Insofast Ltd
Insulation Fixings
Structural Repair
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Plasterboard Insulation Fixing

General Quick Guide

  • Fire-proof mechanical fixing for plasterboard insulation
  • Quick & easy to use
  • Dependable performance
  • Countersinks without tearing
  • Dished head retains filler
  • Highly versatile in a wide range of construction materials
  • Fixes plasterboard to light-weight block without pre-drill
  • Fixes to concrete block & brick with tiny
    pilot hole


A one piece metal fastener with a dish profiled head for mechanically securing drywall and insulated plasterboard panels to walls. Prevents dot and dab plasterboard from falling on persons escaping a blazing building, or on persons entering a blazing building for rescue purposes.

The fire-proof metal fastener has a self-tapping helical shank with work hardened blades able to cut into a wide range of masonry. Hammer in with a rubber mallet or with an SDS adaptor in a light-weight drill set at slow speed on hammer only action.




ISF18A fixings are suitable for use with all types of insulated drywall boards. They can be used in conjunction with dot and dab adhesive (3 per board) or in place of it (12 per board), to ensure stability of the boards in the event of a fire.

Cold bridging is minimised thanks to a thermally efficient spiral shaft that has a cross sectional area just 25% of that of a solid shaft of equal diameter. Also by virtue of a fully countersunk head, which indents into the gyproc layer without tearing.

The plasterboard fixing drives directly into Aircrete (Celcon, Thermalite, etc.). Use 5mm pilot hole for fixing in brick, concrete or concrete block.


Product Specification

Material Zinc Plated 1008 Steel
304 Stainless Steel
Diameter of Head 18mm - (2.5mm dish)
Diameter of Shank 7mm
CSA of Shank 9mm≤
Typical Load @ 1mm Defln Aircrete 649N
Brick 622N
Softwood 681N
Typical pull through 12.5mm Plasterboard 340N
9.5mm Plasterboard 255N
Embedment Depth Aircrete 50-75mm Brick/Block 40-60mm
Softwood 35-50mm
Available Lengths* 65mm, 85mm,
105mm, 125mm
Page updated 11th Mar 2014, 09:25
© Insofast Ltd
KKM Buildings
Old Reservoir Road
Company No. 07455797, Registered in United Kingdom
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