protected by layers of metallic and polymer coatings. Industry studies have repeatedly shown them to outperform the corrosion resistance of other coated metals. They are available with warranty’s as long as 50 years.
Does the color fade?
Metal roofs are painted with high-performance polymers that have exceptional weathering properties. Over time you might notice a slight change in color due to the settling of airborne contamination, but occasional rain or washing the roof with a garden hose (from the ground) will keep the roof looking like new.
What about lightning?
Steel roofing is no more susceptible to lightning than any other roofing material. Lightning most frequently strikes the highest point in any terrain; and if your roof is at the highest point of the surrounding terrain, you can install lightning rods.
If I’m re-roofing, do I have to remove the old roof before installing the metal roof?
Usually not if you’re installing the metal roof over existing asphalt, fiberglass or composition shingles (maximum of two layers thick). In most situations, the metal roof can be installed directly over the old roof.
Will a metal roof make my house hot?
Actually, a metal roof can save you money on you’re HVAC costs because it has a higher heat reflectivity than other roofing products like asphalt/fiberglass shingles, wood, tile, etc. During the summer it makes buildings cooler by efficiently reflecting away sunlight and reducing the amount of heat transmitted into the building. Likewise, it makes buildings warmer in the winter by reflecting inside heat from the underside of the roof back into the building. This good thermal reflectivity translates into energy savings by reducing cooling costs in the summer and heating costs in the winter.