Planning a Groundworks Package for a Commercial Development

Groundworks is the first physical work on any commercial development and the phase where the most money can be lost — or saved — before the superstructure even starts. Yet it is routinely treated as a commodity package, priced late, briefed poorly, and left to absorb the programme delays created by everyone upstream of it.

This article is for developers, principal contractors, commercial clients and project managers who are planning a groundworks package and want to do it properly. It covers what the package includes, how to brief and procure it, the information a contractor actually needs to price it accurately, and where early planning changes the commercial outcome.

No fluff. No manufactured case studies. Practical guidance you can use on a live project.

A commercial groundworks package covers every element of work below the underside of the structural frame — and on most projects, a fair amount above ground level before the superstructure contractor takes over the site.

On a typical commercial development, the package will include:

The package often extends into drainage tie-ins, service connections and reinstatement — anything that needs to happen below finished ground level before the above-ground structure can progress.

For how enabling sits inside that sequence, see Understanding Enabling Works. For commercial package delivery, see commercial groundworks contractors.

Ground risk is the single largest source of unplanned cost on a groundworks package. You cannot price what you have not investigated.

A proper site investigation programme should include:

• Desk study — geological maps, BGS records, historical maps, previous site reports, mining records where relevant
• Walkover survey — access constraints, adjacent structures, signs of contamination, watercourses, existing services
• Ground investigation — boreholes, trial pits, CBR testing, contamination testing, groundwater monitoring
• Factual and interpretive report — ground conditions, bearing capacities, groundwater levels, recommended foundation solutions

How many boreholes? There is no fixed rule, but for a commercial site of one to five hectares, a minimum of one borehole per 250–500 m² of built footprint is a reasonable starting point, supplemented by trial pits across the wider site to pick up localised variations. On contaminated or historically complex sites, increase density.

We regularly see tenders issued with incomplete GI — or with a factual report that never reaches the pricing team. One issue frequently encountered during commercial tendering is that the interpretive recommendations sit with the designer while the contractor prices from drawings alone. That gap is where foundation assumptions go wrong. For how ground conditions drive foundation strategy, see how ground conditions affect foundation design.

Temporary works are the unseen half of a groundworks package. They are rarely visible in the finished development but frequently determine whether the programme holds.

Typical temporary works on a commercial groundworks package include:

• Piling platforms — designed to support piling rigs; may require imported Type 1 or engineered fill
• Excavation support — sheet piling, trench boxes, H-pile and lagging systems for deep excavations
• Dewatering — wellpoint systems, sump pumping, or deep wells where groundwater sits above formation level
• Temporary propping — for basement formation, retaining walls and party-wall scenarios
• Temporary roads and hardstanding — for plant movement, delivery access, compound areas
• Temporary drainage — to manage surface water during construction before permanent systems are live

Temporary works must be designed, not improvised. A temporary works register should be established at the start of the package, with each item assigned a design responsibility, a category (Category 0–3 per BS 5975), and a checking route.

Decision guidance: who designs temporary works?

Excavation is where ground conditions meet the programme. The volume of material to be removed, the suitability of that material for reuse on site, and the cost of disposing of what cannot be reused are all variables that need to be understood before pricing.

Key considerations:

• Cut and fill balance — Can excavated material be reused for level raising, or does it all leave site? A cut-and-fill survey at design stage can save significant muck-away cost. See also earthworks services.
• Soil classification — Is the material inert, non-hazardous or hazardous? This determines disposal cost and whether it can be reused.
• Groundwater — If the water table sits above formation level, excavation will require dewatering and potentially a temporary support system. This is not a minor item.
• Access constraints — Can lorries get in and out of the site without affecting the surrounding highway? On constrained urban sites, muck-away logistics can govern the programme — which excavation contractors need to plan carefully.

Foundation selection is driven by ground conditions, structural loads and site constraints. The ground investigation report should recommend the appropriate solution, but the final decision should be a coordinated one involving the structural engineer, the groundworks contractor and the client.

Common foundation types on commercial projects:

The decision between a ground-bearing solution and a piled solution is not just technical — it is commercial. A piled solution may be more expensive per m² but can reduce excavation depth, programme duration and risk on poor ground. The trade-off should be assessed with whole-package cost in mind, not foundation cost in isolation.

Where access or ground conditions push the decision toward piles, Mini Piling vs Traditional Foundations sets out the practical method choices without treating piles as a default.

Drainage on a commercial development is not just about laying pipes. It involves adoption agreements, attenuation design, connection consents and sequencing against the wider programme.

