Rising energy costs make flat roof energy efficiency a smart investment. With the right energy-saving strategies for flat roofs, landlords can reduce operating costs, improve occupant comfort and qualify for tax incentives and green certifications from Canada Green Building Council/LEED and other green building organizations. In this article, you’ll learn how to improve your roof’s energy efficiency, significantly reducing heating and cooling costs, extending the roof’s lifespan and contributing to sustainability goals.
Flat roof energy efficiency opportunities vary, but the principles remain the same
Landlords and roofers must balance many factors when considering flat roof energy-efficiency options. These include upfront costs, long-term ROI, local climate, local building codes and more. A good place to start when evaluating energy-saving options is the opportunities and challenges of new construction versus roof renovation.
New construction
New construction offers the greatest opportunity to plan for flat roof energy efficiency. Project engineers can optimize energy efficiency using an integrated approach that encompasses all infrastructure and systems.    Â
Roof renovations
Renovations also provide opportunities for flat roof energy efficiency. However, there are more limitations. The roofer must work with existing infrastructure and systems such as windows and electricity. This makes it harder to estimate future energy savings resulting from the optimized roof alone.  Â
Here are two important questions when considering flat roof energy efficiency:
An upgraded roof can certainly improve roof performance and longevity. But how will it affect energy savings? You can ask these two questions: First, which energy-saving opportunities will best meet the landlord’s goals? Second, how significant a difference will even the most energy-efficient roof make? It’s not always an easy calculation.
How to boost flat roof energy efficiency
For any flat roof, energy efficiency can include several strategies. Stakeholders should explore the methods below to determine which will provide the most energy savings and align with overall project goals.
 Now it’s time to explore options for making your new or existing roof more energy efficient.
1. Conduct a flat roof energy efficiency audit before renovation
What’s the first step? Conduct an efficiency audit to locate under-performing areas, such as poor insulation or abandoned penetrations. This information allows you to set realistic goals, prioritize upgrades and calculate potential energy savings.
2. Improve insulation for better flat roof energy efficiency
Roof insulation is perhaps the most critical factor affecting flat roof energy efficiency. The basic tips are to:
- Install high-R-value insulation, a measure of how well a material resists heat flow.
- Add or improve rigid insulation boards that meet or exceed ASHRAE and local code R-value standards.
- Don’t re-use wet or damaged insulation.Â
- Wrap HVAC units, curbs and ductwork with appropriate thermal insulation.
3. Seal air leaks, roof penetrations and perimeters
Poor seals lead to energy waste and thermal performance. To help ensure flat roof energy efficiency, roofers should:
- Inspect, seal, flash and insulate roof penetrations, vents, curbs, skylights, drains and equipment on the roof.
- Remove any abandoned penetrations and close the substrate openings to maintain air-tight seals
- Ensure continuity of the air barrier at roof-to-wall transitions, penetrations and seams.
- Review the building envelope details for uninsulated cavities in wall assemblies, knee walls, and parapets.
4. Improve rooftop drainage to aid energy efficiency
Poor drainage reduces insulation performance, causes ponding and otherwise creates energy loss. Make sure to:
- Ensure proper slope and consider adding tapered insulation.
- Add, repair, or replace drains and scuppers as needed.Â
- Incorporate automatic heat tracing for cold climates.
- Track performance and minimize energy use with smart heat cable systems with sensors and timers.
5. Use energy-efficient flat roof membrane materials
Each of the membrane types below offers a different set of pros and cons, including how well it aligns with the project’s flat roof energy efficiency goals.
- Built-up roofing (BUR): BURÂ includes insulation layers for a higher R-value, especially with a ballast layer. Instead of a dark protective coating, use lighter pea gravel or reflective white calcite chips.
- Modified bitumen: Modified bitumen is a flexible, durable material that combines asphalt, polymerized rubber/plastic and fiberglass. It reflects sunlight and reduces heat absorption, resulting in decreased energy costs. Manufacturers also offer coatings that reflect sunlight, reduce heat absorption and reduce cooling load. Consider using white reflective granules with higher SRI ratings instead of the other available colours.
- Single-ply membranes: Single-ply membranes in light colors help optimize energy savings by resisting UV rays. Look for certification from Energy Star, CRRC or other efficiency rating organizations. Note that single-ply membranes need insulation added, with choices varying by cost, performance and R-value. Talk to your roofer about your options, along with the pros and cons of each for flat roof energy-efficiency.
6. Choose light-colored or reflective rooftop surfaces
Lighter roofing membrane, ballast and/or coating colors and higher reflectivity can reduce rooftop temperatures and lower cooling loads. Another option is applying reflective roof coatings, such as acrylic, silicone, elastomeric or polyurethane.
7. Boost flat roof energy efficiency by upgrading skylights
A piece of glass is never as energy efficient as a roof substrate with proper roof insulation. That said, two ways to increase skylight energy efficiency are to:
- Replace old skylights with double-glazed, low-E argon units to improve insulation.
- Ensure air sealing and curb insulation with proper one sided gasket tape.
8. Integrate solar panels if structurally feasible
Solar PV panels can generate electricity and help reduce energy costs. Whether or not to add solar PV depends on structural capacity, incentives and other factors. Even if solar PV isn’t installed now, consider adding solar-ready features like reinforced mounting zones and electrical pathways.
9. Install a green roof
With a green flat roof, energy efficiency includes special advantages. It acts as natural insulation, protecting the roof membrane, reducing the heat island effect and improving stormwater management. Requirements include a heavy load-bearing structure, accessible maintenance and a roof slope under 5o for extensive systems.
10. Flat roof energy-efficiency methods require ongoing maintenance and inspectionsÂ
Regular maintenance and inspections help ensure that small problems don’t grow into larger, more costly ones. Keeping your roof in top shape can help optimize flat roof energy efficiency.
Perform timely repairs to maintain energy efficiency Â
Ongoing maintenance improves the overall health and longevity of your roof. It will also keep flat roof energy efficiency methods in place. Call a roofer immediately if you spot leaks or signs of moisture. These may indicate problems affecting energy efficiency, such as damaged insulation, poor drainage or unsealed penetrations.
Ensure maximum efficiency with twice-yearly roof inspections
Many problems remain hidden under the roof’s surface and won’t be seen in a simple visual inspection. Scheduling a twice-yearly professional roofing inspection with a high-quality contractor like Elite Roofing and Contractors will further ensure that hidden problems related to energy efficiency are detected.
Optimize flat roof energy efficiency with a qualified roofing contractor
Explore opportunities for better energy efficiency when planning your new roof construction or renovation project. Contact a trustworthy, experienced roofing contractor who can provide expert advice on energy-saving roofing strategies. Partner with Elite Roofing and Contractors to optimize your building’s energy efficiency and return on investment. Get the #EliteAdvantage.
