De Uitdaging

Extensive Moving Brickwork and Structural Cracking

With over three decades in the industry we often see the consequences of long-term ground movement. This recent project in Wiltshire presented a significant but familiar challenge: a two-storey bay window repair necessitated by severe verzakkingsproblemen repair issues affecting both the front and rear elevations of the property. The overall impact was widespread, resulting in highly visible and structurally compromising moving brickwork.

Our initial survey revealed the complexity and depth of the damage, indicating that the building fabric was under significant rotational and sheer stress:

1. Severe Wall Cracking

The most immediate concern was a large, active crack located above the rear bedroom window. An internal inspection confirmed the severity: the wall above the lintel was heavily fractured, exhibiting differential movement of up to 20mm horizontally en 12mm vertically. This type of damage signifies classic rotational verzakkingsproblemen – where one part of the foundation drops – and creates extreme tension and compression forces within the upper masonry. Crucially, the crack narrowed as it approached the window, confirming that the structural stress was concentrated at the top of the opening.

2. Historic Ground Instability

While the primary cracks were active, we also noted several signs of historic masonry movement. External examination of the brickwork showed minor cracking originating from the lintel ends. However, the critical evidence was found in the wide, uneven perpend joints that had been heavily repointed. This indicates that the movement has been occurring over a long period, requiring previous, temporary attempts at wall cracking repair. This historic context was reinforced by the fact that the adjacent property showed identical cracking patterns and prior repointing, suggesting a common, deep-seated ground instability issue.

3. Compromised Bay Window Integrity

The front elevation’s two-storey bay window was clearly failing. The left brick pillar displayed a prominent crack and had begun to bow both outwards and sideways. The accompanying window sill crack extended down the masonry below, suggesting the column was losing its vertical load-bearing capacity and lateral restraint. Furthermore, we identified a possible contributing factor in the nearby rainwater downpipe, which discharged directly into the front flower bed. Water ingress close to the footing can saturate the subsoil, weakening its bearing capacity and exacerbating the verzakkingsproblemen that leads to moving brickwork.

This comprehensive assessment determined that a simple crack filler or surface repair would be inadequate. A dual approach combining foundational stabilisation with dedicated metselwerkwapening was the only way to achieve a long-term, successful verzakkingsproblemen repair.

De Oplossing

Integrated Foundation and Masonry Reinforcement

Our proposed solution was a targeted, two-phase structural intervention designed to permanently halt the ground movement and restore the monolithic strength of the masonry structure.

1. Foundation Stabilisation via Underpinning (Heli Pile)

To address the verzakkingsproblemen repair at its source, we specified the installation of our robust Helipalen around the affected perimeter of the bay window. This technique transfers the building’s load from the unstable shallow soil down to competent, deeper strata. This is the only way to ensure the moving brickwork stops permanently.

2. Advanced Masonry Reinforcement

To integrate the fractured masonry into a cohesive unit and redistribute loads away from the damaged areas, we chose our versatile Bar Flex system. This system would be used for three critical functions:

• Scheurnaden: To tie the split brickwork on the bay pillar and the internal gable end.
• Beaming: To create new lintel-like support zones beneath the first-floor bay window opening, spanning the zone of previous movement.
• Foundation Bonding: To mechanically link the newly stabilised foundation (the Helipalen) directly into the existing moving brickwork, creating a solid cap and preventing any further vertical settlement.

Bar Flex was chosen specifically because its flexibility allows for a smooth transition under tension, developing greater strength than traditional mild steel reinforcement while remaining completely hidden within the mortar joints, preserving the aesthetic integrity required for bay window repair.

Installatie

The installation phase was executed meticulously by our licensed installers Target Structural Wessex to guarantee the longevity and performance of both the verzakkingsproblemen repair and the wall cracking repair.

1. High-Performance Heli Pile Installatie

We installed 100mm diameter Helipalen in four strategic positions around the bay window. Each pile was driven to a substantial depth of four metres to guarantee penetration into stable ground. The driving process for all 16 metres of piling was completed in a total combined time of just over three hours, demonstrating the efficiency of the Heli Pile system compared to mass-concrete underpinning.

Following installation, each position was load tested to confirm its capacity. While the design requirement was set at a minimum of 60 kN, every single position comfortably tested over 70 kN. This provided absolute certainty that the foundation was stable and capable of bearing the structure’s load without future settlement.

2. Bar Flex Installation and Bonding

- Masonry Reinforcement process involved the careful installation of the Bar Flex system:

• Slot Preparation: Horizontal mortar joints were cut to the required depth and length along the lines of the cracks and beneath the first-floor opening. Each slot was rigorously cleaned using a vacuum and thoroughly flushed with water to ensure optimal adhesion.
• Bond Flex en Bar Flex Placement: Using the Bond Flex gun kit, a 10mm deep bead of the high-strength Bond Flex was injected into the back of the slot. The pre-measured 6mm Bar Flex rods were then pushed firmly into the Bond Flex to achieve full coverage. A further bead of Bond Flex was applied over the exposed bar.
• Finishing: The slots were finished by hand using a finger trowel to iron the mortar into the joint, resulting in an invisible wall cracking repair that leaves the structure looking untouched but now significantly strengthened.

3. Permanent Structure-to-Foundation Link

The final, critical step in the verzakkingsproblemen repair was linking the house foundations to the new Helipalen. This involved:

• Using 8mm Bar Flex, we created U-shaped links that wrapped around the installed Heli Piles in three critical positions.
• This reinforcement was grouted with Bond Flex into the existing brickwork and extended down to the foundation level.
• A concrete cap was then poured around the top of the Helipalen, setting the Bar Flex and completing the bond. This action ensures a solid, continuous link between the building and the deep-seated Helipalen, completely eliminating the risk of further moving brickwork and securing the bay window repair.

To conclude the project, we performed final scheurnaden on the interior gable wall where heavy step cracking was evident, consolidating the internal leaf and confirming that the entire structure was now stable. The property is now structurally sound, protected from further damage, and ready for redecoration.

Problems with Subsidence and Wall Cracking? Neem contact met ons op today!