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5 most common roof coverings for commercial buildings

Most commercial buildings have flat or low-sloping roofs, compared with residential buildings which tend to have pitched roofs. This is because flat roofs are more cost-effective, easier to install and can be used as storage space for equipment. Flat roofs, however, can suffer harsher effects from bad weather, are more costly to install and require more maintenance. That’s why it’s important to ensure you choose the right roof covering for your building and business needs.

Let’s look at the main, most commonly used types of commercial roofing systems.

1. Single ply

Single ply systems are easy to install and long-lasting. Single ply membranes, usually synthetic polymers, come in a range of thicknesses, colours and materials that are lightweight, waterproof and durable. They can also mimic other, more expensive materials, such as metal.

Single ply is thermally efficient when combined with insulation, offering a flame-free, robust solution which is very resilient in bad weather. Membranes are in a single, flexible sheet so they can cover complex-shaped roofs well and are safer to install because they can be welded with hot air. They are very versatile and can be used as a foundation for additional design features, such as roof terraces and balconies. They can also form the base for green roofs (see type 5), becoming a component of more environmentally friendly roofing systems.

Take a look at Vue Cinema in York. We recently refurbished the roof, installing a strong, durable single ply system with a 20 year guarantee.

2. Metal roofs

Metal roofs are lightweight, easy to install and are available in a wide range of finishes and colours. They are low pitch and particularly useful in situations where it’s important to have vandal-resistant roof finishes. Metal roof cladding, sheeting or tiling materials can be designed in tune with surrounding roof designs and there are three types to choose from.

Standing seam designs, with raised seams using concealed fasteners, are versatile, flexible and particularly good for curved roofs. Prefabricated composite panels of two, bonded metal skins, give a quick, low maintenance solution. Twin skins are similar but are assembled on site and provide two layers of metal sheets, separated by a metal spacer grid. This allows a very hardwearing, long lifespan of up to 25 years. Metal roofs offer three durable solutions to fit a range of design needs.

At Sankey Bridge Industrial Estate, where Warrington Borough Council needed to enclose an asbestos roof without disturbing it, we used insulated steel sheeting to overlay and encapsulate it safely. This is a good example of the varied use of metal roofs – in this case, giving the safest, most cost-effective solution with enhanced insulation.

3. Built up felt systems

Built up systems, also called Reinforced Bituminous Membranes (RBM), use felts with very high tensile strengths. Despite their strength, they are flexible enough to expand and contract well. They also offer excellent thermal values.

There are two construction methods for RBM – hot and cold. The hot method involves bonding the felt to the surface with a gas torch and the cold method fixes the felt mechanically, or bonds it with hot air and adhesives. Both have advantages. The hot method ensures a quick, robust solution and the felt is an integral part of the surface. The cold method is preferable in more lightweight projects, particularly where safety must be prioritised, without the use of gas torches.

Our work at Newchurch Primary School demonstrates exactly that situation. The school needed a new, felt roof with good energy conservation, in a hardwearing, long-lasting finish. We applied the felt using the cold method to prevent fire risk, providing a roof which is durable and long-lasting.

4. Liquid applied roofs

This is a liquid-based coating of polyurethane, which bonds with the substrate to form a waterproof membrane. Since it is applied cold, there are no associated risks with hot works, so it can be used in myriad situations. It can be applied to a wide range of material bases – from asphalt to steel – and has many advantages. It is quick and easy to apply, seamless, hardwearing and long-lasting and requires little maintenance. Liquid waterproofing is used, not just on roofs, but for basements, terraces, bridges, wet rooms and many more applications and is an excellent solution to use in complex designs and difficult situations. It is a versatile, highly elastic system with strong adhesive qualities, high UV resistance and excellent energy efficiency. All in all, a product with numerous benefits and applications.

5. Green roofs

Green roofs are popular due to their huge benefits and natural design possibilities. They significantly help the environment by increasing biodiversity and carbon capture and reducing pollution and the urban heat island effect, whilst building a roof that provides good soundproofing and excellent visuals.

The full advantages are many and varied – increased water capture and reduced flooding, reduced noise, better air quality due to the planting of flora and improved roof life expectancy. Plus, there are many additional benefits linked to the green roof design itself. Roofs can be designed and used for leisure purposes, such as seated relaxation areas and other amenities. Designs can incorporate solar solutions and they can be created to merge into and complement their surrounding environment to maintain a more natural look. Green roofs are also proven to aid our psychological and physical wellbeing.

An example of a green roof we have delivered is Stockport Grammar School’s new educational space for its pre-reception class. Working with Bauder, we fitted the living green roof as part of a remit to provide a design that links the inside with the outside and enables more outdoor and sensory learning. The green roof and building architecture was designed to blend with the school’s landscaped spaces and natural feel.

There are many factors that should be considered when selecting the right roof covering for your commercial building. At CRS, we always take the time to fully understand your business needs and operational requirements, so that we can advise the best roofing solution for you.

Get in touch if you have any questions or need advice – we’re always happy to help.


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