Retrofit timber-frame wall ties are thin helical wall ties used for wall tie replacement in timber-framed buildings of up to 4 stories high. The ties have a nominal diameter of 5mm and a tiny cross-sectional area of just 6.25mm2, making them the most flexible helical wall tie on the market. The flexibility is required to accommodate differential movement between the timber frame and the brick façade.
It is not uncommon for existing timber-framed buildings to have insufficient or incorrectly fitted cavity wall ties. In such cases, these retrofit stainless steel helical ties offer a practical and straightforward wall replacement tie solution.
To install the timber-framed remedial ties, one must accurately locate the upright studs. Using an SDS setting tool, drive the ties 35-45mm into the uprights of the frame via a clearance hole that extends through the outer leaf and sarking board. The ties will corkscrew into the wood, providing a secure mechanical connection. Bond the brickwork end of the tie into the bed joint using a pumpable class 2 mortar or resin equivalent. The continuous deep-trough helix ensures a good key for the mortar and multiple drip points to prevent water transfer across the cavity.
Fixing stainless steel timber ties requires ancillaries, including a 10mm SDS drill bit, blow pump, mortar or resin, and a mortar-applicator gun.
Remedial timber-framed wall ties are available in cartons of 2500 pieces in bags of 250. They can be obtainable in distributor-supplied boxes in bespoke quantities.
- Suitable for wide cavities – up to 150mm.
- Copes with 24mm differential movement even in narrow cavities (60mm)
- Patented precise pitch engineering delivers a helix consistency with unrivalled performance.
- Thor Helical timber frame wall ties conform to BS EN 845-1 and conditions for CE marking according to Annex ZA.1. They also meet the requirements for a Type 6 tie for cavity widths ranging from 60mm up to 150mm.
The 5mm ø timber frame wall ties are grade AISI304 Austenitic Stainless Steel. They are available in standard lengths of:
- 205mm ties – 60-80mm cavity
- 230mm ties – 85-105mm cavity
- 255mm ties – 110-130mm cavity
PERFORMANCE LOADS 60-150mm cavity (taken from CE Mark Testing)
||Type 6 Tie
Loads at 24mm differential movement to reflect timber shrinkage
TYPICAL MECHANICAL PROPERTIES OF THOR HELICAL TIMBER TIES
|0.2% Proof Stress
|Ultimate Tensile Strength*
|Mean Tensile Capacity #
* Ultimate Tensile Strength is measured within a calibrated tolerance of +/- 2%
# Mean Tensile Capacity is an indicative value derived from CSA x Mean UTS