On phased residential developments, roads and sewers are the infrastructure that determines plot release dates. A plot cannot be released for sale and occupation until the road serving it is sealed and the sewers are adopted, or at the very least adopted-ready and signed off. The phasing of the civils programme therefore has direct commercial consequences for the developer’s sales cash flow.
The technical work of building roads and sewers is well understood. The harder problem on phased developments is the coordination of when each section of road is completed in relation to when each phase of plots is being released. Over-build the roads early and you commit infrastructure cost ahead of revenue. Under-build and you delay plot completions waiting for road sealing.
GCE’s experience on phased housing schemes is that the coordination is best done at the master programme level rather than left to emerge from the live site. The civils programme for roads and sewers is sequenced against the developer’s plot release programme. Each section of road is completed in time to support the plots it serves, with a contingency margin built in for adverse weather and material delivery.
The biggest scheduling risk is concrete and asphalt delivery during summer peak demand or winter weather restrictions. Asphalt cannot be laid when ambient temperatures fall below the manufacturer’s specification, which on UK winter sites can mean significant delays. Concrete delivery in summer can be constrained by supplier capacity. GCE’s procurement planning addresses both by establishing supplier commitments at programme stage rather than at material call-off.
Sewer adoption has its own programme dimension. Under the Sewers for Adoption (now Sewerage Sector Guidance) framework, the developer is delivering infrastructure that the water authority will eventually adopt. The pre-adoption inspections, hydraulic testing and final commissioning have specific durations that have to be programmed in. Section 104 agreements set out the technical standards.
Where a developer wants to release plots ahead of full sewer adoption, an undertaking or bond arrangement with the water authority can sometimes allow this. The detail varies by water authority and by region. GCE’s experience with the regional water authorities in the East and South East includes navigating these arrangements where the developer’s commercial position justifies it.
For developers managing portfolio cash flow across multiple phased schemes, the roads and sewers programme is one of the highest leverage items in the civils package. Bringing a road section forward by two weeks can unlock plot releases that affect the developer’s quarterly cash position. Slipping a section by two weeks can produce the opposite effect.
Highways adoption is the other piece of the roads coordination. Section 38 agreements with the local highway authority govern the adoption of the public road network within the development. The inspection regime is sequenced through the build, with specific checks at formation, sub-base, base course and surface course. Defects identified at any stage can require rework that affects the subsequent stages.
GCE coordinates the highway authority’s inspection programme with the developer’s plot release programme so that adoption progress supports rather than blocks plot completions. Where defects are identified, the remediation is planned and scheduled rather than absorbed reactively. The objective is to land the Section 38 adoption process at the moment the developer needs it for plot completions, not significantly earlier or later.
For QSs reviewing civils tenders on phased schemes, the question to ask is how the bidder coordinates roads and sewers against the plot release programme. A bidder that can articulate a documented approach has thought about the coordination. A bidder whose answer is generic has not, and the developer should expect to manage the coordination themselves on that scheme.
Talk to Globe Civil Engineering To discuss roads and sewers coordination across phased schemes on your scheme, contact Globe Civil Engineering on 01223 890727 or email enquiries@theglobegroup.co.uk.
