2022
Salford, Manchester
Salboy Ltd
Domis Construction Ltd
Wright Landscapes
Green Terramesh Vegetated Retaining Walls at Castle Irwel
Challenge
Castle Irwell is a landmark 35-acre riverside residential development located on the historic former Manchester Racecourse site. The scheme will deliver 600 new homes and is designed with a strong focus on high-quality landscaping, sustainable drainage, and attractive public open spaces, including a public park, communal courtyards, and walking trails.
As part of the development, Domis Construction, working for developer Salboy, needed to deliver a series of structurally sound yet aesthetically pleasing retaining solutions within landscaped areas. Several public open spaces required vegetated retaining walls around watercourses and stormwater attenuation ponds. These structures needed to provide long-term stability while blending seamlessly into the natural environment.
In addition to visual requirements, the project presented technical challenges. The retaining structures had to accommodate stormwater management infrastructure, including pipework running through the walls, and perform effectively in a riverside environment. Wright Landscapes Ltd, responsible for the landscaping works, engaged Maccaferri to develop an efficient, durable, and environmentally sensitive retaining wall solution that could also be installed quickly to meet the construction programme.
Solution
Maccaferri proposed the Green Terramesh system, an engineered reinforced soil solution designed to create vegetated retaining walls with a natural green finish. This system was selected for its combination of structural performance, sustainability, and rapid installation capabilities, making it ideal for large-scale residential developments with tight deadlines.
The Green Terramesh solution featured a 70-degree front face, allowing vegetation to establish quickly and deliver an attractive, environmentally integrated appearance. Across the Castle Irwell site, six reinforced soil wall sections were constructed, covering a total length of approximately 400 metres.
A key advantage of the Green Terramesh system is its flexibility. Manufactured from double-twist steel wire mesh, the units can be cut and re-laced on site without compromising structural integrity. This enabled seamless installation of stormwater pipework through the retaining walls, ensuring full integration with the site’s sustainable drainage system.
Due to the proximity of the structures to watercourses and attenuation ponds, a 6I/6J granular backfill was used to provide effective drainage and maintain long-term performance. Where required, ParaGrid geogrids were incorporated to enhance soil reinforcement and ensure structural stability.
The Green Terramesh system offers a BBA HAPAS-certified design life of up to 120 years, providing a durable and cost-effective retaining wall solution. Each unit combines a steel mesh fascia with an integral erosion control mat, supporting vegetation growth and creating a green wall finish. The system also includes an integrated geogrid tail, which reinforces the compacted backfill, forming a stable reinforced soil structure.
To improve construction efficiency, the units feature a welded mesh panel and internal bracing struts that maintain the correct face angle during installation. This eliminates the need for temporary formwork or external supports, reducing labour and speeding up construction.
Overall, the use of Green Terramesh at Castle Irwell delivered a sustainable, visually appealing, and technically robust vegetated retaining wall solution, perfectly aligned with the project’s focus on high-quality landscaping and long-term environmental performance.
