Single Ply Roofing
Due to the ease of installation and relatively inexpensive material costs, single ply roof systems have become the industry leader over the past 15 years.
TPO (Thermoplastic Olefin) has exploded in the roofing industry in the past 10 years. Heat welded seams and 10’x100’ rolls make TPO the leader of single ply systems. It can be fully adhered or mechanically attached. Typically, TPO is light in color and reflective of ultra violet rays. In most circumstances TPO can provide the owner with a 20 year manufacturer’s warranty.
EPDM (Ethylene Propylene Diene Terpolymer) is normally black in color (but available in white) and was the primary single ply membrane along with PVC until the emergence of TPO. It also comes in 10’x100’ rolls. The seams are adhered using double-sided tape as opposed to being heat welded. EPDM can be mechanically attached or fully adhered as well.
PVC (Polyvinyl Chloride) has been a successful roofing system in existence for over 50 years in the United States. Its durability and chemical resistance make it a favorite for restaurants and large manufacturing plants. Similar to TPO, PVC has heat welded seams and can be mechanically attached or fully adhered. Unfortunately, the cost to manufacture PVC has risen dramatically in recent years making it less attractive for owners looking for a single ply roof system.
Liquid-applied systems are relatively new to the commercial market. They are seamless and fully reinforced and are ideal when the use of roofing sheets are difficult. Most manufacturers now require liquid-applied flashing on various details for their modified bitumen warrantied systems. Liquid-applied systems are much more expensive than the other flat roof types and are considered the Rolls Royce of the industry.
IRMA (Inverted Roof Membrane Assembly) roof systems are the most common type of flat roof system used on modern high-rises today. They consist of a waterproofing membrane (single ply, liquid-applied, modified bitumen or built-up) directly adhered to a concrete deck, a drainage mat layer and insulation resistant to atmospheric degradation. The assembly is held down with a form of ballast, such as gravel, wooden decking or paving stones (most common). An expected 40 year life cycle is its greatest benefit.
Green roofs are a type of IRMA system with multiple choices of landscaping as its finished surface. Green roofs are becoming more popular in urban areas where flat roof tops can be converted into pleasant green spaces for residents who may not have access to parks nearby.