Twistfix

How to fit remedial wall ties in 3 easy steps

Remedial wall ties - Helical CD Tie

Description

Twistfix remedial wall ties are designed by Thor Helical.  They have twin-thread longitudinal blades with sufficient reactive interface angle to cut an accurate self tapping penetrative path into a wide variety of masonry elements when hammer-driven into brick, block, stone and concrete walls

Proven through independent testing programs and 25 years of use, helical wall ties are identified in B.R.E. Digest 329 (Table 5) as being suitable for use in all remedial situations, irrespective of the buildings substrate or its fire performance criteria.

The CD wall tie has a circumscribed diameter of 9mm and is typically driven into a tiny pilot hole to minimize disturbance to the masonry as installation proceeds at remarkable speed and great simplicity. The ties are:

  • Independently tested & CE Marked
  • Reliable in all types of masonry
  • Robust & corrosion free
  • Engineered upgrades of earlier helical ties
  • Patented in terms of helix consistency & driving configuration

Benefits

The mechanical interlock anchorage of the Twistfix helical wall tie exerts no expansive stress, does not rely on adhesion and is not affected by temperature extremes or fire.

The cross sectional profile of the spiral wall tie includes a wide portion, to maximise grip, and a narrow portion, to accommodate differential movements in all directions. The deep and continuous helical troughs prevent migration of water across the cavity.

When under load, the continuous helical blades interact with the host building material to impart an accumulative cone of stress at tangential angles to the helix. Loads are spread evenly along the full penetrative length of the tie to ensure reliability of connection in a wide variety of construction materials.

  • Rapid cost effective installation
  • Precise helical interlock anchorage
  • Combines axial strength with flexibility
  • Stable, reliable & unobtrusive

What makes the CD Tie superior to alternative Helical Ties?

Traditional helical wall ties are twisted by clamping one end of the wire & spinning the other (much like a rubber band on a balsa wood toy plane). The method develops a helix with a pitch that varies along its length. In contrast Thor Helical wall ties are engineered with advanced twisting die technology to accurately control the pitch of the tie. The advanced precise pitch of the Thor Helical CD Tie (Pat EP1307303) forms tightly mating threads within masonry to ensure a superior interlock performance.

A unique driving end arrangement (Pat GB2439633) permits safe, controlled and close-quarter installation of the CD Tie with low cost tooling. This allows the operator to maintain both hands on his drill during insertion, eases installation and eliminates the need for cumbersome and expensive telescopic setting tools.

What makes the CD Tie superior to alternative Helical Ties?

Fitting remedial wall ties in 3 easy steps

Fitting remedial wall ties in 3 easy steps

  1. DRILL pilot hole of appropriate diameter using a light percussive hammer drill. Stop drill rotating prior to drilling the remote wall layer to prevent ‘whipping’.
  2. Insert 9mm ø Thor Helical wall tie into SDS support tool and DRIVE the tie into the masonry using a lightweight roto-hammer drill.
  3. Once tool recesses the tie beneath the wall face FINISH by disguising entry bore with suitable filler compacted around the ties driving shank portion.

Product specification

Product: Thor Helical 9mm ø CD Tie

Lengths (mm): 180, 205, 230, 255, 280, 305 & 330

Material: Austenitic Stainless steel - (304 & 316)

Ultimate Tensile Strength: => 15kN

DECLARATION OF PERFORMANCE
(CONFORMS WITH BS EN 845-1:2013)
Substrate
Type
Substrate
Strength
(N/mm2 )
Pilot Hole
Diameter
(mm)
Tested
Embedment
(mm)
Cavity
Width
(mm)
Mean Load Capacity
(N)
Recommended
Tie
Embedment (mm)
          Tension Compression  
Aircrete (AAC) 3.5 0 85 225 1490 1500 85
Dense Aggregate Concrete 7 6 60 150 2870 2700 75
Common Brick 30 6 60 150 1940 2680 75
Perforated Brick 40 5 60 150 1990 2790 75
Structural Concrete C30 30 7 40 150 2370 2690 50

 

 
This installation video displays the wall tie installation process and demonstrates how self-tapping helical wall ties work.

Related links