Best-in-class resistance to hailstorms... to keep your roof dry
Summer thunderstorms with heavy rain and hailstones are becoming an increasingly frequent occurrence all over Europe. Large hailstones can cause significant damage to building envelopes, particularly to roofs. However, not every roof covering is able to withstand a hailstorm.
To deal with this eventuality, it is a smart move to fit a high-quality roofing underlay membrane that is resistant to hailstones directly underneath the roof covering. Underlay membranes protect the roof structure and insulation against the effects of the elements, and also act as a second waterproof layer in the case of damage to the roof covering, which can be caused by storms and hailstones. Membranes with integrated, verified hail impact resistance are a big advantage here!
Best-in-class hail impact resistance (HR5)
The inspection body for protection against naturally occurring hazards at the VKF/AEAI Association of Cantonal Fire Insurance Institutes in Switzerland has tested a range of pro clima roofing underlay membranes.
In these tests, the membranes are positioned on top of a wood-fibre insulating panel and this test structure is bombarded with hailstones. The membrane is then visually inspected for cracks and tears, and its integrity is tested with a water column of 10,000 mm (approx 32 feet). To pass the test, the membrane must still be able to support this water head.
The pro clima membranes that were tested obtained the highest possible hail impact resistance rating of HR5 (or HW5 in German): they were bombarded with the largest possible ice spheres (diameter of 50 mm or 2") at a speed of 110 km/h and remained intact and watertight.
Hail resistance as per EN 13583
The term hail resistance is used in the test procedure specified in the European standard EN 13583, which describes a similar testing method involving a polyamide (PA 6.6) sphere with a diameter of 40 mm (1" 5/8) and a mass of 38.5 g (1.4 oz.) impacting on the test structure. The lowest impact speed Vd in m/s that causes damage/perforation to the membrane is then determined.
Summary
Roofing underlay membranes from pro clima provide additional peace of mind: even if the roof tiles are damaged by hailstones, the pro clima membranes underneath will keep the structure below dry.
What's more, pro clima membranes can be exposed to the elements for period of up to 6 months.
