Built-up roofing (BUR) is a top choice for any flat or low-slope roof, most notably in climates similar to that of North Las Vegas. The system is composed of layers upon layers of bitumen and reinforcing fabrics; these layers alone give it the appearance of a roof with "depth." Yet when you touch it, it's actually quite smooth. In our monsoon season (infrequent though it is), BUR keeps the water out. In our UV-exposed, high-heat summer days, it keeps the inside cool (in part because the insulation above the BUR is working, too)—and that was a concern when they were choosing the materials to build this particular stage of the complex. One of the most popular built-up roofing systems is tar and gravel. "Surfacing" (as it is called) with gravel is a no-brainer for a building in a desert, which "surfaced" on June 1, 2011.
Another common type of flat roofing is the modified bitumen system. An evolution of traditional tar and gravel systems, modified bitumen uses modern materials, such as polymers, to increase flexibility and durability. On the one hand, polymer-based systems are incredibly versatile—they can be installed using three completely different methods: (1) cold adhesives, (2) hot adhesives, or (3) self-adhering sheets. On the other hand, they're also incredibly resilient in extreme temperatures. In fact, systems here in North Las Vegas likely experience some of the most extreme temperature swings (up to 120°F in the summer and down to 20°F in the winter) that those systems will ever see. Another benefit of this system is its reflective surface option, which is supposed to help reduce cooling costs by minimizing heat absorption.
For those who want a roof that incorporates the latest developments in building technology, a single-ply membrane might be the answer. You see, this is a roof system that consists of just one layer, rather than the multiple layers that you typically get with a built-up system. Single-ply membranes come with their own set of advantages, too. First off, they're lighter. Even if you were to use the heaviest single-ply membrane, it would still weigh less than if you used a "traditional" built-up system. The second advantage is that they are fewer seams. The seams that you find in the single-ply system are compiled to one area of the roof, thus providing less of a chance for "leakage" than if the seams were to be dispersed around the surface of the structure.
