Enabling Works Before Construction: What Should Be Completed Before the Main Groundworks Package Starts?

Enabling works are the activities that prepare a site for the main construction phase. They are often the first operations on site and typically include site clearance, demolition, utility disconnections, temporary access and working platforms, and the installation of site welfare.

For procurement professionals, the distinction between enabling works and the main groundworks package is not always clear-cut. The scope split varies between projects, and that ambiguity creates commercial risk. This article sets out what enabling works typically involve, what should be completed before the groundworks contractor takes over, and what procurement teams should be looking for when scoping and procuring this phase.

For a broader package view, see Planning a Groundworks Package for a Commercial Development. For definitions and scope language, see What are enabling works?.

The distinction is not always well-defined in contracts. In practice, enabling works are the activities that make the site accessible, safe, and ready for the main construction works to begin. Groundworks, by contrast, are the activities that form the permanent substructure—foundations, drainage, sub-bases, and external works.

The practical difference is that enabling works are temporary and preparatory, while groundworks form part of the permanent works. A haul road is an enabling work. The concrete foundations are groundworks.

However, some activities span both. Reduced-level excavation—digging the site down to formation level—might be scoped as enabling works on one project and as part of the groundworks package on another. Bulk earthworks on a housing scheme of 200+ plots might be split between a specialist earthworks contractor (enabling) and a groundworks contractor (foundations and drainage).

Scope gap risk:

• If enabling works and groundworks are procured separately, there must be a clear interface definition.
• Who owns the formation levels?
• What condition is the site left in?
• What happens if the enabling works overrun and the groundworks team is on standby?

Before any physical work starts, the site conditions must be understood. Enabling works should not begin until the site investigation is complete and the findings have been reviewed.

Ecology and tree protection. Disturbing protected species is a criminal offence, with potential fines of up to £5,000 per offence and/or up to six months imprisonment. Where tree protection is required, Root Protection Areas and protective fencing should be installed before any machinery arrives on site.

Enabling works should not commence until the necessary planning conditions have been discharged.

Planning conditions that affect enabling works:

• Construction Environmental Management Plan (CEMP) approval
• Tree protection requirements (BS 5837:2012 compliance)
• Hours of operation restrictions
• Contaminated land remediation requirements
• Archaeology watching briefs

• Regulatory approvals may include Section 61 (Control of Pollution) consent, Environment Agency permits for dewatering or remediation, water company approval for works near public sewers, and demolition licences where required.
• CDM 2015 compliance applies from the start of enabling works. A Construction Phase Plan is a legal requirement before any construction work begins and should be in place for the enabling phase.

Site clearance and demolition are often the first visible activities on site — typically delivered by site clearance contractors as part of a wider enabling works package.

Vegetation clearance removes trees, scrub, and vegetation from the working areas. Where trees are protected, this work must be carried out in accordance with the agreed arboricultural method statement, and Root Protection Areas must be fenced off before any machinery enters the site.

Demolition and soft strip — define the scope:

• What is to be demolished (full demolition or partial?)
• How materials are to be processed (crushed and reused, or removed?)
• Waste classification and disposal routes
• Asbestos survey and removal requirements

Waste management is a significant cost driver during enabling works. Material that can be crushed and reused on site reduces muck-away costs and imported fill requirements. Contaminated material requires specific disposal routes and carries a premium — often one of the drivers in a broader groundworks cost breakdown.

Before the groundworks package begins, the site needs to be disconnected from existing services or have services diverted to their new positions.

• Service disconnections should be coordinated with the relevant utility providers (UKPN, Cadent, water authorities). This process has lead times that must be factored into the programme.
• Temporary services may need to be installed for site welfare, lighting, and plant. The enabling scope often includes ducting, pipework, and drainage to and from welfare facilities, along with small concrete bases for cabins.
• Service diversions can be significant items of cost and programme. If a gas main or water pipe runs through the proposed building footprint, it must be diverted before foundation work can start. The lead time for utility diversion work is often underestimated.

