Understanding the 2025 MCHW Update
In September 2025, a major update was made to the Manual of Contract Documents for Highway Works (MCHW). While this update did not fundamentally change the materials used in highway construction, it has significantly altered how those materials are specified, referenced, and documented across projects.
For contractors, designers, and material users, the most noticeable change is the restructuring of the Specification for Highway Works (SHW). Long‑established series documents, including Series 500, 600, and 800, have been withdrawn and replaced with a new CC document structure. One of the most important of these is CC 201 – Pavement Foundation Construction, which now brings together requirements previously spread across several different series.
Although the performance requirements for familiar materials, such as Type 1 sub‑base and capping materials, remain broadly the same, clause numbers, document names, and references have changed. This can create uncertainty, particularly where older contract documents continue to apply, or where new schemes are being specified under the updated MCHW.
We recognise the importance of clarity when navigating specification changes, especially where compliance, sustainability, and material performance intersect. Understanding which version of the MCHW applies, and how new CC documents map across to older SHW references, is essential for avoiding confusion on site and at procurement stage.
To support this, the team at Day Aggregates have produced a clear, practical explainer that sets out what has changed, what has stayed the same, and what the update means in real terms for projects starting now. Read the Full Article.
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