RESTORING THE PAST, CONSERVING THE FUTURE
BowTie
For restraining bowed walls
BowTie is a long stainless steel tie used to stabilise bulging walls, without any external plates, by securing them into the ends of internal floor joists.
BowTie HD is a heavy duty 12mm diameter threaded bar with self-cutting end used to restrain bowing building walls by securing them to internal parallel floor joists or roof beams.
System Components
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Drill bit for clearance hole
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BowTies
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Power support tool
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HD Driver
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Hand support tool
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PolyPlus resin cartridge with extension nozzles and applicator
Installation
1. Mark the position of the joist centre on the external wall and then drill a clearance hole (normally 12mm) through the wall (and first joist if parallel to the wall). Clean out the hole
2. Fit the BowTie Support Tool to an SDS rotary hammer drill, insert the BowTie and drive it into joist end to the required depth – at least 75mm (or through the second joist if parallel)
3. Fit the plastic sleeve over the BowTie and use the support tool to push it to the back of the hole in the masonry (in the outer leaf in a cavity wall)
4. Inject PolyPlus resin to fill the hole and bond the BowTie to the masonry and then make good
BowTie HD
1. Mark the position of the joist centre on the external wall and then drill a clearance hole (normally 16mm) through the wall. Clean out the hole
2. Fit the BowTie HD Support Tool to an SDS rotary hammer drill, insert the BowTie HD and drive it (off hammer) into, and through, the first and second joists
3. Fit the plastic sleeve over the BowTie HD and use the support tool to push it to the back of the hole in the wall (outer leaf in a cavity wall)
4. Inject PolyPlus resin to fill the hole and bond the BowTie HD to the masonry, allow the resin to gel and then make good
Applications
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For stabilising bowed external building walls by securing them to internal floor and ceiling joists
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Standard BowTies are recommended when installing into joist ends
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BowTie HDs are recommended when installing into joist sides
CemTie
Grouted tie for stabilising solid masonry
CemTie is a versatile, fully grouted, remedial tie used to stabilise all forms of solid masonry, secure failed lintels and brick rings, reconnect separated internal and external building walls and repair parapets.
System Components
- CemTies of different lengths
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Manual applicator and two extension nozzles
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Long series drill bits
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Brush for cleaning hole
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HeliBond cementitious grout
Installation
1. Drill clearance hole to required diameter and depth and flush clean
2. Push CemTie fully into grout-filled pinning nozzle of grout gun and insert nozzle to the back of the hole
3. As grout is injected the CemTie is carried with it
3. As grout is injected the CemTie is carried with it
Applications
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Lintel repairs
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Securing multi-layer brick rings in bridges, tunnels and arches
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Reconnecting separated internal and external building walls
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Securing delaminated masonry
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Repairing and securing parapets, cornices and decorative fascias
DryFix
Dry mechanical pinning and remedial tying system
DryFix is a versatile and rapidly installed mechanical pinning and remedial tying system that requires no resin, grout or mechanical expansion.
Other types of the DryFix tie are available for specialist applications. For securing delicate terracotta fixings Helifix offer the DryFix Terracotta, for securing loose render there is the DryFix RenderPin and for securing a soft outer leaf material to a hard inner leaf material is the DryFix Asymmetric.
System Components
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RP Drill bits for drilling pilot holes (where necessary)
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Load Test Unit and Pull Test Key
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Special Power Driver Attachment for rapid installation
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Power Driver Extension (where necessary)
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DryFix tie
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SDS Drill for installation
Installation
1. Drill small pilot hole using rotary percussion drill, 3-jaw-chuck type
2. Load tie into DryFix Power Driver Attachment fitted to SDS hammer drill
3. Drive in tie until outer end is fully recessed below face of masonry
Applications
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Versatile replacement wall tie
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For securing multiple layers of masonry
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For pinning delicate masonry features
Crack Stitching
The most efficient way to repair structural cracks
Helifix Crack Stitching repairs and stabilises cracked masonry using stainless steel HeliBars bonded into cut slots with HeliBond grout for a quick, simple, effective and permanent solution.
Cracked masonry is best stabilised by bonding HeliBar stainless steel bars into appropriate bed joints or cut slots. Tensile loads are redistributed along the masonry to minimise further developments of the crack which may occur with simple injection methods.
Technical Details
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Available diameters – 4.5, 6 and 8mm
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Available in lengths of 1m, 1.5m and 2m
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Material – Austenitic stainless steel
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Vertical spacing – Every 4-6 brick courses (300-450mm)
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Depth of slot – Single skin / cavity wall 25-35mm Solid masonry 25-40mm
System Components
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1m lengths of HeliBar
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HeliBond cementitious grout
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Mortar rake
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Mixing paddle
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Applicator with fitted applicator nozzle
Installation
1. Rake out or cut slots into the horizontal mortar beds, a minimum of 500mm either side of the crack, to the specified depth.
