For businesses in any industry, one thing remains the same: people need a roof over their heads. Repairing or replacing a roof is no small task. It can be costly, but an important one that will protect the building your business is in. The cost of this job depends on a variety of factors. To better understand what a commercial roof replacement entails, we’ve compiled all the variables that will affect the cost of a new installation. A commercial building needs a roof that covers a lot of square footage; as such, it can run a high price to replace. Here are the factors that will alter the cost of your new commercial roof:


Is your roof accessible?

For areas that are more difficult to reach or walk across, a greater cost will be involved. Your commercial roof is likely either flat (low-slope) or sloped. Flat roofs are easier to access, but if your building is tall, the contractors might need a crane to transport materials. If your roof is sloped, it may be unsafe to walk on; contractors will need to rent additional equipment to install a new system, such as scaffolding or a man lift. Height is another factor to consider - conveyance equipment may be required for especially high roofs to move the crew and materials, like a passenger hoist. The area surrounding the roof will factor into the cost, as workers will need space to store their materials and equipment nearby.

If the commercial space is occupied during the installation, the contractors will face additional challenges. They have to take into account the health and safety of people within the building while they are working. In some cases, they may need to install the system outside of regular working hours. 


What size is the roof?

The square footage that must get covered may be the single biggest factor in determining the overall cost. It will decide the volume of materials that are required. For larger roofs, there may be a build-up of debris and removal costs will influence the overall price. Roofs larger than 20,000 sq. feet have one advantage - the cost of the job begins to scale down after this size, which saves you money per square foot. Yet for jobs of this magnitude, there may be a fee for transporting materials up and across the roof. Finally, for roofs that require extra materials, there is the added cost for moving them to and from the site.


What are the conditions of your current roof?

Depending on how damaged your existing roof is, certain preparations may need to be taken so that the new system adheres properly. Components that will change the price of a new roof installation are the substrate materials, structure, the cover boards, the insulation, and the underlying roof structure. Extensive water or impact damage will bring up the cost significantly. Infrared technology can be used to assess the moisture levels within the structure. There are a few different courses of action that your contractor will take when assessing the condition of your current roof:


If the roof needs additional support, then recovery boards will be secured to the top of the existing roof as this makes the application process easier. Depending on the climate your commercial building is in, fasteners may be required to withstand powerful wind loads.

Your contractor may need to remove or strip your existing roof. This is the result of one of two reasons - the roof is too damaged or unstable, or your building already has two roofing systems. In the latter case, one system will need to be removed before another is installed. Several factors affect the cost of stripping and removing your current roof. These include the height, size, and depth of the system; bigger roofs that are higher up with thicker ply will be more expensive to strip.

The best-case scenario is that your current roof simply needs some cleaning before the project begins. This route is the least costly because it doesn’t involve any major alterations. The surface will need to be prepared to ensure that new materials will adhere to it. Air pressure cleaning can be used to remove dirt from the top layer of your roof. A wet vac will eliminate any dust, gravel, or debris, and a dry vac will remove any rocks embedded in the surface. Deeper cleaning is achieved using a power washer to remove ballast and make the existing roof spotless. 


Which insulation will you use?

The right type of insulation can save you on heating and cooling costs. Usually, two layers are installed so that your roof has sufficient protection and does not allow heat to escape. Depending on your needs and the climate of your area, you may opt for different types of insulation: 

One of the most commonly used materials is Polysio (polyisocyanurate). Its rigid foam board structure is highly energy efficient. This firm material is durable, long-lasting, and has a higher R-value than other types of insulation. R-value refers to the thermal resistance of a roof - in other words, how well it can hold up to the heat or cold. This tends to be the most expensive option.

Are you searching for a more economical type of insulation? You might consider EPS or expanded polystyrene. It’s the least costly of the three types of insulation but has a lower R-value. This material is made of lightweight foam plastic and is compatible with most roofing systems used in commercial buildings. It provides savings in energy costs, is moisture-resistant, and stable. This insulation is environmentally friendly; EPS is not manufactured with harmful gases that deplete the ozone layer, such as HCFCs or CFCs. It can be used on flat or sloped roofs. 

Finally, there is extruded polystyrene or XPS. This material is a bright colour, like green, blue, or pink. It costs less than Polysio, but more than EPS, and it has a moderate R-value. It has great compressive strength and is very adaptable to any roofing project; it can be installed on nearly any system using all methods of application. XPS is highly water-resistant and has channels on each edge to allow water to drain out, protecting the structural integrity of your roof. It will not mould, which gives it long-term durability. For those looking for a middle ground when it comes to insulation options, XPS may be perfect for your building. 


Which membrane will you have installed?

To prevent leaks, your roof will need a waterproofing membrane; there are different options available at different price points, however, basing your decision on price alone is not advisable. Waterproofing membranes should be selected based on building design and function. The advantages and disadvantages of each membrane are detailed below. Things to consider when selecting a membrane are the height of your building, the roof traffic, amount of wind and rainfall in your area, and your aesthetic preferences. 

