What Insurance Do Main Contractors Require from Groundworkers?

Introduction

If you’re a groundworker, you’ll know the job doesn’t start when the digger turns up — it starts when the paperwork is accepted. For most main contractors, insurance evidence is a non-negotiable part of onboarding. It protects the project, the client, and the supply chain, and it helps ensure that one incident doesn’t derail the programme.

This guide explains the types of insurance main contractors commonly require from groundworkers in the UK, what limits are typical, what documents you’ll be asked to provide, and how to avoid the common pitfalls that cause delays.

Why main contractors insist on insurance from groundworkers

Main contractors are responsible for delivering the project and managing risk across multiple subcontractors. Groundworks is a high-risk trade: excavation, underground services, plant, temporary works, and heavy vehicle movements all increase the chance of injury, property damage, and costly delays.

Insurance requirements are usually set out in:

• The subcontract order or subcontract agreement
• The main contract (e.g., JCT, NEC) flowing down the supply chain
• Site rules and pre-start questionnaires
• Client or funder requirements

In practice, the main contractor wants confidence that:

• You can pay for damage you cause
• Injuries to your staff are covered
• Your plant and hired-in equipment won’t become their problem
• Your policy wording matches the work you’re doing (and the contract you’ve signed)

The core insurances most main contractors require

1) Public Liability (PL) insurance

What it covers: Claims from third parties for injury or property damage arising from your business activities. For groundworkers, this can include damage to existing structures, footpaths, kerbs, boundary walls, or striking underground services.

Why it matters for groundworks: One cable strike can cause major losses: repairs, reinstatement, business interruption for neighbouring premises, and programme delays.

Typical limits requested:

• £2 million is common on smaller sites
• £5 million is a frequent baseline for commercial projects
• £10 million is common for larger projects, infrastructure, or where the client demands it

Common contract conditions to watch:

• Indemnity to principal: Extends cover to the main contractor/client where required.
• Contractual liability: Some contracts push extra liability onto you; your policy needs to respond.
• Heat work / work away exclusions: Less relevant to groundworks, but check any broad exclusions.
• Depth and underground services: Ensure the insurer knows you do excavation and groundworks.

Tip: Make sure your business description is accurate. “General builder” can be too vague. If you do drainage, RC works, underpinning, or deep excavations, say so.

2) Employers’ Liability (EL) insurance

What it covers: Your legal liability if an employee is injured or becomes ill due to their work.

Is it required by law? In most cases, yes. UK businesses with employees usually must have EL with a minimum limit of £5 million, though most policies provide £10 million as standard.

Why main contractors ask for it: Groundworks involves manual handling, plant movements, confined spaces, and exposure to dust, vibration, and noise. Main contractors want assurance that injuries to your workforce won’t become a dispute that delays the job.

Typical limits requested:

• £10 million (standard)

Documents you’ll be asked for:

• EL certificate (often displayed on site or provided digitally)

Tip: If you use labour-only subcontractors, agency staff, or CIS operatives, clarify who is responsible for EL. Main contractors will often ask how you engage labour.

3) Contractors’ All Risks (CAR) / Contract Works insurance

What it covers: Damage to the works while they’re being carried out (materials, part-completed works). It can also include tools, plant, and sometimes hired-in plant, depending on the policy.

Do groundworkers always need it? Not always — sometimes the main contractor’s project policy covers the works. But many main contractors still require subcontractors to carry their own Contract Works cover, especially if:

• You’re responsible for a defined package
• You store materials off-site
• You’re doing enabling works before the main policy is in place

Typical limits requested:

• Based on your contract value (e.g., £250k, £500k, £1m+)

Key wording points:

• What is defined as “the works” under your policy
• Off-site storage and transit (materials in a yard, on a vehicle, or at a lock-up)
• Existing structures (if you’re working adjacent to or within existing buildings)

Tip: If you’re doing work on or near existing structures, ask whether the main contractor expects you to cover “existing property” or whether it’s under their policy.

4) Plant and machinery insurance

What it covers: Damage to your owned plant (excavators, dumpers, rollers) and sometimes hired-in plant. It can also cover theft, vandalism, and accidental damage.

Why main contractors care: Plant is central to groundworks. If your machine is stolen or damaged, the programme can slip. Also, if you damage hired-in plant, the hire company will pursue the hirer (often you).

Typical requirements:

• Cover for owned plant to replacement value
• Hired-in plant cover if you hire equipment

Extras that are often expected:

• Theft from site (with security conditions)
• Immobiliser / tracker requirements for higher-value plant
• Hired-in plant “responsibility” wording

Tip: Check the security conditions. If your policy requires specific fencing, lighting, or immobilisers and you don’t comply, theft claims can be declined.

5) Hired-in plant insurance

What it covers: Your liability for loss or damage to plant you hire.

Why it’s often requested: Many groundworkers hire specialist attachments, breakers, trench boxes, or additional machines for peak periods. Hire agreements typically make you responsible from delivery to collection.

Typical limits requested:

• A set hired-in plant limit (e.g., £25k, £50k, £100k+), depending on the scale of hire

Tip: If you hire frequently, set a realistic limit. A low hired-in plant limit can cause last-minute issues when you need to hire a bigger machine.

6) Professional Indemnity (PI) insurance (sometimes)

What it covers: Claims arising from professional advice, design, specification, or errors in surveys and setting out.

Do groundworkers need PI? Many don’t — but it becomes relevant if you:

• Take on any design responsibility
• Provide setting-out services
• Advise on ground conditions, drainage design, or temporary works
• Work under a “design and build” arrangement or accept design liability in the subcontract

Typical limits requested:

• £250k to £1m is common for smaller packages
• £1m to £5m for higher-risk or design-heavy work

Tip: If the contract includes “fitness for purpose” obligations, get advice. PI policies are usually written on a “negligence” basis and may not respond to strict fitness-for-purpose obligations.