2. Clean out slots and flush with clean water and thoroughly soak the substrate within the slot.
3. Using the CS Pointing Gun Kit, inject a bead of HeliBond to the back of the slot.
4. Using the HeliBar Insertion Tool, push the HeliBar into the grout to obtain good coverage.
5. Insert a further bead of HeliBond over the exposed HeliBar, finishing 12mm from the face, and ‘iron’ firmly into the slot using the HeliBar Insertion Tool.
6. Re-point the mortar bed and make good the vertical crack with Crackbond TE.
Repairing Cracks Near Corners & Openings
Where cracks are less than 500mm from an external corner or an opening, for example a window, at least 100mm should be bent around the corner and bonded into the return wall or bent and fixed into the reveal, avoiding any DPC membrane.
Where two or more cracks are close together these may be stitched using one continuous length of HeliBar which must be long enough to extend 500mm beyond the outer cracks. e.g. if there are three cracks, each 250mm apart, then the overall length of HeliBar required would be 1.5m.
The horizontal slot, normally the mortar bed, can be cut using a twin diamond blade chaser with vacuum attachment, an angle grinder or a mortar chisel.
All mortar must be removed, together with any loose debris, to ensure a sound bond. Prepare the slot with HeliPrimer WB or thoroughly wet the slot with clean water.
As standard, slots should be 10mm wide to accommodate the 6mm diameter HeliBar.
HeliBond grout is the recommended bonding agent. PolyPlus resin is used for smaller jobs and where loads are to be rapidly applied.
Additional Advice
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Where two or more cracks are close together these may be stitched using one continuous length of HeliBar which must be long enough to extend 500mm beyond the outer cracks. e.g. if there are three cracks, each 250mm apart, then the overall length of HeliBar required would be 1.5m.
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The horizontal slot, normally the mortar bed, can be cut using a twin diamond blade chaser with vacuum attachment, an angle grinder or a mortar chisel.
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All mortar must be removed, together with any loose debris, to ensure a sound bond.
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Prepare the slot with HeliPrimer WB or thoroughly wet the slot with clean water.
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As standard, slots should be 10mm wide to accommodate the 6mm diameter HeliBar.
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HeliBond grout is the recommended bonding agent. PolyPlus resin is used for smaller jobs and where loads are to be rapidly applied.
Helifix Drilling & Testing Guide
Masonry drilling guide
For all remedial ties it is extremely important to use the correct drilling technique to avoid excessive spalling of the near leaf as the drill breaks through into the cavity. Cases have been identified where up to 80mm of the brick thickness have been broken off, bridging the cavity and leaving insufficient material to make either a chemical or dry connection.
Wherever possible rotary percussion drilling should be used with 3-jaw-chuck type drills. This may increase drilling time but damage to the brickwork will be greatly reduced. With the DryFix range, rotary percussion masonry drills should be used as standard to ensure the accuracy of the hole’s diameter and to avoid appreciable spalling.
Rotary Percussion Drill (3 Jaw Chuck Type)
Where rotary hammer drill bits (SDS type) are used, the size of the drilling machine should be as small as possible and the operator must not lean on the drill as this reduces its effectiveness and increases the likelihood of spalling.
Rotary Hammer Drill
​Where drilling through the brick face is not acceptable then it will be necessary to consider inserting the remedial ties through the mortar bed. This will be satisfactory where the mortar is strong and in good condition. Angled drilling may also be used in special circumstances.​
Wall tie spacing and testing
Pre-specification testing should be included as a routine part of the building survey. At least one, and preferably two, ties should be inserted into each elevation at different levels to determine the minimum pull out load obtainable from both the near and far leaves.
This minimum load should be used as the basis for deciding the density of ties to be installed. For a small contract at least 10 ties must be tested; on large projects 5% of all ties should be tested.
For most applications (buildings under 30m high and areas with a maximum wind speed of less than 46m/sec) the minimum tensile proof load is 1kN based on a tie density of 2.5 per m² (900mm x 450mm centres). This excludes cladding form masonry and substrates below 100mm deep. For applications outside these criteria please consult either the Helifix sales team or BRE Digest 401, January 1995.
Part E Acoustic Performance – Helifix 6mm and 8mm diameter wall ties have been independently tested for dynamic stiffness and comply with the sound insulation requirements of Building Regs, Part E for a Type B tie.
