Mace accelerates Paddington over-station development: delivery and design notes for engineers
Reviewed by Joe Ashwell

First reported on The Construction Index
30 Second Briefing
Mace will start main works in early 2025 on Helical’s £200m, 235,000 sq ft over-station office scheme above Paddington station, a 19-storey Grimshaw-designed canalside building with 15 office floors and ground-floor retail, now targeting completion in Q3 2028 instead of Q4 2028. Preparatory works are already under way ahead of formal site acquisition in January 2026, with Helical developing the project in joint venture with Places for London. Helical has also agreed heads of terms for forward funding a 429-studio student block above Southwark Tube and forward sale of 44 affordable homes to Southwark Council, with construction planned from H1 2026 to 2029.
Technical Brief
- Early contractor engagement with Mace has shortened the programme sufficiently to move completion forward one quarter.
- Contract value for Mace’s main works package is reported at £200m, indicating a high-spec superstructure and fit-out.
- The Grimshaw-designed scheme delivers 235,000 sq ft net office area above an operational mainline and Underground hub.
- Over-station construction above Paddington will require staged works around live rail operations and constrained canalside access.
- Formal site acquisition is not due until January 2026, so enabling works proceed under separate early agreements.
- Helical is delivering both over-station schemes in joint venture with Places for London, consolidating TfL air-rights development.
- At Southwark, heads of terms cover forward funding of 429 student studios plus forward sale of 44 affordable units.
- Both Southwark buildings are programmed to start on site in H1 2026, with practical completion targeted in 2029.
Our Take
Within the 57 Infrastructure stories in our database, very few schemes combine an over-station commercial build like Paddington with a separate student and affordable housing component above another Tube station, signalling Transport for London’s Places for London arm is testing more complex, multi-node value capture models on its estate.
A £200m contract to Mace for a 19-storey canalside and 15 floors of offices places this firmly at the upper end of London station air-rights projects in our coverage, which typically sit below this scale, suggesting Helical and TfL are targeting a prime office-led asset rather than a predominantly residential mix.
The forward sale of 44 affordable homes above Southwark Tube station to the London Borough of Southwark gives the scheme an early revenue de-risking element, a pattern seen in only a handful of our recent London infrastructure pieces and one that can help secure financing and political support through to the Q3 2028 horizon.
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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