Treating historical structures with efficiency and care

When it comes to treating fragile heritage and historical structures, traditional methods such as underpinning and excavation are invasive, disruptive, and can cause irreparable damage, compromising the structural integrity and historical authenticity of the building.

Delicate historical materials require solutions that minimise the risk of harm by avoiding destructive interventions, ensuring the building’s original features remain intact. Since 1989, Mainmark has employed non-invasive techniques to treat buildings identified as heritage-listed or situated in World Heritage significant sites. Mainmark’s engineered resin solution, Teretek®, is particularly well-suited to address the causes of structural subsidence.

As a non-invasive technology, Teretek® resin injection does not require excavation. This means that when correcting subsided stone and brick footings, continuity of foundation support is maintained, and there’s no risk of damage to the footing that could occur with stones/bricks dropping into the excavation.

Teretek® can also be employed to improve the ground beneath existing footings prior to an extension being built, enhancing foundation support in preparation for construction works. Many historical buildings often stand on weak sub-grade soils that may have experienced settlement over time. By providing targeted ground improvement to these soils, Teretek® helps fortify the delicate foundations of historical structures, contributing to their long-term preservation and resilience.

Teretek® re-levels heritage café in Melbourne

Pioneer Park Café is located within one of the oldest buildings in the Melbourne suburb of Berwick, with parts of the existing structure dating back to 1876. The site was originally a primary school; however, the school closed in 2003, and the building commenced operating as a café and gift shop in 2006.

In 2018, due to challenges from highly reactive clay soil and the presence of heritage-listed elm trees with restricted root control measures, the café suffered from differential settlement. This caused structural damage, including a rotated end wall, stress cracks and separation at the openings on the two transverse walls.

As the property owner, the City of Casey engaged Mainmark to assess the 142-year-old site and recommend a remediation solution.

The project objective was to correct the rotated end wall and re-level the building, including the raised courtyard. Due to the heritage status of the building and elm trees, the City of Casey needed to feel confident that the solution would not impact the structural integrity of the building or damage the protected trees.

Mainmark employed its Teretek® resin injection solution, utilising its deep-lift application method. This process involves the injection of engineered structural resins beneath sunken sections of the affected structure, filling any voids encountered and compacting suitable or weak soils to maximise ground support. From deeper in the ground, the structure is lifted by the controlled force of the expanding resin.

Teretek® was applied through very precise injection points along the length of the building foundations to both the building and the courtyard retaining wall. This successfully raised the lowest corner of the building by 30mm. The courtyard retaining wall was also lifted 2 3mm, re-aligning it with the pavement slab.

Utilising Mainmark’s Teretek® solution enabled the works to be completed without the need for lengthy excavation works. This ensured minimal impact to the café’s operations while safeguarding the structural integrity of the building and the heritage-listed trees.

Read more about the project.