Like residential roofing in Redmond, WA ,and the surrounding communities, commercial roofing systems require a great deal of attention, if not more, considering the level of investment involved not just in a roofing system but also the entire property it protects. If you’re serious about finding the best roofing option for your business, then you’re going to want to make sure that you have all your bases covered, starting with getting to know all the choices available to you.
1. Built-Up Roofing
Built-up roofing membranes (BUR) have been in use in the United States for over 100 years. They are referred to as “tar and gravel” roofs because they are composed of layers of bitumen (asphalt or coal tar) and reinforcing fabrics (sometimes called ply sheets or roofing felts and reinforced with either organic or fiberglass mats) topped with gravel as ballast or surfacing.
While traditional ballasted roofing is not adhered or anchored to decking material, BUR can sometimes have its base sheet, the bottom-most ply in a system, mechanically fastened. Also, the number of plies BURs have translated to the number of layers systems have. For example, four plies means a four-ply roofing membrane construction.
Given they have multiple layers, BURs are highly durable, able to withstand whatever Mother Nature throws at them. They also have excellent ultra-violet and waterproofing protection, as well as some fire resistance because of their surfacing layer.
This durability makes BUR easy to maintain, but the numerous layers can complicate the installation process. Once up, however, a BUR system can last an average of 15 to 30 years.
2. EPDM Single-Ply Membrane
There are two types of single-ply membranes, the first of which is thermoset membranes, such as ethylene propylene diene derpolymer (EPDM). Made of components derived from natural gas and oil, EPDM can be installed in several ways, including full adhesion, mechanical attachment (using batten bars) or ballasting, and, unlike BUR, is not installed with surfacings. To seal seams between sheets, specially formulated tape or liquid adhesives may be used.
While available to commercial properties for over 40 years now, EPDM only comes in black or white and two thicknesses (45 and 60 mils). It is sold in a wide range of widths, going anywhere from 7.5 to 50 feet, allowing for plenty of flexibility.
Thanks to its single-ply design, an EPDM flat roof in Seattle, WA, is easy to handle, simplifying the installation process, which can also help keep overall costs down. It is also tough and energy-efficient (when designed with cool roof coatings), making it ideal in a range of climates. In terms of lifespan, the commercial roofing option logs an average of 20 to 30 years.
Quick note: Consumers can often confuse EPDM for modified bitumen because roofing contractors colloquially refer to them as “rubber roofs.” In most instances, however, roofers are referring to EPDM when rubber roofing is involved.
3. PVC/TPO Single-Ply Membrane
Polyvinyl Chloride/Thermoplastic Olefin single-ply membranes belong to the other category of single-ply membranes known as thermoplastics. While thermosets retain their form once manufactured, thermoplastics are different in that they can be repeatedly softened and hardened with heating and cooling, respectively. They also require heat-welding to close seams, where tape and liquid adhesives would suffice for thermosets. There are several subcategories of thermoplastics, but the most common type is PVC/TPO.
PVC single-ply membranes are usually reinforced with fiberglass or polyester mats or scrim and contain stabilizers and plasticizers plus other additives to create a flexible material. Some can also come with non-woven fleece backing attached to the underside of sheets. PVC sheets are typically 45 to 90 mils thick and can be up to 12 feet wide. They come in numerous colors, with white and gray being the most popular choices.
TPO single-ply membranes, on the other hand, are a polyester-reinforced blend of ethylene propylene and polypropylene polymers. Depending on desired properties, they can be formulated to include colorants, UV absorbers, flame retardants and other substances. Like PVC membranes, they can made into sheets as wide as 12 feet, but they can be slightly thicker at up to 100 mils. They also commonly come in white.
Both are easy to install because of their single-ply design, although PVC is a bit more flexible to handle. In terms of lifespan, PVC membranes last about 20 to 40 years, while TPO sheets average 15 to 20 years.
4. Modified Bitumen
Think of modified bitumen as a cross between BURs and single-ply membranes, taking on the durability of the former and the installation ease of the latter. Made up of sheets of rubberized or plasticized asphalt with rolled reinforcing fabric, it is fastened to roof decks with cool adhesives or hot asphalt. Modified Bitumen systems are traditionally gray or black in color, but can be made more energy-efficient with white cool roof coating. Depending on preference, modified bitumen can be installed with surfacing or left smooth.
Aside from being easy to install and durable enough to withstand various weather conditions, modified bitumen is also easy to maintain and resistant to physical damage from outdoor threats. With a strong level of tear-resistance, it’s great for commercial roofs that see a lot of foot traffic, lasting an average of 20 years.
While metal roofing has a reputation for being an industrial or agricultural building material, it has grown in popularity as a residential roofing option. And as more and more homes are embracing metal roofing, more and more businesses are also opening up to it as a commercial roofing option, which is truly to their advantage.
Metal roofing is sleek, making it ideal for modern or contemporary structures. Still, it can complement traditional properties well, depending on how it is used. This is because metal roofing comes in a range of profiles and can be painted in any color of your choosing. It is also the only commercial roofing option that lends itself to both low- and steep-slope roofing, adding to its design flexibility.
Additionally, it is durable, shedding snow and rain well to help prevent moisture-related issues in areas prone to wet conditions, and won’t warp under extreme temperatures. Metal is a known heat conductor but it also has high emissivity, allowing it to easily lose what it does absorb to limit passive heating that can wreak havoc to a building’s energy efficiency. This makes metal roofing an energy-efficient option, ideal for hot climates.
Those concerned about metal roofing attracting lightning can also rest easy because that’s purely a myth. Metal roofing is at no more risk of getting struck by lightning than any other commercial roofing option because lightning strikes the highest point in an area. And if lightning does strike a metal roof, the danger is reduced because metal is extremely fire resistant. Overall, metal roofing’s durability gives it an average lifespan of 50 years.
Choosing the Best Roofing Option for Your Business
BUR, EPDM, PVC/TPO, modified bitumen and metal all have something to offer you as commercial roofing options. To help you zero in on the right choice for you and your business, don’t hesitate to get in touch with a re-roofing expert in Bellevue, WA, and the surrounding areas.