A typical drainage scope includes:

• Foul drainage — connection to existing public sewer or private treatment system
• Surface water drainage — attenuation, infiltration or discharge to watercourse
• Sustainable urban drainage systems (SuDS) — permeable paving, swales, attenuation tanks
• Connection agreements — Section 104 (Water UK), Section 106 (foul connection)
• Existing sewer diversions — where existing services conflict with the development footprint

Drainage is frequently the element of a groundworks package that causes the most programme friction, because it depends on third-party approvals that sit outside the contractor's control. Section 104 agreements with the local water authority can take weeks or months to process. If the drainage design is not submitted for approval early, the package will stall.

A common source of delay on commercial programmes is treating adoption as a construction-stage activity. By then, layout changes and lead times are already competing with the dig. For adoption sequencing, see the drainage adoption process — the same approval logic applies on many commercial sites.

External works close out the groundworks package. They include everything from finished levels to access roads, footpaths, kerbing, hardstanding and service duct installation.

On many projects, external works are treated as a residual — whatever is left after the main structure is complete. This is a mistake. External works are the last chance to recover programme if earlier phases have slipped, but only if the scope, levels and service requirements have been defined in advance.

Typical external works scope:

• Formation and compaction of sub-base for roads and hardstanding
• Kerb installation and edging
• Footpath construction
• Service ducts and chambers installed ahead of final surfacing
• Final grading and reinstatement to finished levels
• Coordination with surfacing contractor on the interface between sub-base and wearing course

Utilities coordination is the element of a groundworks package most likely to be under-resourced. Existing services — gas, water, electricity, telecoms, fibre — may need to be diverted, protected or incorporated into the new development. New connections need to be requested, designed and installed, often by the utility provider's own approved contractor.

The problem is that utility providers operate on their own programmes. A new electricity connection can take 12–18 weeks from application to energisation. A gas main diversion may require a road closure permit that takes months to secure. If these activities are not identified and initiated at the start of the groundworks package, they will delay handover.

A groundworks programme should be sequenced around four things: access, ground conditions, weather and third-party dependencies.

1. Access — When can plant and delivery vehicles get on site? Is there a single access point? Are there weight or width restrictions? On constrained sites, access can dictate the sequencing of every operation.
2. Ground conditions — Seasonal groundwater levels, clay heave potential and soft ground in winter months all affect what can be done and when. Piling in high groundwater requires different methodology and cost.
3. Weather — Excavation, fill and concrete placement all have weather sensitivity. The programme should identify weather-critical operations and either protect them or sequence them into appropriate windows.
4. Third-party dependencies — Drainage approvals, utility connections, party-wall agreements, highway permits and environmental consents all sit outside the contractor's control. These should be on the critical path with lead times clearly marked.

A well-structured groundworks programme will:

• Identify the critical path through foundations and drainage
• Show temporary works design lead times as predecessors to installation
• Include third-party approval durations as fixed constraints
• Buffer weather-critical operations where possible
• Define the handover interface with the superstructure contractor — including levels, access and any temporary works to remain

Most groundworks cost problems are created at procurement, not at construction. The following are the most frequent mistakes:

To price a groundworks package accurately, a contractor needs the following:

The commercial case for early groundworks planning is straightforward:

• Ground risk is quantified, not assumed. A ground investigation that costs £15,000–£30,000 on a typical commercial site can prevent a six-figure variation claim when unforeseen ground conditions emerge during construction.
• Foundation solution is selected on data, not guesswork. The difference between a strip foundation and a piled solution can be tens of thousands of pounds per plot. The decision should be engineered, not defaulted.
• Temporary works are designed and costed, not improvised. A temporary works register established at planning stage prevents the reactive design, installation and disputes that occur when temporary works are managed on the fly.
• Third-party approvals are initiated early. Drainage connections, utility connections and highway agreements have lead times that do not compress. Starting them early is the only way to keep them off the critical path.
• Scope interfaces are defined. When the groundworks package has a clear start and end point, and every interface with adjacent packages is documented, variation claims reduce sharply.
• The programme is sequenced around real constraints. Access, ground conditions, weather and third-party dependencies are planned for, not discovered.

The pattern is consistent across commercial developments: projects that invest in early groundworks planning — investigation, design, scope definition and approval initiation — deliver on programme and within budget. Projects that defer these decisions to the construction phase pay for them in variations, delays and disputes.

A commercial groundworks package is only as strong as the information it is built on. Brief it early, investigate the ground properly, define responsibilities at every interface, and start third-party approvals before construction begins. That is how early planning, accurate information and clear ownership reduce commercial risk — and how the package protects programme instead of absorbing everyone else's delay.