Back to top

Extending the Service Life of Warm Roof Build-Ups with Effective AVCL Technology

Firestone’s EPDM roofing membranes are used around the world to protect the building from water ingress, with many UK installations already demonstrating a trouble-free service life of 40+ years. In addition to protecting the roof build-up from external moisture, however, we also need to ensure that warm roof build-ups are protected from the risk of moisture rising from within the building, which is why Firestone has developed its latest generation of air & vapour control layer (AVCL) - V-Gard™. Why Do we Need an AVCL? The thermal performance of the buildings we construct has improved dramatically over the past few decades. The use of effective insulation materials and updates to building regulations have contributed to more thermally-efficient building envelopes. As we trap more heat inside the building to reduce the energy we need for a comfortable indoor environment, however, we also create the potential for moisture to rise to roof level. If this moisture is allowed to migrate through the roof build up, condensation can reduce the effectiveness of the insulation and, over time, the insulation could perish, compromising the integrity of the roofing system. A high performance AVCL like Firestone’s new V-Gard™ system is installed as part of the warm roof build up to protect the roof from moisture from within the building. It’s important because it: • Prevents condensation within the roof build up • Avoids the risk of damage to the insulation layer • Ensures the insulation delivers its designed performance • Contributes to the air-tightness of the building, which enhances thermal performance What is V-Gard™? V-Gard™ is the very latest AVCL technology from Firestone, developed specifically for use with any Firestone EPDM warm roof build-up and designed for ease of use and high performance. An aluminium foil with fibreglass reinforcement and self-adhesive backing, V-Gard™ features a unique film coating on the aluminium face of the AVCL which delivers exceptional adhesion for PU adhesives, ensuring a firm bond between the AVCL and the insulation layer. Indeed, the advanced technology used to create V-Gard™ ensures an effective and permanent bond between both the AVCL and the roof substrate and between the AVCL and the insulation layer. This, combined with V-Gard™’s superb vapour control performance, supports an extended service life for the entire roof build-up. When is V-Gard™ Used? V-Gard™ has been developed specifically for use as part of any Firestone warm roof build-up and its high vapour resistance means that it is suitable for even high humidity environments, such as swimming pools and leisure centres, along with residential buildings, offices, schools and hospitals etc. A flexible and durable membrane, V-Gard™ offers excellent resistance to foot traffic and is suitable even for installations where there is high mechanical stress. It is compatible for use on most roofing substrates, including metal, concrete and wooden decks. How is V-Gard™ Installed? V-Gard is a cold-applied, self-adhesive system which has been designed for ease and speed of installation, with excellent adhesion across a wide temperature range. Firestone recommends the use of SA-19 Primer directly onto the substrate to increase tackiness and avoid contamination from dust or debris. The V-Gard is then applied by peeling back the protective layer and applying the AVCL onto the roof, creating a firm and permanent bond with the substrate and at the laps. Overlap markings have been printed on both edges of the membrane for ease of installation. A PU adhesive should then be used to adhere the insulation layer to the V-Gard and Firestone recommends the use of ISO Twin Pack PU adhesive as part of a complete Firestone warm roof build up. Once installed, the V-Gard will provide temporary protection from rainfall for 3-4 days, enabling a part-installed roof to be left over a weekend, for example, and covered by the insulation and EPDM layers the following week.