The insurance a UK site will ask to see, and the one the law makes you buy

A main contractor emails you a pre-qualification pack on a Tuesday and wants certificates by Friday: £5m public liability, £10m employers' liability, contract works, and a schedule of your tools cover. You have a £62 policy from a comparison site with £1m on it and no employees, and you cannot tell from the certificate whether that is a problem or a formality.

It is both. One of those covers is compulsory under an Act of Parliament and carries a fine for every single day you trade without it. The rest are compulsory because a contract says so, which in practice is just as binding and considerably easier to negotiate.

This page walks the covers in the order a contractor actually meets them, names the statute or the contract clause behind each one, and prices the ones that can be priced.

Every cover, and which ones are law

Only one line in this list is a statute. That single fact reorganises the whole subject, because it tells you which arguments are worth having with a client and which are not.

Two of those are enforced by someone with a warrant card. The other seven are enforced by the person who is about to give you work, which means they are negotiable up to the point where they are not, and knowing which is which is most of the skill.

Public Liability: the number is written in your contract, not on a comparison site

Public liability covers what you do to other people and their property. A scaffold board through a conservatory roof, a customer's mother tripping on your extension lead, a burst pipe you disturbed that comes through a downstairs ceiling. It does not cover injury to your own workers, which is a separate cover with its own Act, and it does not cover the thing you were building.

Nothing in UK law obliges a builder to carry it. What obliges you is the contract, the site rules, or the scheme you joined. That distinction matters because it tells you where to look for the required figure: not on a broker's landing page, but in the paperwork in front of you. Under a JCT contract the sum is typed into the Contract Particulars, and the contract simply requires you to insure for not less than that amount. A council tender states it in the instructions to tenderers. A commercial lease states it in the tenant's covenants. A main contractor states it in their subcontract conditions and then asks for the certificate to prove it.

Who asks for which band

The bands are not arbitrary. They track the size of the third party who might sue you.

A rail possession job where you shut a line for a night is a different financial animal from a bathroom in a semi. Ten million pounds sounds absurd until you price six hours of delay attribution across a train operating company's fleet.

Any one occurrence, and the word that changes what you own

Read how the limit is expressed, because two policies both saying "£5,000,000" can mean very different things.

Any one occurrence means the full limit is available for each separate incident, however many times you claim in the year. This is what construction contracts almost invariably require and what a main contractor's insurance schedule reviewer is looking for.

In the aggregate means the limit is the total available for the whole policy year. Two claims of £3m leave you £1m short on the second one, out of your own money.

Public liability is usually written any one occurrence. Products liability, professional indemnity and pollution extensions are frequently written in the aggregate. If a certificate says £5m and the contract says £5m any one occurrence, the certificate has not yet answered the question.

Products liability, which is not optional for an installer

Products liability covers harm caused by goods you supplied after they have left your control. Fit a boiler, a balustrade, a wood burner or a bank of solar panels and you have supplied a product. It is normally written into a trade combined policy at the same limit as the PL, and it is normally written in the aggregate. When a main contractor asks for "£5m public and products liability", they are asking about two limits, and the second one is the one worth checking.

What a public liability policy costs in 2026

Real published prices for 2026, from insurers who print them:

Those figures come from Tradesman Saver and Rhino Trade Insurance, both of whom publish live quote examples. Tradesman Saver states that 30% of new customers paid £55 between 1 February 2026 and 31 July 2026. Simply Business reports that 85% of its customers buy £1m and 15% buy £2m.

The rating logic underneath is more useful than any single number. Trade drives the premium far harder than the limit does. Rhino puts it plainly: lower-risk trades such as cleaning or carpentry pay less than gas, plumbing or groundworks. Height, heat and excavation are what price a policy, because they are what produce the losses. Add employees and the premium changes shape entirely, because employers' liability arrives with them.

The practical consequence: stepping from £1m to £5m usually costs a great deal less than a contractor expects, and a lot less than losing the tender that required it. Get the quote both ways before you decide the £5m requirement is unreasonable.

Employers' Liability: the £5m the law makes you buy

This is the one with an Act behind it. Section 1(1) of the Employers' Liability (Compulsory Insurance) Act 1969:

Except as otherwise provided by this Act, every employer carrying on any business in Great Britain shall insure, and maintain insurance, under one or more approved policies with an authorised insurer or insurers against liability for bodily injury or disease sustained by his employees, and arising out of and in the course of their employment in Great Britain in that business, but except in so far as regulations otherwise provide not including injury or disease suffered or contracted outside Great Britain.

