Commercial Roofing
Most commercial buildings are flat roofed because of the cost-effectiveness involved with roofing large areas. Depending on the building type and the budget, the building’s expected lifespan, and other factors, you could be looking at single-ply membranes, built-up felt roofing systems, or even a liquid-applied coating. There is a time and place for every roofing system. What works for a refitted office block may not work for a factory with heavy plant equipment on the roof.
Larger commercial projects are increasingly utilising single-ply membranes such as TPO and PVC. The sheets provide wide membrane coverage, and are welded at the site creating a seamless coating to reduce weak points. TPO (thermoplastic polyolefin) is quite common, and a great choice for roof accesses used for maintenance because it’s durable and reflective which help with cooling costs in the summer. PVC membranes are a little more expensive and have been around for a longer time with a proven track record. On small commercial buildings, such as shops, offices, and light industrial units, the EPDM rubber membrane works great. The EPDM rubber membrane is flexible, relatively quick to install, and can handle most weather challenges. Depending on the application, the sheets can be either bonded or mechanically fixed. While it is not as heat-reflective as the TPO, it is a solid workhorse material.
A more traditional approach is the Built-up roofing (BUR) method. It includes layers of felt that are bonded with hot bitumen and topped with mineral chippings or a cap sheet. While more labour intensive than the single-ply systems, it creates well over the foot traffic a building can handle. It is often the first choice when refurbishing a building because of the BUR that is overlaid to the roof rather than stripping it back to the deck.
For refurbishing buildings, awkward details, and over most current roofing, liquid-applied membranes are gaining traction. This approach eliminates the need for a complete strip-out and the building can remain fully operational. They are cold-applied, which is safer as there is no hot work involved, which is especially crucial when working on buildings that are flammable, or contain a lot of electrical material. There are no weak points for water to infiltrate, offered by the seamless finish.
The majority of industrial and agricultural buildings use metal roofing. There are many systems that may work best for your building, including standing seam systems, composite panels, and profiled sheeting. With metal, one advantage is the speed of installation. When trying to make a building weather-tight, that is essential. There is also a fully composite panel which uses metal skin over foam insulation. This also simplifies the build up and provides decent thermal performance.
Beyond aesthetics, commercial buildings that use green roofs also fulfill several other functions. For example, green roofs help to manage the surfaces that collection water runoff, which is a requirement for planning departments. The insulation also provides value by cutting heating and cooling costs. Some local authorities offer better business rate discounts on buildings that have green roofs. The main challenge green roofing provides is the weight and making sure the structure can handle the additional weight.
Construction of warm roofs is now standard for newly built commercial buildings. The insulation is below the waterproofing and above the deck so that the deck stays at a stable temperature. This prevents condensation. The distribution of the vapor control layer is crucial. If done poorly, moisture gets trapped in the build up, which leads to rot and insulation failure.
It makes sense to have maintenance contracts for commercial properties. Regular inspections can catch minor problems before they become major issues. A blocked gully or a split seam can be fixed for a few hundred pounds. Leave those problems until water is pouring into the building, and you will be looking at thousands in repairs, plus the costs to fix the damage the leak caused on the inside.
Access and safety become more important on commercial roofs. Proper edge protection, safe access routes, and sometimes permanent anchor points for fall arrest systems are needed. Health and safety regulations are more strict for commercial work, and for good reason. Working at heights is dangerous, and larger roof areas increase the potential for accidents.
Warranties usually run for 10-20 years depending on the system and whether it’s a new roof or a refurbishment. Getting the right specs for the expected building lifespan is important. There is no point in fitting a 20-year system on a building with only 10 years of economic life left, but you also don’t want to be re-roofing a new warehouse after 15 years because you initially went cheap.