Retrofit Wall Ties

Thor Helical CD Ties have a circumscribed diameter of 9mm, a pointed leading end and a unique drive-shank end. The tie has a two-start helix thread, each having a precise twist accuracy. This patented wall tie replacement system offers cost-effectiveness and safe to use tooling. CD Ties conform to EN 845-1, meeting UKCA and CE Marking conditions for use as a tie for connecting cavity walls and a tension tie for solid walls.


Thor Helical CD Ties have a circumscribed diameter of 9mm, a pointed leading end and a patented drive-shank end.  The retrofit wall ties have a two-start helix thread each having a patented twist accuracy. When hammer-driven into small pilot holes the remedial ties corkscrew into brick, block and concrete to deliver a mechanical fix that grips the wall on each side of the cavity.

Unlike ties having expanding mechanisms, which deliver point-loadings when tightened, the threaded interlock connection of the self-tapping helical wall tie exerts no expansive stress into the brickwork and will not loosen with vibration.

The one-piece 9mm twisted ties have multiple drip points and are non-combustible.  The mechanical fixings require no resin or grout bonding agents. They are suitable for remedial use in all types of masonry and are particularly useful in overcoming low-temperature installations and material compatibility issues.  CD Ties conform to BS EN 845-1: 2013 for retrofit tying of cavity and solid walls to meet the conditions for UKCA and CE marking.

The Thor Helical CD Tie system is patented across four Continents. The retrofit wall ties have a unique driving shank that is engaged into a recessed SDS adaptor. The patented small diameter adaptor enables the tie to be aligned, driven and recessed in one simple operation.  This feature overcomes issues of safety and ease of use that may be encountered by earlier systems that use cumbersome, costly and unreliable telescopic tools.

Applications for the Thor Helical CD Ties include:

  • Wall Tie Replacement
  • Pinning Masonry Arches
  • Securing Solid Walls of Double-leaf or Collar-jointed Construction
  • Tying Rubble-filled Walls

Retrofit wall ties are supplied in cartons of 1000 pieces as standard; they can be packed in distributor-supplied boxes in bespoke quantities.


The Thor Helical 9mm ø CD Tie is available in a choice of AISI304 or AISI316 Austenitic Stainless Steel.  The remedial ties are supplied in standard lengths of: 155, 180, 205, 230, 255, 280, 305, 330, 355 and 450mm.


TYPICAL PERFORMANCE LOADS (taken from CE Mark Testing for retrofit wall ties)

Tension Compression
Brick 1.94kN 2.68kN 150mm
Perforated Brick 1.99kN 2.79kN 150mm
Aggregate Block 2.87kN 2.70kN 150mm
Concrete 2.37kN 2.69kN 150mm
Aerated Concrete 1.49kN 1.50kN 225mm



Product Attributes
Diameter 9mm
CSA 16mm2
0.2% Proof Stress >850N/mm2
Ultimate Tensile Strength* 1025-1225N/mm2
Mean Tensile Capacity # 17kN

* Ultimate Tensile Strength is measured within a calibrated tolerance of +/- 2%
# Mean Tensile Capacity is an indicative value derived from CSA x Mean UTS


TYPICAL PERFORMANCE LOADS (taken from CE Mark Testing for lateral restraint in the end grain of timbers)

BS EN 845-1:2013 National Annex NA states that the lateral needs to provide equivalent performance to the prescriptive 30mm x 5mm straps and the tension straps should have a declared tensile load capacity of at least 8kN.

Brick 215mm 5.61kN
C16 Timber – End grain 4.10kN

Ties are driven through a 215mm brick wall and into the end grain of a joist running perpendicular to the wall.  To meet this standard for lateral restraint straps installers must use a pair of 9mm ties in each joist-end.


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