The amount is set by regulation 3 of the Employers' Liability (Compulsory Insurance) Regulations 1998, SI 1998/2573: not less than £5 million in respect of a claim relating to any one or more employees arising out of any one occurrence, and any costs and expenses incurred in relation to any such claim. HSE's guide for employers, HSE40, adds the detail that decides whether £5m is really £5m: the minimum includes costs, so a £4.6m award with £500,000 of legal costs has already gone through it. In practice most insurers write £10m as standard, which is why the certificate on your wall usually says ten.

What it costs you to not have it

The words "for any day" in section 5 are the whole point. This is not a single fine for a single offence. An HSE inspector who finds you three months into an uninsured stretch is looking at a per-day figure, and the arithmetic on ninety days at £2,500 gets to a number that closes a small firm.

The certificate itself has to be displayed where employees can read it. Since 1 October 2008 electronic display is allowed, provided your people know where it is and can actually get to it. Since the same date there has been no legal requirement to keep expired certificates, and HSE nonetheless advises keeping a complete record anyway, because industrial disease claims surface decades after the exposure that caused them. A mesothelioma claim in 2046 will be traced through the Employers' Liability Tracing Office to whichever insurer was on risk in 2026, and if nothing can be found, the claim lands on the company, or on the person who was the company.

Who counts as your employee, which is the question that actually costs money

HSE40 is unusually direct about this, and it is worth reading the exact framing:

It does not matter whether you usually call someone an employee or self-employed or what their tax status is. Whether you choose to call your contract a contract of employment or a contract for services is largely irrelevant. What matters is the real nature of your relationship with the people who work for you and the nature and degree of control that you have over the work they do.

Read that against how a UK site actually runs. Your CIS subcontractor is self-employed for tax. That has no bearing on whether they are your employee for the purposes of the 1969 Act. The two tests are unrelated, and the CIS deduction is routinely assumed to settle the question. It settles a different question.

HSE sets out the indicators in two lists. You may need EL cover for someone where:

• you deduct National Insurance and income tax from what you pay them
• you have the right to control where and when they work and how they do it
• you supply their work materials and equipment
• you have a right to any profit they make
• you require that person only to deliver the service, and they cannot send a substitute
• they are treated the same way as other people you employ

You may not need it where:

• they do not work exclusively for you and operate as an independent contractor
• they supply most of the equipment and materials they need
• they are clearly in business for their own benefit
• they can send a substitute when they cannot do the work themselves
• you do not deduct income tax or National Insurance, although HSE adds that someone self-employed for tax may still be an employee for other reasons

The insurance market compresses those lists into two phrases you will meet on every renewal form.

A labour-only subcontractor turns up with hand tools, works under your direction, uses your materials and your plant, and is paid by the day or by the metre. On HSE's indicators this person sits squarely in the first list. They are treated as your employee for EL purposes and they must be declared on your policy, and the premium is rated on what you pay them.

A bona fide subcontractor prices a defined package of work, supplies their own plant and materials, works unsupervised to their own method, invoices against a quotation, and holds their own public and employers' liability cover. They sit in the second list, and they are declared separately, usually at a much lower rate, on the basis that you hold copies of their certificates.

Insurers ask you to split your subcontractor spend between those two categories at every renewal, and they ask because the answer changes the premium. Declaring a labour-only gang as bona fide is the classic way a UK contractor discovers, at the worst moment, that the person on the stretcher was not on the policy.

Here is the belief this runs into, in an answer given to a UK self-builder who asked a construction forum what he owed the people he was taking on labour-only:

"Nothing other than your site insurance covering your liability ALL Self employed trades should have there own public liability. While you are employing them to do a task There not employees and it's up to them to sort there tax out Even if you pay them in cash"

nod, on the BuildHub forum

The instinct behind it is understandable, and the first three words are where it costs money. Public liability does not respond to a claim by the injured worker. The person carrying the risk on a labour-only arrangement is the person giving the directions.

The exemptions, and how narrow they are

HSE40 lists the ones that reach a small construction business:

• A sole trader with no employees. No employees, no duty. The 1969 Act only bites on employers.
• A limited company employing only its owner, where that employee also owns 50% or more of the issued share capital. This is the single-director contractor limited company, and it is the exemption a one-person firm is most likely to be relying on without having looked it up. Take on one labourer and it evaporates the same day.
• A family business where all employees are closely related to you as husband, wife, civil partner, parent, grandparent, step-parent, child, grandchild, step-child, sibling or half-sibling, under section 2(2) of the Act. HSE is explicit that this exemption does not apply to family businesses incorporated as limited companies. A father and son partnership can rely on it. The same father and son inside a limited company cannot.

Being exempt from the Act and being acceptable to a main contractor are different things. A principal contractor's PQQ will still ask for an EL certificate, and the honest answer, that you are a single-director company relying on the 50% shareholder exemption, is one a good compliance manager accepts and a rigid one does not. Buying the cover anyway is often cheaper than the argument.

