GRS buys back Tarmac stake: materials supply and rail logistics notes for engineers
Reviewed by Joe Ashwell

First reported on The Construction Index
30 Second Briefing
Construction materials distributor GRS Roadstone Group has regained full ownership by buying back Tarmac’s 23.7% stake for an undisclosed sum, following a decade in which GRS expanded ten-fold and reached £480m revenue with £3.0m pre-tax profit to 31 January 2025. The company will retain aggregate supply agreements with Tarmac and continue promoting inert waste disposal in Hertfordshire, signalling continuity for key materials flows. GRS Rail Services remains a 50:50 joint venture, operating railheads at Birmingham, Luton, Northampton, Peterborough and Wellingborough that feed HS2 aggregate supply.
Technical Brief
- Tarmac’s divested holding was a 23.7% minority equity stake in GRS Roadstone Group.
- GRS originated from a 1997 management buy-out of Galliford’s roadstone operations, pre-dating the Galliford Try merger.
- Tarmac’s shareholding traces back to Lafarge UK joint ventures prior to the Lafarge–Tarmac 2013 merger.
- Revenue to 31 January 2025 reached £480m, but pre-tax profit fell to £3.0m from £9.2m year-on-year.
- GRS now operates across bulk aggregates, waste and recycling, building products, contracting, freight, logistics and associated services.
- GRS Rail Services continues as a 50:50 JV, running railheads at Birmingham, Luton, Northampton, Peterborough and Wellingborough.
Our Take
With revenues of £480m but pre-tax profit slipping from £9.2m to £3m in the year to 31 January 2025, GRS’s buyback of Tarmac’s 23.7% stake likely reflects a push to capture more margin in a low-margin UK aggregates logistics market rather than simple scale growth.
Control over GRS Rail Services’ 50:50 rail JV and the railheads in Birmingham positions GRS to compete more directly with vertically integrated majors in our UK Infrastructure coverage, where only a handful of aggregates-focused pieces highlight comparable in-house rail capability.
Given GRS’s tenfold growth since 1997 and its footprint across Hertfordshire, Luton, Northampton, Peterborough and Wellingborough, full ownership may make it easier to standardise pricing and supply strategies into HS2-related and other major civils workstreams that dominate recent Infrastructure project stories in our database.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
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