fixing external wall insulation with Insofast fire resistant anchors

Thor Helical manufacture fire resistant fasteners for fixing external wall insulation systems to the outside of buildings. These metal EWI fixings ensure the stability of insulating boards and fire-breaks, in the event of a fire.

There has, for some time, been concern about fire performance and flame-spread of external thermal insulation cladding for walls of multi-storey buildings or of buildings close to boundaries. BRE Guide 135 recommends a suitable fixing method is required to ensure the system will not collapse in a fire. Where external wall insulation systems are being used on buildings of 3 storeys and over, at least 1 fixing per square metre must be fire resistant. Similarly fire resistant fasteners should be used to support the fire-breaks. These fixings should be in addition to the specified fixing rate for plastic mechanical fixings.

The ISF35 is a fire resistant anchor that is available in a choice of stainless steel and zinc plated carbon steel versions. It has been designed for anchoring insulation boards to masonry of concrete is fire-sensitive situations, including fixing external wall insulation and securing overhead insulation to concrete ceilings. The ISF35 anchor has a high performance 7mm diameter helical shank, which fixes to brick block and concrete and a 35mm diameter perforated head that clamps the board to the backup material. The fastener offers good pull out performance in a range of masonry materials to resist wind suction loads.

The metal EWI fixing is driven into brickwork via a 4.5mm to 5mm pilot hole; a 6mm hole is needed for structural concrete. When hammer-driven, work hardened helical fins cut diametrically opposed groves into the masonry as the anchor corkscrews in.  This delivers a mechanical anchorage with a constistent level of reliability and performance. Use a 5mm hole for brick or concrete block. To fix simply drill the pilot hole and hammer the fixings in using a series of light blows. A handy SDS hammer-drill adapter is available for fixing external wall insulation at greater speed and with reduced labour.

Standard lengths available: 110mm, 145mm, 170mm, 200mm, 225mm and 250mm

Thor Helical external wall insulation fixings are supplied in cartons of 400 and packed in bags of 20.

What makes the Thor Helical concrete soffit fixing a cut above the rest?

  • Fully fire resistant mechanical fixing – 100% metal fastener with no plastic components
  • 10mm2 helical shank for reduced cold bridging
  • Contact area just a fraction of that offered by tubular fixings
  • High performance = less fixings, less labour and less cold bridging
  • Highly versatile in a wide range of construction materials
  • Small pilot hole for minimal detritus
  • Rapid SDS hammer insertion