Rubber Roofing Options: Comprehensive Comparison & Analysis

By far the most common type of roofing found in Calgary is a shingle roof — it's probably the one most people are familiar with. Shingles come in various flavours too, each suited to different budgets and situations. However, popular doesn't always mean the best, and there are many situations where a shingle roof is neither the best option, nor even possible at all.

Among the alternatives, rubber roofing offers an excellent blend of performance, longevity, and cost — but as with shingles, there are a number of types available. Unlike shingles, though, the various types of rubber roofing make a real difference to roof ownership.

Rubber roofing offers exceptional service in commercial applications. If you're thinking about a new rubber roof, it's important to know what options are available and what each one brings to the table — both the pros and the cons.

To begin to understand rubber roofing options, we start with the materials they're made from, and what each one offers.

Rubber roofing materials

There are four main types of rubber roofing materials on the market, each with its own attributes. These are:

EPDM roofing

What is EPDM roofing? EPDM stands for Ethylene Propylene Diene Terpolymer, a highly durable synthetic rubber. Used for flat and low-slope applications, it's available in several thicknesses and provides an incredibly robust roofing solution that offers long life and resistance to weathering, UV degradation, and ozone.

That makes it especially useful in variable climates like Calgary, where the wide range of temperatures has little effect on roof performance.

The material is offered in large sheets, bringing several advantages. Why does the size of the material matter? The larger the surface it covers, the more it minimises the number of seams in any application — and when installed correctly, it offers a completely watertight roofing solution. It also makes the install easier, with less seam to cover in any given job.

There are a number of ways EPDM roofing can be installed too — fully adhered, mechanically attached to the building, or even ballasted in some applications. Seams are either glued or taped, so there's no need for heating equipment during install, reducing safety risks.

However, no system is completely perfect, and EPDM does have some limitations. It isn't available in a variety of colours like some options, which may be important for branding. And while installation is relatively simple and fast, in roofs with numerous upstands and details that must be cut around, the install will be longer and more labour-intensive.

TPO roofing

What is TPO roofing? Another type of rubber roof material, TPO stands for Thermoplastic Polyolefin, and it's used as a single-layer roofing membrane with a number of advantages. It's becoming one of the most popular options for rubber roofing — the US-based National Roofing Contractors Association recently reported that its members are using TPO for as much as 40% of commercial roofing projects.

White in colour, it reflects heat — useful in the hot Calgary summer to prevent heat buildup in the roof space. In commercial applications, that can save on air conditioning costs over the year. The energy efficiency helps all year round, of course, and installation is relatively easy: TPO is either mechanically fastened or glued to the substrate with appropriate adhesive. Seams between sheets are welded together using a hot air gun, so no naked flames are required.

The combination of plastics and rubber in the TPO membrane makes it extremely durable, with good fire resistance. Because it's applied directly over a substrate — like boarded-over insulation — TPO is also an excellent material for use as an overlay to recover an existing failed roof. The cost-effective nature of the material makes this a popular approach.

TPO roofing can last as long as 20 years even in Calgary's harsh and diverse weather, but it's reliant on effective installation to get there. A failure to weld seams adequately can lead to premature lifting that shortens lifespan — so the choice of professional installer is particularly important here.

In addition, sheet width is restricted compared to other options, so there tend to be more seams in a TPO roof than an EPDM one, meaning more potential failure points.

PVC roofing

What is PVC roofing? Polyvinyl Chloride, otherwise known as PVC, is one of the more common plastics in use today. It's used to create a flexible, single-ply roofing membrane that's durable, chemical- and fire-resistant, and represents great value thanks to its long life.

That fire and chemical resistance — including being unaffected by greases and oils — can be useful in many commercial settings, and may be enough to make PVC roofing the right choice for many businesses. PVC is also simple to install: lightweight, easy to move around the building, and usually faster to fit than alternatives. The large sheets minimise the number of seams, which are welded together with hot air guns.

Durability matters, and PVC roofing isn't only long-lasting — it's also puncture-resistant, minimising maintenance needs across its longer-than-average lifespan. You may not need to replace this roof for well over two decades. It's also energy efficient: its white colour reflects UV rays and heat energy to help keep interior temperatures down, saving on cooling costs.

However, while these roofs can have a long lifespan, a PVC roof does need more maintenance and care than other options as it ages. From around 10 years in service, it'll need specialised maintenance for the remainder of its life.

For businesses in Calgary, one of the most important issues with PVC roofing is that it doesn't cope with significant cold spells as well as TPO or EPDM, so it isn't the best option for the local climate.

While easy and fast to fit, PVC roofing is usually a little more expensive overall for the total install too — although that can often be offset by the longer life between replacements. It's also not as easy to repair as other options, and because PVC can suffer from shrinkage issues, it'll be more demanding in terms of maintenance than a TPO or EPDM roof.

Modified bitumen roofing (SBS)

The final option for rubber roofing solutions is one you may not have heard of — so what exactly is modified bitumen roofing? For over 100 years, low-slope and flat roofing has featured built-up roofing systems based around alternating layers of asphalt and gravel. Modified Bitumen Roofing came as a development of that idea, first appearing in the 1960s. Instead of layers of asphalt, this new system uses a sheet membrane made from a combination of bitumen, polymers, and fibreglass — and it has been in use ever since.

