A flat or low slope roof assembly consists of several components that need to work together efficiently and consistently to offer a long-term, sustainable solution. While the roofing membrane is often the top and therefore most visible layer, what lies under it has a significant impact on the overall roof performance. Choosing the adequate and most sustainable materials (and ensuring their proper installation) is what makes a roof stand the test of time and be ready for the challenges of the future.
“A roof above one’s head” is the first line of protection against the elements. The primary role of a roof is protection against the elements, ensuring watertight security. Yet, modern roofing transcends mere functionality, aiming to be easy to install, maintain, and repair while also offering energy efficiency and environmental benefits. Sustainable construction practices amplify this concept. As a crucial component of a building's envelope, roofs significantly influence energy flow. The layering of a roof assembly aligns with its diverse functions, creating a substantial impact. Let’s take a look underneath the roofing membrane to discover a variety of possibilities.
Choosing the Right Roofing System
When opting for the right roofing system, things to consider may include questions such as: New or renovating project? Roof deck material? Weight capacity? Accessibility? Local climate and regulations? Green roof or solar panels? Rainwater management? Addressing these questions in the design phase will allow for the best fit.
In this context, Elevate roofing membranes offer a variety of installation options to meet the specific requirements of each project. They are installed in a single layer and without the use of flames, and are secured in place either using contact adhesives (fully adhered system), plates/bars and fasteners (mechanically attached system) or simply by a ballast layer such as river-washed gravel or pavers (ballasted system).
The Importance of Insulation
Insulation plays a very important role in sustainable construction. It is one of the most practical and cost-effective ways of making buildings more energy-efficient and keeping them cooler in summer and warmer in winter, which reduces heating and cooling costs. Proper thermal insulation is also one of the key requirements for passive buildings, a construction concept aimed at minimizing a building’s overall ecological footprint.
For flat roofs, the 'warm roof' concept prevails, placing insulation above the roof deck and under the waterproofing membrane. Common insulation types in Europe include PIR, PU, mineral wool, EPS, and XPS. Elevate's RubberGard EPDM and UltraPly TPO roofing membranes suit all these insulation types, offering varied installation methods. They adhere directly to PIR boards, however are not feasible with mineral wool, XPS, or EPS insulation. PIR boards excel in thermal performance as they are thin and light, and match the insulation value of thicker, heavier products.
What Are Cover Boards?
Cover boards are semi-rigid, relatively thin boards that are usually used between the insulation layer and the roofing membrane to provide added impact protection, separation and support. They are available in a wide variety of materials, such as PIR-based, gypsum-based, cement-based, wood-based, etc.
Including a cover board in the roofing assembly enhances the performance of the whole roofing system and helps it last longer. Although not yet very common in Europe, cover boards are particularly useful when the roof has additional functions, performs in extreme weather conditions (such as hail or heavy snowfalls) or is exposed to frequent foot traffic (for example during installation or maintenance works). This can potentially damage the insulation layer, resulting in reduced thermal performance, which would in turn cause an increase in energy costs. From a life cycle cost perspective, it is a smart move to protect the insulation layer with a cover board.
Compatibility of All Roofing System Components
The success of a roofing system relies on more than just the membrane. Primers, adhesives, fasteners, etc., are equally crucial for securing the roofing components, and their failure might jeopardize the entire system. Optimal performance therefore hinges on choosing compatible, reliable products that will last throughout a building's life.
At the end of the day, the key to the success of a roofing system is to choose the right products that are not only compatible but also guarantee its long-term performance. This means that each layer that is used under the roofing membrane matters, contributing together to the overall goal and function of the building project.