Masonry Pinning & Arch Repair
Restrain outer façades, pin masonry arches, tie rubble-filled walls and secure quoins — without bonding agents in most substrates.
The Problem
Older masonry structures can develop defects such as bowing façades, separating arch layers, unstable quoin stones, and detaching rubble-filled wall leaves. These issues may require restraint solutions that can perform across varied substrates and in sub-zero conditions.
Applications
Masonry Arch Pinning (Dry-Fix / Grout Fix)
Pinning masonry arches with reinforcement bars increases resistance to tensile loads and reconnects separated arch layers or keystones, improving load capacity.
Tying Rubble-Filled Walls (Grout Fix)
Older rubble-filled walls can bow or bulge due to rainwater penetration or freeze-thaw cycles. Heavy Duty bars connect inner and outer layers of old stone together.
Heavy Duty Masonry Pinning (Dry-Fix)
Fixing outer facades to party walls or perpendicular partitions. Bars grip brickwork along their entire length — a mechanically fixed tension strap.
Securing Quoins (Dry-Fix / Grout Fix)
Quoin stones at building corners fixed with Heavy Duty Helical bars to add strength at external intersections, preventing them from rotating or separating.
Key Features
Product Specification
- Standard Duty: Ø9mm
- Heavy Duty: Ø12mm
- Ø9mm lengths: 430–610mm (25mm increments)
- Ø12mm lengths: 610–1370mm (150mm increments)
- Ø9mm material: Grade 304 SS (316 on request)
- Ø12mm material: Grade 316 SS
Test Results
Masonry Pinning — Tension Test Results (Brick 30N/mm²)
| Bar Diameter (mm) | Substrate | Min. Embedment (mm) | Pilot Hole (mm) | Mode of Test | Mean Load @ 2mm (N) | Ultimate Load (N) |
|---|---|---|---|---|---|---|
| 9 | Brick (30N/mm²) | 215 | 6 | Tension | 3006 | 5610 |
| 12 | Brick (30N/mm²) | 215 | 8 | Tension | 4510 | 8450 |
Masonry Pinning — Shear Test Results
| Bar Diameter (mm) | Substrate | Pilot Hole (mm) | Offset Shear (mm) | Mode of Test | Ultimate Load (N) |
|---|---|---|---|---|---|
| 9 | Brick (30N/mm²) | 6 | 10–12 | Shear | 3453 |
| 12 | Brick (30N/mm²) | 8 | 10–12 | Shear | 6710 |
Grout Ties — Poor Substrate Conditions
When masonry condition is poor, WHO-60 Grout bonds helical bars to the weakened substrate via a Ø18mm clearance hole. Grout Ties can reconnect external walls with internal partitions, stabilise parapets, and pin arch layers in buildings, bridges and tunnels. Grout Ties can reconnect external walls with internal partitions, stabilise parapets and pin masonry arch layers in buildings, bridges and tunnels. Masonry Pinning bars can be installed into a Ø18mm clearance hole with WHO-60 Grout to bond the Helical Bars to the weakened substrate, restoring strength to the separating masonry. Grout Ties are available in Ø8mm and Ø9mm as standard.
Grout Ties — Performance Data
| Bar Diameter (mm) | Min. Embedment (mm) | Mode of Test | Mean Load @ 2mm (kN) | Ultimate Load (kN) |
|---|---|---|---|---|
| 8 | 400 | Tension | 8.00 | 11.06 |
| 9 | 400 | Tension | 8.45* | 11.50* |
Note: *UKCA Marking Only
On-Site Pull Testing
Laboratory test results serve as performance guidance only. On-site pull-out tests are essential to evaluate substrate-specific performance and determine the appropriate pilot hole size and embedment depth for optimum connection in each leaf.
When drilling pilot holes in weaker substrates, it is advised to use percussion drilling. When using an SDS Rotary Hammer action drill on weaker substrates, there is potential to rupture the inside surface of the masonry, which will reduce the effective embedment depth available to the tie.
When installing a pilot or clearance hole through the cavity into the inner leaf, drilling should be paused when inside the clear cavity, preventing a 'whipping' action of the drill bit and to prevent the misalignment of holes.
Percussion Drilling produces a clean bore in weaker substrates · Rotary Hammering can cause spalling and reduce effective embedment depth in the masonry
Also Used With
Ø9mm Masonry Pinning Bar
Standard duty helical pin for masonry arch pinning, façade restraint and quoin fixing. Self-tapping in sound substrates. Grade 304 Stainless Steel.
Ø12mm Heavy Duty Pinning Bar
For heavy façade restraint, tying rubble-filled wall leaves, and fixing large quoins. Grade 316 Stainless Steel. Longer lengths up to 1370mm.
Grout Ties (WHO-60 + Ø18mm clearance hole)
When substrate is poor — bond bars via clearance hole with WHO-60 grout. Suitable for bridges, tunnels and weak masonry. 8 or 9mm bars embedded 400mm minimum.
Thor Helical Grout Gun
Used with different nozzles to install grout for different applications. A flattened nozzle is used for applying grout to bed joints and a pinning nozzle is used for filling clearance holes with grout. When installing grout into a clearance hole, a pinning nozzle that corresponds to the depth of the hole should be used.
Pinning Nozzles
Thor Helical produces a range of pinning nozzles to suit different clearance hole depths.
Thor Helical Grout Gun Kit
The Thor Helical Grout Gun is used with interchangeable nozzles to install WHO-60 grout across different applications. A flattened nozzle applies grout to bed joints, while pinning nozzles — sized to match clearance hole depth — fill pinning holes. The kit includes the gun body, two barrels, a plunger rod assembly, and a selection of nozzles.
Downloads
Full technical data, test results and installation guidance
TH Masonry Pinning
Standard Ø9mm and Heavy Duty Ø12mm — tension/shear data, grout tie guidance.
TH WHO-60 Grout
Polymer-modified, cement-based, thixotropic mortar for use in Crack Stitching, Lintel repair and Masonry Pinning Grout Ties