That produces flexible sheeting that conforms to roof shapes more easily than some alternatives, making it a great choice for applications with odd shapes or lots of roof installations to work around. It's highly resistant to weather conditions, copes well with both high and low temperatures, and is a proven roofing system for use on low-slope or flat roofing projects.

Modified bitumen roofing is available in a range of thicknesses, with sheets including multiple plies for additional strength. That makes it a great option for areas that may see high foot traffic, and it's easily the most durable option for impact damage. It's also useful for repairing or overlaying asphalt-based roofing already in place, which can be problematic for other materials.

That thick, dark material does have some issues, though. It naturally absorbs heat, and in a Calgary summer it can contribute to a higher internal temperature than alternatives — with additional cooling costs that brings. It can also be slower to install than other options, and if you build several plies together for durability, cost can become an issue too.

Additionally, modified bitumen roofing is more vulnerable to water damage in situations where ponding occurs, and it requires the use of torches to install — which brings safety considerations as a result.

With four very different materials to choose from, the question is: which one is right for your building? We need to examine performance in a bit more detail to find an answer — beginning with durability.

Comparing the durability of each type of rubber roofing

Which is the best roofing? It sounds like a simple question, but the answer depends on the project and what your expectations are. One of the most important things to consider with a roof is durability — that is, how long it will last, how it copes with the environment, and so on.

Luckily, all these materials have been in use for years — and in some cases multiple decades — so we have a good idea of the lifespan for each. While they all offer 20 years of lifespan, that doesn't tell the full story of ownership. PVC roofing can require significant maintenance once it passes 10 years in service, and modified bitumen roofing has vulnerabilities — in particular ponding — that make it less durable in climates with high rainfall.

TPO roofing can be vulnerable to poor installation (which applies to all options), but with its simple adhesive-based seam sealing and robust material, EPDM provides the most dependable option for longevity in a diverse climate of both heat and cold, like the one we experience in Calgary.

Aside from lifespan, roofing today needs to be energy efficient to help manage the soaring costs of heating and cooling commercial premises.

Energy efficiency of rubber roofing solutions

With energy now a major cost for any business, the need for a roofing system that helps manage internal energy absorption and loss is more important than ever. Here, both bitumen and EPDM solutions fall short of the best — their darker colour means high heat absorption during summer, inflating cooling costs. Lighter-coloured PVC roofing reflects UV rays and heat energy to keep interiors cooler, and also provides good puncture resistance to maintain roof integrity. TPO does the same, but with better efficiency.

In terms of energy efficiency, then, the best option is TPO roofing — providing the best cooling effect during hotter weather, reducing the load on air conditioning systems, and lowering the energy costs of running those systems over the long term. But when looking at overall costs for your roof, we also need to examine the cost of the roof itself.

Cost considerations for your rubber roofing options

How much does a roof cost? When looking at a roof, we don't just need to think about the materials themselves, but also installation, maintenance, and how long it will last. For instance, if a roof costs half as much as another but only lasts a third of the life of the more expensive option, it's actually a higher-cost roof over time.

Our choices for rubber roofing do have different costs. Modified bitumen tends to be the more expensive option due to multiple plies and the labour-intensive installation process. PVC roofing is a little more expensive than the other two options, but can be quicker to install if that's important. Between the last two, EPDM will usually cost a little more thanks to a slightly more difficult installation process — with TPO usually offering the most competitive installed price for these roofs.

In terms of overall cost for the life of the roof, it's a similar story — however, with TPO lifespan being excellent, the cost difference between TPO and EPDM is usually small. We need to look at ongoing maintenance and repair options to see which is the best ownership experience.

Maintenance and repairs of your rubber roof

So which is the best rubber roof to own? While installation costs are crucial, ongoing maintenance also needs to be considered when understanding the costs and time investment for your new roof. Bitumen roofing offers highly robust impact resistance, but it does wear over time and is prone to damage from water through ponding — which is prevalent in climates with significant rainfall, like Calgary. Repairs are relatively easy, though.

PVC roofing requires extensive maintenance once the roof hits 10 years or more in service, as the material tends to shrink over time, causing issues. It's also the most difficult of these four options to repair, and so over the life of the roof it will require significant further investment.

TPO roofing has a great lifespan and is impressively durable and damage-resistant, with the major cause of issues being leaks along seams where welding hasn't been completely successful. EPDM has similar performance to TPO, but with its simpler, more reliable sealing and fastening options, it offers the least hassle for long-term ownership.

Conclusion

So which is the best rubber roofing option for you? That depends — each has its pros and cons when it comes to cost and efficiency. Some are better suited to particular environments than others, and which one is right for you will depend on all of these things.

There's no single "best roofing" option — instead, there are better options for your specific needs. That's why it's so important to take all aspects of roof ownership into account when choosing the right solution for your building. Take your time to understand the features, costs, and capabilities that matter most for your project, and select the rubber roof solution that's the best fit.