For single-ply roofs, there are three membranes to consider. The first is TPO (thermoplastic polyolefin). It’s a popular and affordable choice for commercial spaces because it is suitable for covering flat roofs. TPO has been in use for roughly 20 years and is made of a synthetic scrim that reinforces the system. It reflects sunlight, which is why some people call it a “green roof”; its ability to reflect heat saves you on energy costs. Thermoplastic polyolefin is chemically attached to the insulation to ensure a strong bond. It can be made in a variety of colours including tan, grey, white, or a specialty shade of your choosing. The seams are fused with a hot air gun which creates an air-tight finish. When this membrane is maintained well, it can last 15-20 years.

The next membrane is a flexible material made of synthetic rubber. It has been a popular choice since 1960, and has stood the test of time - it typically lasts 20-25 years. It’s called ethylene propylene diene monomer or EPDM.  This material retains heat from sunlight and is attached mechanically instead of chemically. It is available in black or white. Seams are fused using a specialty tape. Unlike TPO, this finish can be ballasted. 

Yet another option is PVC or polyvinyl. It’s a high end membrane that is more costly than other options, yet its chemical composition makes it more reliable and leak-resistant. When it’s installed by experienced contractors, this roof can last 20-30 years. Similar to TPO, this membrane reflects sunlight; its efficient properties can save your business as much as 30% in energy costs. The seams are welded using hot air to prevent moisture from damaging the membrane. 

Finally, there’s modified bitumen SBS membranes, a 2-ply system that uses a synthetic asphalt-based technology. This membrane has flexibility in a wide range of temperatures. Its thermal resistance gives it longevity and durability. The fibreglass reinforcement in the material used makes it both stable and elastic. The strength of bitumen is enhanced by the use of a polyester mat, which allows for movement and gives it resistance to tears, punctures, or water leaks. This membrane is ideal for flat or low-sloped roofs and supports all methods of installation, from mechanical fastening to adhered attachment. 

If your roof has a slightly higher slope and is not completely flat, you can do away with membranes altogether and have a metal roof installed instead. They can easily shed rainwater and snow to keep your building safe from water damage. During storms, metal roofs can withstand impact. They have a lifespan of up to 50 years as long as they are properly maintained. To enhance their cooling properties, you can opt to apply a reflective coating. When installing a metal roof, it’s important to hire reliable contractors - any open seams can allow water to damage the structure underneath. 


What is the method of installation?

After you’ve selected a membrane, the next step is to choose which method of installation is suitable for it. There are three different methods. Each one carries a set of pros and cons concerning the cost, ease of installation, and endurance:

Fastened attachment is a mechanical way of securing the membrane - it functions best in roofs that are flat or sloped, and has great resistance to strong winds. It involves metal plates and screws that are inserted into the seams of the sheet. Materials like steel or wood take well to the screws as anchors to the membrane. 

Adhered attachment with a one or two part adhesive will bond to the membrane without penetrating it, reducing the opportunity for any leaks. Its smooth surface is aesthetically pleasing, and the colour of the membrane can be customized to suit the building. Adhesives can be asphalt, water-based, or solvent-based. The chemical attachment is strong enough to withstand the force of the wind and can be installed in either flat or sloped roofs. 

Ballasted attachment is the least expensive option, but the most difficult to maintain. Many prefer the look of this method; it involves covering the underlying membrane with materials like river rock, gravel, or pavers. It requires a roof that can withstand the weight of these materials. Ballasted attachment is ideal for flat surfaces; if the slope is too steep, it will cause problems. Areas with high wind loads can affect the structural integrity of the bond. The challenge with this method is that in the event of a leak or other roofing issue, the ballast must be removed to inspect.


What type of warranty option will you pick?

At Transcona Roofing, our contractors offer a 5-year Roofing Contractors Association of Manitoba (RCAM) warranty to make sure that you are protected. If you desire an extended warranty with broader coverage, manufacturers offer additional product or system warranties depending on the materials installed. A manufacturer’s product warranty comes at a lower cost but covers the waterproofing layer on the roof, typically only factory defects. A manufacturer’s full system warranty is more inclusive and lasts longer, but comes at a higher expense.


Does your roof have penetrations?

Additional accessories can affect the cost of a roof replacement. These include products like skylights, air vents, air conditioning units, and plumbing vents. Your roof may have solar panels installed on it. These features create additional work for contractors. It means that the membrane has to be modified to fit these protrusions instead of being laid out as a straight sheet. The material is cut to size, which takes more time for the contractors and therefore, costs more. 


We hope that this guide will help you estimate the cost of your commercial roof replacement. This task requires a great deal of knowledge and experience. It’s an investment that will protect your business for years to come. Many contractors may claim to be experienced for a roof replacement, however, it is important to make sure you find someone who is qualified to do the work and can provide warranties once complete. Remember that the lowest price may not be the best option. Repairs will cost you more down the line than saving a few hundred dollars for a less expensive installation. For a job of this scale, you’ll want to hire honest roofers who are up for the task. The professional contractors at Transcona Roofing have the certifications and experience to keep your business protected for years to come.


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