The conditions your insurer is not allowed to impose

Regulation 2 of SI 1998/2573 prohibits a set of policy conditions outright, and it is worth knowing because it is more generous than its reputation on site. Your EL insurer cannot refuse to pay compensation purely because you failed to protect employees against injury, failed to keep specified records, failed to do something they told you to do, or failed to meet a legal requirement connected with protecting your employees. The injured worker gets paid.

What the insurer can do, and HSE40 says so plainly, is come after you afterwards to recover what they paid, if your failure to meet your health and safety duties caused the claim. The compensation is guaranteed to the worker. It is not guaranteed to be free to you. That is the mechanism that quietly links your construction phase plan to your balance sheet, and it is covered in CDM 2015 on a domestic job.

Contract Works, and the JCT clause that decides who buys it

Public liability covers what you damage that belongs to other people. Contract works insurance, also sold as Contractors' All Risks, covers the thing you are building: the partly-built works, materials on site, temporary works, and site huts, against fire, flood, storm, theft, vandalism, impact and accidental damage.

It does not cover the existing building you are working on. That is the gap that swallows domestic extension jobs, because on a rear extension the two are physically joined and the client assumes their household policy is dealing with it.

JCT resolves this with a set of named insurance options, selected in the Contract Particulars. On the Standard Building Contract and Design and Build they sit in Schedule 3 and are referred to by letter. On the Minor Works forms, the equivalent choice sits in the insurance section of the conditions. The letters are worth memorising because the entire question of who pays for a burnt-out extension turns on which one was ticked.

Two features of these policies matter more than the letter.

Joint names. Both parties are insured under the same policy for their own interest. The practical effect is that the insurer cannot pay the employer and then pursue the contractor by subrogation for the same loss, because you cannot subrogate against your own insured. A single-name policy in the employer's name leaves you exposed to exactly that.

Option C on a domestic job. Option C obliges the homeowner to maintain joint-names cover on their existing house and its contents. Household buildings insurers frequently decline to endorse a builder onto a domestic policy, which is why JCT provides an alternative arrangement in the Contract Particulars and why the gap is so often simply left open. Raise it at contract stage, in writing, and get the answer recorded. Discovering after a fire that the house itself was uninsured is a conversation with no good version.

The non-negligence clause, for the jobs that move the ground

Standard public liability responds when you were negligent. A neighbouring property can be damaged by work that was carried out perfectly: underpinning, a basement dig, a party wall, piling next to a Victorian terrace. The employer is still liable to the neighbour, and no negligence policy answers.

JCT clause 6.5.1 fills that. It is a joint names policy, taken out by the contractor on the employer's behalf when the Contract Particulars require it, with the employer bearing the premium and the excess because it is priced into your tender. The named perils are specific: collapse, subsidence, heave, vibration, weakening or removal of support, and lowering of groundwater.

If your quote involves any of those six words, check whether the Particulars have switched clause 6.5.1 on. Which contract you are working under, and where its insurance provisions sit, is set out in which contract a UK builder signs.

Tools and plant: your own, and the hire company's

Your own tools. Typically £5,000 to £10,000 of cover in total, with a single-article limit inside it, which is the number that decides whether your £3,200 laser level is fully covered. Insurers vary on the condition that produces most disputes, theft from a locked vehicle overnight. Some exclude it outright between fixed hours. Some cover it with a higher excess. Tradesman Saver, for instance, publishes cover for tools stolen from an unattended locked vehicle including overnight, with a higher excess applying, while excluding theft where the vehicle was unlocked or reasonable care was not taken. Two policies at the same price can differ completely on this, so read the overnight clause before you compare premiums.

The second condition worth reading is the sum insured. Tools cover is usually written subject to average, which means insuring £6,000 of kit for £3,000 gets you half of any claim, not the first £3,000 of it. Value the van contents honestly once a year.

Hired-in plant. When you take a mini digger, a telehandler or a tower on hire, the hire company's terms make you responsible for it from the moment it leaves their yard. That responsibility has two halves, and small firms consistently insure only the first:

1. Physical damage to the plant, up to its replacement value.
2. Continuing hire charges, which is the daily hire rate the company keeps charging while the machine is written off, being repaired or being replaced. On a long-lead item that can exceed the value of the machine.

Hired-in plant liability is a specific extension on a trade or contract works policy, and the limit needs to be set against the most expensive item you are likely to have on hire at once, not the one on hire today. The hire company's own damage waiver is usually the more expensive way to buy the same thing, day for day, but it is instant, which is worth something at 7am on a Monday.

Professional Indemnity: the moment you take on design

The instant you sign anything with a design element in it, your exposure changes character. You are no longer only liable for building it badly. You are liable for the advice, and PL does not answer for advice.

