Infrastructure & civils
Infrastructure-led projects demand formation control, adoptable highways and drainage coordination, and disciplined earthworks. We deliver civils groundworks that integrate with wider infrastructure programmes and authority inspection regimes.
Stakeholders include developers, civils consultants, highway authorities, water companies, principal contractors and funders monitoring adoption milestones. Delivery challenges include cut-and-fill balance, bond programmes, traffic management and synchronising off-site S278 with on-site S38 works.
Mainline delivers infrastructure groundworks to engineer specification — bulk movement, adoptable roads and sewers, attenuation and connection readiness — with clear sequencing and handover documentation.
Civils and infrastructure groundworks capability
Infrastructure and civils groundworks form the connective tissue of development sites — estate roads, adoptable sewers, attenuation, bulk earthworks and the off-site highway works that make a scheme accessible and adoptable. These packages must satisfy engineer design, authority inspection and the programme milestones that unlock plot sales and lender comfort.
Procurement routes reflect adoption complexity. Developers may let a single roads-and-sewers package, split earthworks from adoptable infrastructure, or procure S278 separately from estate civils. Framework contractors on public and private infrastructure programmes often price against standard details with authority-specific amendments.
Common requirements include formation compaction, adoptable carriageway construction, foul and surface water sewer laying, manhole and chamber construction, flow control and attenuation, testing and CCTV, and reinstatement planning. Cut-and-fill strategy directly affects haul routes, spoil balance and platform readiness for subsequent trades.
Regulatory considerations are extensive: S38 Highways Act agreements, S104 Water Industry Act adoption, S278 highway connections, environmental permits, traffic management approvals and CDM on live civils sites. Bond and surety programmes must align with technical approval — adoptable works cannot proceed to authority satisfaction without the correct agreements in place.
Mainline delivers infrastructure groundworks with discipline around engineer specification, inspection regimes and programme reporting. We support developers and principal contractors where civils packages must integrate with wider infrastructure programmes and adoption timelines.
Typical projects
Representative project types we deliver in this sector.
Highway schemes
Off-site carriageway works, junction improvements and S278 packages supporting site access.
Utilities infrastructure
Service corridors, diversion interfaces and deep drainage supporting development connectivity.
Adoptable roads
S38 estate roads with kerb, footway and carriageway construction to authority standards.
Section 278 works
Highway authority works connecting development access to the public network.
Services delivered
Groundworks and civils services relevant to infrastructure projects.
Roads and Sewers Contractors
Adoptable estate infrastructure — roads, foul sewers and surface water networks.
View service →Section 278 Contractors
Off-site highway connections, traffic management and authority-approved carriageway works.
View service →Section 38 Contractors
Estate road construction and technical approval packs for highway adoption.
View service →Section 104 Contractors
Adoptable foul and surface water sewers with testing and CCTV handover.
View service →Bulk Earthworks
Cut and fill, formation levels and platform compaction for civils programmes.
View service →Earthworks Contractors
Large-scale earthworks, haul management and formation control.
View service →Attenuation System Contractors
Storage crates, tanks and flow control integrated with adoptable drainage.
View service →Excavation Contractors
Trenching, deep excavation and service corridor preparation.
View service →Muck Away Services
Spoil removal and haul logistics on infrastructure-heavy sites.
View service →
How infrastructure civils are procured
Infrastructure packages are usually procured once drainage strategy, adoption route and technical approval status are defined. Bond programmes and authority correspondence are commercial gates as important as the bill of quantities.
Developer-led civils
Developer appoints roads-and-sewers contractor directly with adoption programme control.
Principal contractor subcontract
Civils package under main contract with integrated reporting and sequencing.
Split package tender
Earthworks, adoptable infrastructure and S278 let separately for risk allocation.
Framework delivery
Regional civils frameworks with pre-agreed inspection and mobilisation standards.
Competitive tender
Fixed-price tender against complete drawings, adoption status and GI information.
Why Mainline
How we reduce interface risk and deliver programme-led groundworks in this sector.
Drainage expertise
S104 adoption, attenuation and surface water packages delivered to authority standards.
Earthworks discipline
Cut-and-fill, haul and compaction managed against formation specifications.
Adoption programme alignment
S38, S104 and S278 sequenced around technical approval and bond milestones.
Inspection-ready delivery
Testing, CCTV and records structured for authority sign-off.
Civils programme experience
Infrastructure packages on developer-led and principal contractor programmes.
UK-wide capability
Civils delivery across London, the South East and regional infrastructure schemes.
Project delivery process
A structured approach from first enquiry through to handover.
- 1
Enquiry
Share your site location, programme, drawings and procurement route. We confirm scope fit and the information needed for a commercial return.
- 2
Scope review
We review formation levels, drainage strategy, adoption requirements, access constraints and interfaces with the wider design team.
- 3
Pricing & programme
You receive a priced package with sequencing assumptions, mobilisation plan and key commercial clarifications before award.
- 4
Site delivery
Groundworks are executed with QA checks, inspection coordination and programme reporting aligned to your site management processes.
- 5
Completion & handover
Testing, as-built records and formal handover are completed so the next trade or adoption milestone can proceed without delay.
Related case studies
Project examples from this sector will be published here.
| Project | Location | Value | Services delivered |
|---|---|---|---|
| Case studies coming soon | — | — | Groundworks packages will be published here as projects complete. |
Planning & technical guides
Resources to support procurement, design and commercial planning in this sector.
S278 agreements explained
Highway works connecting development access to the public network.
Adoptable roads explained
S38 adoption process for estate roads.
The S38/S104 programme explained
How adoption programmes are planned and managed.
Attenuation systems for developers
Surface water storage and flow control on civils schemes.
Drainage adoption (Section 104)
S104 sewer adoption requirements and sequencing.
Roads and sewers contractors guide
Procuring and managing adoptable infrastructure packages.
Infrastructure bonds and sureties
Bonds, sureties and commercial gates on adoption programmes.
Utility diversions for development sites
Statutory undertaker programmes and civils interfaces.
Excavation cost per cubic metre
Earthworks pricing and cost drivers.
Commercial drainage explained
Foul and surface water systems on infrastructure sites.
Infrastructure & civils — frequently asked questions
Common questions about groundworks delivery in this sector.
Do you deliver S38, S104 and S278 packages?
Yes. We deliver adoptable estate roads, sewer adoption packages and off-site highway works with authority inspection coordination.
Can earthworks and adoptable infrastructure be combined?
We price combined or split packages depending on procurement strategy, programme and risk allocation.
How do bonds affect civils mobilisation?
Adoptable works typically require agreements and sureties in place. We align mobilisation with technical approval and bond programme status.
What testing is included in sewer adoption?
Testing, CCTV and as-built records are coordinated to meet water company and authority adoption requirements.
When should infrastructure contractors be appointed?
Early appointment helps align cut-and-fill, adoption geometry and S278 prerequisites before fixed-price tender.
Need groundworks support for your infrastructure project?
Speak with our civils team about earthworks, roads and sewers, adoption packages and Section 278 works.