Early market engagement begins for £15M A469 landslip repair scheme

Caerphilly County Borough Council has begun early market engagement with contractors ahead of a major scheme to stabilise a long-standing landslip affecting the A469 between New Tredegar and Pontlottyn.

The section of road at Troedrhiwfwch forms part of the council’s strategic highway network but has suffered repeated ground movement over several years. Since Storm Dennis in 2020, the carriageway has been restricted to single-file traffic controlled by temporary signals due to ongoing instability.

The authority describes the site as being located within a “very complex and significant” geotechnical setting, with difficult ground conditions contributing to the recurring landslip.

Two-year construction programme planned

Preliminary documents published by the council estimate the value of the works at around £15 million (including VAT), with construction expected to take place between November 2026 and November 2028.

Consultants Tetra Tech have already carried out the detailed design work and provided draft proposals for the remedial scheme.

The planned construction programme includes several major engineering interventions, including:

• Installation of 1,919 self-drilling soil nails

• Construction of 289 bored cast-in-place piles

• Replacement of gabion basket retaining structures

• Utility diversions for statutory undertakers

• Full carriageway reconstruction, including drainage, vehicle restraint systems and street lighting

Due to the challenging terrain and restricted access to the site, the works must be carried out in a strict sequence. Soil nailing will be completed first, followed by utilities diversion, gabion replacement and then the construction of a piled retaining wall.

Road closure expected during works

A Temporary Prohibition of Driving Order (TRRO) will be implemented to allow the A469 to be fully closed at the affected location while construction takes place.

The council notes that the site’s steep topography, limited working space and unstable ground conditions will make construction particularly complex.

Contractors invited to “Meet the Buyer” session

The scheme will be procured under an NEC4 contract, with the appointed contractor acting as principal contractor under the CDM 2015 regulations.

Caerphilly is seeking contractors with specialist experience in:

• Soil nailing

• Bored piling

• Road reconstruction in complex geotechnical conditions

Interested firms are invited to attend a “Meet the Buyer” workshop on 26 March, where the council will outline the project in more detail.

Follow-up one-to-one discussions will also be available to address key delivery issues, including:

• Site access and laydown areas

• Welfare and construction facilities

• Land negotiations and potential compulsory purchase orders (CPOs)

• Procurement and delivery arrangements

The formal tender is expected to be published on 16 April 2026, with full technical documentation – including geotechnical reports, cross-sections and design drawings – made available to registered contractors via a secure SharePoint link.

Key route for local communities

The A469 is an important route through the Upper Rhymney Valley, connecting communities and supporting travel to employment, services and local facilities.

While major stabilisation works will be necessary to resolve the long-term landslip issues, the council acknowledges that extended restrictions or full closures could significantly affect local journeys.

The early engagement exercise is intended to ensure the council secures the necessary specialist expertise and resolves land and access challenges before the formal procurement stage begins.