Three routes get a small contractor there, and two of them are accidental:

• JCT Minor Works with Contractor's Design (MWD 2024), where a defined portion of the works is yours to design.
• A Contractor's Designed Portion written into a larger contract, which is often just the steel connections, the roof structure or the M&E layout.
• A Design and Build contract (JCT DB 2024), where the whole design responsibility transfers.

The contractor who says "I don't do design" and then details the beam sizes with the steel fabricator has taken on design. So has the one who selected the insulation build-up.

Three features of PI wordings decide whether the cover is real:

It is written claims-made. The policy that responds is the one in force when the claim is made against you, not the one in force when you did the work. Let the policy lapse and the cover disappears retrospectively for everything you have ever designed. That is what run-off cover exists for, and it is why a contractor winding up a company after thirty years still buys PI for several years afterwards.

Fitness for purpose is usually excluded. PI insures the failure to exercise reasonable skill and care, which is the common law duty. A contract clause promising that the works will be "fit for purpose" imposes a strict, absolute obligation, and standard PI wordings exclude it. Signing that clause creates an uninsured liability, and it is the single most valuable amendment to argue for in a subcontract. Liquidated damages are commonly excluded on the same principle.

Limits start low. Entry limits are around £250,000, rising to £5m for design and build work. The limit is normally in the aggregate, which on a claims-made policy with a long tail is a meaningfully smaller promise than the same number written any one occurrence.

The 15-year clock, and where it came from

Section 135 of the Building Safety Act 2022 inserted section 4B into the Limitation Act 1980, and it rewrote how long a builder's exposure on a dwelling lasts.

Section 1 of the 1972 Act puts a duty on anyone taking on work for the provision of a dwelling to do it in a workmanlike or professional manner, with proper materials, so that the dwelling is fit for habitation when completed. Section 2A, which came into force on 28 June 2022, extends the same duty to work done to an existing dwelling. That second one is the change that reaches ordinary builders, because it covers refurbishment and extension work rather than only new build.

Fifteen years. Held against a claims-made policy, that is fifteen years of renewals you have to keep paying for work you finished in year one, and it is the reason PI run-off is not an optional extra for anyone who has ever designed a beam.

There is no workers' compensation scheme here

A reader arriving from Ontario or from a US state is looking for the thing that does not exist. There is no WSIB, no state fund, no premium classes, no clearance certificate to hand a general contractor before you get paid. Great Britain did not build one. What sits in that space is three separate systems that do not talk to each other, and only one of them is arranged by you.

There is a state no-fault layer, and it is smaller than a North American reader expects. Industrial Injuries Disablement Benefit is paid by the DWP, tax-free and non-contributory, to people injured or made ill by their work. The assessment threshold is 14% disablement, and the weekly rates run from £46.78 at 20% to £233.90 at 100%. Two limits define it: it is a benefit to the worker rather than a levy on the employer, so it does nothing about the civil claim, and you cannot claim it if you were self-employed. In an industry that runs on CIS, that exclusion covers a large share of the people on site.

Alongside it sits Statutory Sick Pay, at up to £123.25 a week for up to 28 weeks, paid by the employer to employees. The self-employed subcontractor gets neither.

Follow the chain through and the shape becomes clear. The injured labour-only subcontractor has no IIDB, no SSP, and one route to being made whole: a negligence claim against whoever was directing the work. That is you, and the policy that answers is your employers' liability policy, whether or not you thought of him as an employee. This is why the labour-only test is not a paperwork question. It is the whole compensation system for that person.

One extension, nine ways it goes wrong

A £68,000 single-storey rear extension for a homeowner in Bristol. You are the sole contractor, you have one employed carpenter and a labour-only groundworker on day rate, and the client's architect has left the steel connection design to you.

Nine events, seven policies, and only one of them the law will fine you for missing. The other eight are decided months earlier, by which boxes were ticked in a contract that was signed without being read closely.

A specialist construction broker earns their commission on exactly this: the labour-only split, the aggregate wordings, and the clause 6.5.1 question. Take them the contract, not just the trade description.

What it costs

Nothing here is charged by AEC Stack. Registering the covers you hold, storing the certificates and sending them to a main contractor who has asked for them are part of the platform.

There is no monthly subscription. The platform fee is 2.5% of each invoice processed through AEC Stack, taken when the invoice is paid, so a quiet month costs nothing. Your certificates sit against your business record with their renewal dates, your subcontractors' certificates sit against the subcontractor, and when a pre-qualification pack lands on a Tuesday asking for all of it by Friday, it is one send rather than an afternoon of searching email.

Before you accept the next subcontract, find the insurance clause, read the limit and the words after it, and put your own certificates and your subcontractors' certificates in one place at your business record.