Other covers that may be required (or strongly recommended)

7) Public Liability extensions: underground services and vibration

Groundworks often involves:

• Excavation near services
• Vibration from compaction
• Work adjacent to existing buildings

Some insurers apply exclusions or special conditions for:

• Damage to underground services
• Vibration, weakening or removal of support

Tip: If a contractor asks for confirmation that your PL covers “vibration and weakening of support,” don’t guess — ask your broker to confirm the wording.

8) Pollution / environmental liability (where relevant)

If your work could cause pollution (fuel spills, contaminated soil, silt run-off into drains or watercourses), the main contractor may ask about pollution cover.

Many PL policies include limited “sudden and accidental” pollution cover, but it may be restricted.

Tip: If you’re working near watercourses or doing remediation, discuss environmental liability specifically.

9) Motor insurance (business use) and fleet

If you have vans, tippers, or HGVs moving to and from site, the main contractor may want reassurance you have appropriate motor cover.

This is especially relevant if:

• You’re delivering materials
• You operate tippers on or between sites
• You have drivers under 25 or new drivers

10) Tools insurance

Not always required by the main contractor, but worth considering. Theft of tools can stop a job and create replacement costs.

11) Personal Accident cover

Not usually a contractor requirement, but useful for sole traders and directors. It can provide a weekly benefit if you’re injured and unable to work.

Typical insurance limits main contractors ask for (quick guide)

Limits vary by project, location, and client requirements, but a common set of expectations looks like this:

• Public Liability: £5m (often £10m on larger sites)
• Employers’ Liability: £10m
• Contract Works/CAR: to contract value
• Plant: to replacement value
• Hired-in plant: to realistic peak hire exposure
• Professional Indemnity (if design/advice): £250k–£5m depending on scope

If you’re tendering for multiple contractors, it can be worth aligning your limits with the most common requirement you see — otherwise you’ll be adjusting cover mid-year.

What documents main contractors typically ask you to provide

Expect to be asked for:

• Certificate of Public Liability
• Certificate of Employers’ Liability
• Schedule and wording (sometimes)
• Evidence of policy limits and excesses
• Confirmation of key extensions (e.g., indemnity to principal)
• Policy period dates (must cover your work dates)

Some main contractors also request:

• A letter of confirmation from your broker
• A copy of your risk assessments and method statements (RAMS)
• Plant inspection records (e.g., LOLER where applicable)

Common reasons groundworkers get delayed at onboarding

Your trade description doesn’t match the work

If your policy says “landscaping” but you’re doing drainage and excavation, the contractor may reject it.

The limit is too low

A £2m PL policy may be fine for some domestic work, but many commercial sites will require £5m or £10m.

No hired-in plant cover

If you need to hire a machine next week and your policy doesn’t include hired-in plant, the hire company may insist on cover before delivery.

Exclusions you didn’t know you had

Common problem areas include:

• Work below a certain depth
• Work near railways or water
• Vibration/weakening of support
• Use of certain plant types

Policy dates don’t cover the programme

If your policy renews mid-project and you can’t confirm renewal terms, some contractors will pause onboarding.

How to respond when a main contractor sends an insurance schedule

When you receive an insurance requirements schedule, don’t just check the limits. Work through it like a checklist:

1. Confirm the scope matches your subcontract package (excavation depth, drainage, concrete, kerbs, services).
2. Check limits (PL/EL/PI) and whether they require any one occurrence or in the aggregate.
3. Confirm extensions (indemnity to principal, contractual liability, cross liability).
4. Check excesses and whether the contractor has maximum excess requirements.
5. Confirm territorial limits (UK is standard, but check if any offshore work is involved).
6. Ask for clarification on project insurance: is there a main project CAR policy that covers the works?

If anything doesn’t match, it’s usually quicker to resolve before you mobilise.

Groundworks-specific risk areas contractors worry about

Main contractors often focus on a few recurring risk themes:

• Striking underground services (gas, electric, fibre)
• Collapse of excavations and injury
• Damage to neighbouring property from vibration or removal of support
• Plant incidents (reversing, lifting, attachments)
• Flooding from damaged drainage or temporary works failures
• Contaminated ground and disposal issues

Your insurance is only one part of the picture, but having the right cover in place makes you easier to onboard and more attractive to work with.

FAQs

Do I need £10m Public Liability to work for a main contractor?

Not always, but it’s common on larger commercial projects. Many contractors set £5m as a baseline and increase it based on client requirements.

If the main contractor has project insurance, do I still need my own cover?

Often yes. Project insurance may cover the works, but it usually doesn’t replace your responsibility for third-party injury or damage, and contractors still want your PL and EL in place.

I’m a labour-only groundworker. Do I still need insurance?

It depends on your contract and how you’re engaged. If you’re genuinely labour-only under the contractor’s control and using their plant, the contractor may cover more of the risk. But many “labour-only” arrangements still require PL (and sometimes EL if you have employees).

Does Public Liability cover damage to the works I’m building?

Not usually. PL is for third-party injury or damage. Damage to the works is typically under Contract Works/CAR.

What if I do setting out or give advice on drainage?

That can create a PI exposure. If you’re taking on design or advisory responsibility, ask whether PI is required and ensure your policy matches the contract.

Call to action

If you’re a groundworker tendering for main contractor work, getting your insurance right can save days of back-and-forth and help you win more packages.

If you want, tell us:

• The type of groundworks you do (drainage, foundations, kerbs, RC, deep excavations)
• Whether you hire plant
• Typical contract values and who you work for

…and we can help you line up the right cover and limits for the projects you’re targeting.