Identify diversion and disconnection lead times before the digger is booked — not after the groundworks contractor is on standby.

The site must be made accessible for the plant and labour that will deliver the main works. This is core site preparation work and should not be left as an afterthought for the groundworks contractor.

Site access typically includes:

• Vehicular access from the public highway (may require highway permits or temporary traffic management)
• Haul roads across the site (typically 300mm of 6F2 with geogrid reinforcement, depending on ground conditions)
• Turning areas for delivery vehicles
• Working platforms for plant and concrete pumps

• Working platforms and hardstanding are required for plant and cranes (pile mats or crane platforms), site accommodation, material storage, and concrete pump positioning.
• Design is often driven by ground conditions. Weak ground may need more substantial reinforcement—geogrid and granular fill—to support concrete lorries and piling rigs.
• Wheel wash facilities are often required on sites with mud on the public highway and should be installed at the site exit before earthmoving begins.

Securing the site is typically the first physical activity in enabling works.

• Hoarding and fencing establishes the site boundary and provides security and public protection. Timber hoarding (including painting), Heras fencing, and vehicular gates are standard installations.
• Site signage is required for project identification, safety warnings, and access information.
• For a standard residential development, perimeter security and initial welfare setup can typically be achieved within 3–5 days.

Welfare facilities must be in place before any work starts. The CDM 2015 requirements are clear: adequate toilets, washing facilities, drinking water, and rest areas must be provided for site personnel.

Bulk earthworks are where the boundary between enabling works and groundworks is often blurred. On larger schemes, bulk earthworks may sit with a specialist contractor before foundations and drainage start.

• Reduced-level excavation (digging the site down to formation level) is often scoped as enabling works. The material removed is either exported or reused on site.
• Cut and fill calculations are based on the topographical survey and the design levels. If the survey is accurate, the cut-and-fill balance can be optimised to reduce muck-away and imported fill.
• Subgrade preparation involves trimming and compacting the formation to the required levels and specification. Weak spots may need to be excavated and replaced with suitable material.

Variations in ground levels found during excavation are a common source of cost increase — particularly where the topographical survey was incomplete or outdated.

Environmental mitigation is often required during enabling works and must be in place before the main groundworks start.

• Erosion control measures such as silt fencing and temporary drainage need to be installed before any earthworks that could generate run-off.
• Dust suppression may be required, particularly on sites near residential areas.
• Waste management requires designated skips or waste areas and compliant waste transfer notes.

The relationship between enabling works and the groundworks package is a programme-critical interface.

Sequencing considerations:

• The enabling works programme should establish the site datum and formation levels so that the groundworks contractor can set out and start without rework.
• If utilities are being diverted, the enabling works contractor should complete this before the groundworks contractor starts excavating for foundations.
• The enabling works contractor should install working platforms and haul roads to the standard required for the plant that will deliver the groundworks package.

Commercial considerations:

• If enabling works and groundworks are procured separately, the handover point must be clearly defined — site condition, residual works, and information passed across.
• If a single contractor is appointed for both packages, the interface risk is removed, and the programme can be managed more flexibly. Early finish on enabling works can bring groundworks forward; design issues found during enabling can be addressed without a variation passing between two organisations.

When procuring enabling works, treat information completeness with the same discipline as the main package. See What Information Should You Have Before Requesting a Groundworks Quote? and tendering groundworks packages.

Enabling works are where construction projects are won or lost on programme. The work is often unseen, but the consequences of incomplete scope or poor sequencing are visible throughout the remainder of the project.

For procurement professionals, the key is clear scope definition, adequate site investigation before pricing, and a realistic allowance for lead times on utility and regulatory approvals. A robust enabling phase reduces uncertainty for the groundworks package that follows.

If you are planning a project and need to understand the interface between enabling works and the main groundworks package, Mainline Groundworks can review the available information and discuss how the scope should be structured to minimise programme risk. Contact the team to talk through drawings, surveys and programme constraints.