HeliBars are bonded into cut slots at pre-determined levels in the masonry using HeliBond thixotropic cementitious grout, it is the composite action between the HeliBars and HeliBond that provides the core element of the Helibeam System, making it such a versatile, reliable and successful masonry repair system.
The length of the HeliBar varies depending upon the application. Longer lengths are used, normally in pairs, to form masonry beams that secure large areas of masonry, distributing the structural loads and overcoming various problems caused by foundation movement. They are also installed in the existing masonry to unobtrusively create or reinstate failed lintels. In shorter 1m lengths, HeliBars are used individually to perform reliable and permanent crack stitching.
HeliBar starts as round stainless steel wire with a typical 0.2% proof stress of 500N/mm² but after the cold forming manufacturing process that creates the helical hi-fin design, this more than doubles to around 1100N/mm². This means that HeliBar, with its relatively small diameter, provides substantial tensile properties to the masonry, particularly when combined with HeliBond grout which locks between the fins and bonds to the masonry. Consequently, the well proven Helibeam System has a variety of remedial and new build applications.
- Crack stitching
- Lintel repair and creation
- Forming deep masonry beams
- Horizontal structural restraint (when used with BowTie systems)
- Reconnecting separated walls
- Securing parapet walls
- Support existing masonry when creating new openings
- For reinforcing new build masonry
- Creating movement joints
- Seismic upgrades for existing masonry
- Repairing bridges, tunnels and arches
- Austenitic stainless steel helical bars
- Combines great axial strength with flexibility
- Accommodates differential building movement
- No additional stresses introduced into structure
- Generates high tensile strength with mortar(new build only) or HeliBond grout
- Extremely economical compared with alternative methods
- May remove or reduce the need for mass underpinning
- Fully concealed once installed
- Avoids expensive taking down and rebuilding
- Minimal disruption to building’s fabric or occupants
- Spreads structural loads to avoid secondary cracking
- Reduces the potential for cracking in shrinkable materials
- HeliBar to be long enough to extend a minimum of 500mm either side of the crack or 500mm beyond the outer cracks if two or more adjacent cracks are being stitched using one rod.
- Where a crack is less than 500mm from the end of a wall or an opening, the HeliBar is to be continued for at least 200mm around the corner and bonded into the adjoining wall or bent back and fixed into the reveal, avoiding any DPC.
- For solid masonry in excess of 225mm thick and in a cavity wall where both leaves are cracked, the wall must be crack stitched on both sides.
- If there is render/plaster, this thickness must be added to the depth of slot. Crack stitching must be installed in the masonry and never in the render.
- Ensure the masonry is well wetted or primed to prevent premature drying of the HeliBond due to rapid de-watering, especially in hot conditions. Ideally additional wetting of the slot should be carried out 1 to 2 minutes prior to injecting the HeliBond grout.
- Do not use HeliBond when the air temperature is+4°C and falling or apply over ice. In all instances the slot must be thoroughly damp or primed prior to injection of the HeliBond grout.