Repair Failed Cavity Wall Ties
Stainless steel helical remedial ties to restore structural integrity to failing cavity walls — a cost-effective alternative to rebuilding.
The Problem
Wall tie failure generally occurs due to insufficient ties being installed during construction, or their deterioration due to corrosion. Rust causes expansion of ties, leading to cracking of masonry — ultimately leaving a façade wall vulnerable to wind loads and structural failure.
In either case, replacing cavity wall ties with corrosion-resistant Stainless Steel Wall Ties provides a robust and lasting remedial solution — without the disruption and cost of demolishing and rebuilding.
Thor Helical Solution
Thor Helical's Stainless Steel Wall Ties are installed using the CDT-DRIVER — an efficient, cost-effective self-tapping and non-disruptive mechanical anchor used when resin or neoprene expanding ties are unsuitable.
Key Features
Product Specification
Ø8mm available in 170–320mm · Ø9mm available in 180–380mm · Both in 25mm increments
Standards Compliance
- ✓ BS EN 845-1:2013+A1:2016
- ✓ PD 6697:2019
- ✓ BS EN 846-6:2012 (test method)
- ✓ Eurocode 6 (EN 1996-1-1)
- ✓ UKCA & CE Marked
Ø9mm Cavity Width Selection Table
| Product Code | Tie Length (mm) | Brick to Brick/Block | Brick to AAC | Brick to Concrete |
|---|---|---|---|---|
| CDT-0180-A2 | 180 | 1–25 | — | 31–50 |
| CDT-0205-A2 | 205 | 26–50 | 0–30 | 56–75 |
| CDT-0230-A2 | 230 | 51–75 | 46–55 | 81–100 |
| CDT-0255-A2 | 255 | 76–100 | 71–80 | 106–125 |
| CDT-0280-A2 | 280 | 101–125 | 96–105 | 131–150 |
| CDT-0305-A2 | 305 | 126–150 | 121–130 | 156-175 |
| CDT-0330-A2 | 330 | 151-175 | 146–155 | 181-200 |
| CDT-0355-A2 | 355 | 176-200 | 171–180 | 206-225 |
| CDT-0380-A2 | 380 | 201-225 | 196–205 | 231-250 |
Ø9mm Performance in Various Substrates
| Substrate | Comp. Strength (N/mm²) | Cavity Width (mm) | Min. Embedment (mm) | Pilot Hole (mm) | Mode | Ultimate Load (N) | Tie Type | Design Load (N) |
|---|---|---|---|---|---|---|---|---|
| AAC | 3.5 | up to 225 | 85 | Not Required | Tension/Compression | 1490 / 1500 | Type 3 | 496 / 500 |
| Dense Aggregate Concrete Block | 7 | up to 150 | 65 | 6 | Tension/Compression | 2870 / 2700 | Type 1 | 956 / 900 |
| Fletton Brick | 30 | up to 150 | 65 | 6 | Tension/Compression | 1940 / 2680 | Type 2 | 646 / 893 |
| Perforated Brick | 40 | up to 150 | 65 | 5 | Tension/Compression | 1990 / 2790 | Type 2 | 663 / 930 |
| Structural Concrete C30 | 30 | up to 150 | 40 | 7 | Tension/Compression | 2370 / 2690 | Type 2 | 790 / 896 |
Wall Ties tested as performance guidance. On-site pull-out tests are required to evaluate substrate-specific performance. Depending on substrate material, on site testing may be necessary to determine the most appropriate size of pilot hole and inner leaf embedment depth to provide optimum balance of performance in each leaf.
Ø8mm Remedial Cavity Wall Ties — Test Results (Brick substrate)
| Product Code | Tie Dia. (mm) | Tie Length (mm) | Cavity Width (mm) | Min. Embedment (mm) | Pilot Hole (mm) | Mode | Ultimate Load (N) | Tie Type | Design Load (N) |
|---|---|---|---|---|---|---|---|---|---|
| M82-0170-A2 | 8 | 170 | 0–15 | 65 | 6 | Tension/Compression | 2340/1390 | Type 2 | 780/463 |
| M82-0195-A2 | 8 | 195 | 16–40 | 65 | 6 | Tension/Compression | 2340/1390 | Type 2 | 780/463 |
| M82-0220-A2 | 8 | 220 | 41–65 | 65 | 6 | Tension/Compression | 2340/1390 | Type 2 | 780/463 |
| M82-0245-A2 | 8 | 245 | 66–90 | 65 | 6 | Tension/Compression | 2340/1390 | Type 2 | 780/463 |
| M82-0270-A2 | 8 | 270 | 91–115 | 65 | 6 | Tension/Compression | 2340/1390 | Type 2 | 780/463 |
| M82-0295-A2 | 8 | 295 | 116–140 | 65 | 6 | Tension/Compression | 2340/1390 | Type 2 | 780/463 |
| M82-0320-A2 | 8 | 320 | 141–165 | 65 | 6 | Tension/Compression | 2340/1390 | Type 2 | 780/463 |
Installation Guidance
Drill Pilot Hole
Using percussion drill and masonry drill bit, drill through outer leaf into inner leaf. Stop drill in cavity to prevent whipping.
Drive the Tie
Insert nubbed end into CDT-DRIVER. Drive into both leaves using lightweight hammer drill until fully embedded in outer leaf.
Patch & Finish
Patch the pilot hole of the recessed tie with mortar to conceal the retrofit repair.
Thor Helical Additional Accessories
Ø9mm CDT Remedial Wall Tie
Self-tapping mechanical anchor — the premium remedial tie. Non-combustible, no resin needed in most substrates. Available 180–380mm in 25mm increments.
Ø8mm Remedial Wall Tie
High-performance tie for tight or standard cavity walls. Available 170–320mm. Type 2 in brick. CDT-DRIVER installation method.
CDT-DRIVER Installation Tool
Dedicated SDS adapter tool for driving remedial cavity wall ties. Included in installation kits. Compatible with standard SDS hammer drills.
8mm Teletool – Remedial Wall Tie Installation Tool
SDS Tool for driving 8mm Double Pointed remedial cavity wall ties. Compatible with standard SDS hammer drills. (Also available for 12mm Double Pointed Ties)
Downloads
Full technical data, test results and installation guidance
TH Remedial Cavity Wall Ties
Ø8mm and Ø9mm ties - repair of cavity walls suffering from cavity tie failure