
Bituminous hot melt systems have emerged as a popular choice for green roofs and inverted roofs due to their unique advantages. In this blog, we’ll show why combining Soprema DUOFLEX and SOPRA XPS is ideally suited for these applications.
As a bituminous hot melt system, DUOFLEX and SOPRA XPS together provide a robust and long-lasting solution, ensuring that the roof remains leak-free even under constant exposure to moisture. It’s also an excellent solution for inverted roofs because of its compatibility with various types of insulation materials – and it’s flexible enough to be customised for the specific needs of a project. Inverted roofs can sometimes have ballast or pavers on top, so bituminous hot melt systems are sufficiently robust to withstand the weight and pressure of added components without experiencing cracks or damage.
Key advantages of DUOFLEX and XPS
DUOFLEX creates a durable, monolithic barrier that has self-healing properties. Because it never fully cures, water can’t track under the system even if the waterproofing is punctured.
What’s more, our bituminous hot melt system is ideal for phased works. Roofing contractors can complete penetrations and details first, allowing other trades to finish their work before applying DUOFLEX to the main roof areas.
DUOFLEX saves time and reduces gas consumption because it melts faster than other hot melt products. DUOFLEX also doesn’t need costly neoprene strips at junctions; instead, installers can use ELASTOPHENE FLAM 180-25 for reinforcement. This ease of application makes DUOFLEX well suited to waterproofing large areas.
Best of all, the system is easy, fast and cost-effective to apply. DUOFLEX comes in solid 20kg blocks that are ready for on-site melting and require only a limited investment in terms of equipment.
Meeting building and sustainability regulations
DUOFLEX structural waterproofing systems are classed as unrestricted according to building regulations in relation to BROOF(t4). SOPRA XPS is a BREEAM A-rated insulation material, approved by the Green Guide to Specification. SOPRA XPS SL, SOPRA XPS 500 and SOPRA XPS 700 have received a Bronze Cradle to Cradle Certificate. In addition to its sustainability credentials, the SOPRA XPS range boasts excellent compressive strength, reliability and durability.
When used as an upstand insulation material, XPS needs a cementitious facing. At Soprema, we are also able to supply ready-to-install SOPRA XPS upstand boards with factory-applied cementitious facing.
How to combine DUOFLEX and SOPRA XPS on green roofs
DUOFLEX and SOPRA XPS are often combined on inverted roofs, including green roofs. The insulation is installed on top of the hot melt layer and finished with slabs or ballast. The SOPRA XPS boards shield the waterproofing membrane from plant damage and mechanical damage, as well as enabling foot traffic (for green roof maintenance, for example).
In addition, a DUOFLEX and XPS system is ideal for sites with podium areas, which contractors can then use as a loading bay. After applying the hot melt, XPS is installed on top. This means contractors can unload construction materials onto the area without puncturing or damaging the waterproofing.
SOPRA XPS has a Euroclass E rating; combined with DUOFLEX and a ballasted finish, the system can be installed on any part of a roof without restriction of boundaries, and there is no risk of flames spreading from one building to another. For applications such as irrigated roof gardens, green roofs, blue roofs, and brown and biodiverse roofs, a fire test is not always needed once installers follow the guidelines in Annex of Commission Decision 2000/553/C.
Under normal service conditions, DUOFLEX provides an effective barrier to the transmission of liquid water and water vapour for a roof’s designed lifetime.
Get in touch
Want to find out more about our solutions, the technical services we offer, or to discuss how to incorporate Soprema systems in a specific functional roof project? Don’t hesitate to contact our technical experts who can provide all the necessary inspections and training for projects where DUOFLEX and XPS is the system of choice.