A roof is just a roof, right? Something to cover your head and keep the tenants, assets, or whatever else is inside safe and dry? How different can a commercial roof be from a residential roof, other than the types of structures they’re built on?
The reality is that commercial roofs and residential roofs are wildly different from one another, beyond just their usage or size. Yes, one roof type is designed for commercially used buildings while the other is designed to stylishly cover your head at night, but the differences between them -- from slope, materials, installations, and maintenance -- run far deeper. There is no one-size-fits-all roof for any particular building type, so our comparison of commercial and residential roofs is more about highlighting trends than establishing back-and-white rules.
Strange as it may seem, there can in fact be commercial roofs on residential buildings. But unless they’re installed by certified commercial roofers, they’re likely not the most integrally sound or professionally installed commercial roof option. That, however, is only the tip of the roofing iceberg. Below, we dive into all of the major distinguishing factors of each roof type to better understand what defines them and how very different they are.
SLOPE: Low vs Steep
A commercial roof is any roof that’s installed on a structure built for commercial use, but more specifically, it tends to mean a “low slope” roof. They’re also commonly known as “flat roofs,” but that’s not completely accurate since they still require some small angle to efficiently shed water.
A residential roof, as you may have guessed, is the roofing system above your home designed for residential use. Residential roofing refers to the installation of roofing products on a customer’s home, garage, or other residential structure. These products are generally designed for “steep slope” applications and normally include shingles to aid in efficiently shedding water.
Sometimes a residential property can have both a steep-sloping section and a low-sloping section.
Residential roofing usually deals with steep-sloping structures while using shingles made of asphalt, slate, wood, or synthetic plastic. The shingles are further classified by being economy grade, architectural style, designer style, or heavy-weight. More recently, solar shingles have been popularized and are slowly making their way into the market as well.
Generally speaking, the materials for residential roofs are far more varied because they’re designed and constructed with aesthetics as a priority. Customers want a variety of material and color options to choose from. Residential roofs will be almost entirely based on the homeowner’s personal preferences regarding appearance, as well as durability, life expectancy, and required maintenance.
On the other hand, commercial roofing usually deals with low-sloping structures while using membrane rolls such as modified bitumen (asphalt), EPDM (rubber), or TPO (plastic). The roofing materials chosen for commercial buildings often have far less to do with aesthetics and more to do with the function of the building itself. If, for example, the roofing needs to be able to withstand the weight of heavy machinery and the heat from its discharge, then the material used needs to match those parameters.
And for every roofing rule, there seem to be some exceptions!
Built-up roofing, better known as BUR, as well as modified bitumen roofs are sometimes used on low-slope residential roofs. Proof that you can use any flat-roof material on any flat roof building and vice versa, whether the building is used for residential or commercial purposes. However, the usage of the building itself is ultimately the deciding factor and there are advantages and disadvantages for every roofing type.
Residential roofs are usually structured by A-frame trusses, plywood, decking, and shingles for the roof itself. There are accessories that fit between the plywood decking and the roofing shingles such as roofing felt, leak barrier, and drip edge. For the most part, residential roofs take a day or two to install using ladders and, depending on the slope, workers are usually strapped using ropes and fall-protection harnesses.
Commercial roofing installations are much larger and require significantly more planning, manpower, equipment, material, and expertise. Commercial work requires precise roofing services performed by skilled crews who have a deep knowledge and understanding of the products they sell and install. At most, residential roof installations only need to work around a chimney. Commercial roofers need to factor in external piping, drainage, HVAC units, satellites, airflow systems, and any number of other intrusions.
Most commercial roof types require dangerous industrial equipment and highly-trained contractors with specialized skill sets to perform the work safely, accurately, and to a very high standard. Issues like water drainage and equipment penetrations are more common, expensive, and time-consuming hazards compared to residential roofs. That’s why the installation of drainage points, gutters, and other water mitigators on commercial roofs is an essential part of their much more involved installation process.
REPAIRS & MAINTENANCE
Shingled steep-slope roofs are less prone to leaks thanks to their lack of seams. Their angular construction also means that ponding water issues common on commercial roofs are virtually never a hazard. Likewise, in the winter, steep-slope roofs excel at snow disposal compared to low-slope roofs, which often require that you hire someone to actively remove any snow. The common enemies of residential roofs are wind or “nail pops” that cause individual shingles to dislocate or break over time. These are considered the most common reasons shingled, steep slope roofs need repairs.
For economy-grade shingles you can expect the roof to last 10-15 years before needing maintenance. For architectural shingles and above, you can expect them to last 30-50 years before needing maintenance.
A commercial roof’s arch nemesis is ponding water, an ever-present threat due to its lower, “flat” slope and more numerous drainage points. Commercial roofs, overall, require a higher attention to detail and greater level of ongoing care, including routine maintenance to clear its drainage points, checking for penetrations caused by equipment or other contractors, and identifying leak vulnerabilities or standing water issues. Commercial roofs require routine maintenance and bi-annual inspections to ensure they operate at their best and keep their warranties in good standing. If maintained properly, they can often last for 30 or more years.
At the end of the day, the biggest differentiator between commercial and residential roofs boils down to this: if a shingled roof is poorly installed, chances are it still won’t leak. If a low slope roof is poorly installed, you can pretty much bet on it leaking.
Commercial roofing contractors and residential roofing contractors are very different people.
Put simply, there’s a higher bar of entry to be qualified as a commercial roofing contractor. The commercial roofing community is populated by a specialized labor force uniquely qualified to handle the more involved, high-risk, and large-scope work. Commercial building owners require more evidence of a contractor’s qualifications, insurance, training, criminal records, and drug testing. There are also fewer opportunities for corner-cutting and more protocols in place to ensure accountability, quality, and safety.
Residential roofs are traditionally lower-risk than commercial roofs, so it’s easier for a residential contractor to get away with being less reputable or qualified. It’s also the reason “Pete and a truck”-type contractors are almost always residential roofers. Residential roofers often don’t have the experience, equipment, or time management expertise to perform commercial roofing work to the highest possible standard.
And the same goes for commercial roofers trying to do residential work as well! At the end of the day, they are two very different worlds.
Aside from the work, commercial and residential roofs are also differentiated by the type of clients the respective contractor is working with.
Commercial roofers deal largely with private or public buildings owned by individuals with a long list of requirements and much more at stake than the dryness of their heads. They’ll be determined to review certifications, secure permits and licenses, cross-check contractors qualifications, and ensure their contractors are adhering to every OSHA protocol.
Residential roofers will deal with a completely different, often private, customer base. Naturally, residential contractors have different methods for selling their services and appealing to a completely different audience. After all, they’re communicating with an entirely separate demographic versus the private or public building owners or managers of larger commercial structures.
It might be easy to think of a roof as just a roof and that the only distinction between commercial and residential roofs are their size. But as you can see, there are a number of major differences between the two, including their usage, structure, material, installation, and contractors.
They share a common interest: covering your head. But beyond that, commercial roofing and residential roofing are two wildly different worlds with vastly different considerations, sizes, and requirements.