Types Of Construction Contracts In The UK: A Practical Guide

If you run a small construction business, take on subcontract work, or manage building projects for clients, your contract is doing a lot of heavy lifting.

It sets expectations, controls cashflow, allocates risk, and (when things go wrong) becomes the document everyone points to.

In this guide, we’ll walk through the main types of construction contracts used in the UK, when each one tends to work best, and what to watch out for before you sign. The goal is simple: help you choose a contract structure that protects your business from day one, without overcomplicating your projects.

Why Your Contract Type Matters In Construction (More Than In Most Industries)

Construction projects are high-risk by nature. Even “small” jobs can involve:

• multiple parties (client, main contractor, subcontractors, suppliers)
• tight timelines and sequencing issues
• variations and scope creep
• health and safety obligations
• late payments and cashflow pressure
• quality disputes, snagging, and defects

The type of contract you use influences how those risks are shared and how disputes get resolved. Two contracts might cover the same job, but lead to very different outcomes if (for example) there’s a delay, the price of materials jumps, or the client changes their mind mid-way.

It’s also worth remembering that a contract doesn’t have to be a massive 60-page document to be enforceable. But it does need to be clear, consistent, and tailored to how you actually run your projects. If you’re putting together your agreements, getting help with Contract Drafting can save you serious time and stress later.

The Main Types Of Contracts In Construction (And When To Use Each)

There are lots of ways to categorise the common contract types used in UK construction, but most projects sit within a few familiar pricing and risk models. Below are the main options you’ll see in practice.

1) Fixed Price (Lump Sum) Contracts

A fixed price contract is exactly what it sounds like: you agree to deliver a defined scope of works for an agreed price.

When it works well:

• the scope is stable and clearly specified (drawings, specification, schedule of works)
• the site conditions are known (or the risk is manageable)
• you want predictable budgeting for the client and predictable margin for you

Typical risks to watch:

• scope creep - small “can you just…” requests that add up
• unclear exclusions - disputes about what was “included”
• price inflation - materials/labour costs rise after pricing
• programme risk - delays can erode profit fast

Practical tip: If you’re using a fixed price model, your variations clause is critical. Make sure you have a clear process for approving variations in writing (including time extensions and cost adjustments) before the work is carried out.

2) Measurement / Re-Measurement Contracts (Bill Of Quantities)

In a measurement contract, the job is priced using rates (for example, per m², per metre, per unit), and the final contract sum is adjusted depending on what is actually measured on site.

When it works well:

• the scope is broadly known, but quantities may change
• groundworks, civils, or refurbishment where unknowns are common
• projects where a bill of quantities or schedule of rates is realistic

Typical risks to watch:

• disputes about measurement method and evidence
• admin burden (record-keeping, site instructions, valuation)
• cashflow issues if interim valuations are delayed or challenged

Practical tip: Keep your site records tight. Photos, daily diaries, delivery tickets, and sign-offs can become crucial if you need to justify measurements or payment claims.

3) Cost Plus Contracts

A cost plus contract means the client pays your actual costs (labour, materials, plant, subcontractors) plus an agreed fee or percentage margin.

When it works well:

• the scope isn’t fully defined at the start
• there’s urgency (you need to start before everything is finalised)
• refurbishments where hidden conditions are likely

Typical risks to watch:

• client mistrust if records aren’t transparent
• disagreements about what counts as “cost” (overheads, travel, supervision)
• less incentive (in the client’s eyes) to control costs unless carefully managed

Practical tip: Set clear boundaries around:

• what documentation you’ll provide (timesheets, invoices, receipts)
• how often reporting happens
• what is included in “costs” vs covered by your fee
• any caps or budgets (for example, “cost plus but not exceeding £X without written approval”)

4) Time And Materials (T&M) Contracts

Time and materials is common for small works, reactive maintenance, and short-notice jobs. You charge an hourly/daily rate plus materials, often with a markup.

When it works well:

• the job is difficult to price accurately upfront
• the work is intermittent or investigative (fault-finding, repairs)
• you need flexibility for changing site conditions

Typical risks to watch:

• client disputes about time spent or productivity
• unclear daywork rates, overtime, or call-out charges
• payment delays if timesheets aren’t signed off

Practical tip: Build in a simple sign-off process: daily timesheet approvals and clear material pricing rules. It’s a small admin step that can prevent a big payment argument later.

5) Target Cost / Pain-Gain Contracts (Less Common For Small Jobs, But Worth Knowing)

In a target cost model, you agree an initial target budget. If the final cost comes under the target, savings may be shared; if it goes over, the “pain” is shared based on an agreed formula.

When it works well:

• longer projects where collaboration matters
• clients who want cost transparency and incentives for efficiency
• projects with uncertainty but shared commitment to manage it

Typical risks to watch:

• complex valuation and reporting requirements
• disputes about what cost overruns are “allowable”
• risk of arguments if the contract formula isn’t crystal clear

Practical tip: If you’re considering anything like this, get the drafting checked. These models can work well, but only if the mechanics are genuinely clear and workable day-to-day.

Common Construction Contract Structures (Who’s Contracting With Who?)

When people talk about “types of contracts in construction”, they’re sometimes referring to pricing models (like fixed price vs cost plus), but just as often they mean the structure of who is engaged and who holds the risk.

Here are the most common structures small businesses deal with.

Main Contractor And Subcontractor Agreements

If you are the main contractor, you’ll typically have one contract with the client, and separate subcontract agreements with each trade.

If you are a subcontractor, you’ll usually be engaged by the main contractor (or another subcontractor), and your rights to payment, variations, extensions of time, and dispute resolution will depend heavily on that subcontract.

For subcontract relationships, it’s often worth having a dedicated Subcontractor Agreement rather than relying on informal emails and purchase orders (which can leave big gaps around scope, timing, and liability).

Design And Build vs Traditional (Design-Bid-Build)

Even on smaller projects, the question comes up: who is responsible for design?

• Traditional: the client appoints a designer/architect separately, and the contractor builds to that design.
• Design and build: the contractor takes responsibility for both design (or elements of design) and construction.

Why this matters: design responsibility can significantly increase your risk. If you’re responsible for design, you may be on the hook if something is non-compliant, doesn’t meet the agreed specification, or otherwise fails to meet the contractual standard of care (which can vary depending on the contract and the role you’ve agreed to take on).

Practical tip: If you’re stepping into any design responsibility, your contract should be explicit about:

• what “design” you’re responsible for (and what you aren’t)
• what standards apply
• what approvals are required from the client
• how you’ll manage changes to the design

Labour-Only And Supply-Only Arrangements

Some smaller operators work labour-only (you provide the labour, the client supplies materials) or supply-only (you provide materials/plant without installation).

These can be totally legitimate - but only if your paperwork matches reality.

Common pitfalls:

• unclear responsibility for defective materials (who chose them, who stored them, who installed them)
• insurance gaps (for example, tools/materials on site)
• disputes about delays caused by late client-supplied materials

Practical tip: Spell out who is responsible for procurement, delivery, storage, and wastage. A short clause can save a long argument.

Key Clauses To Get Right (No Matter Which Contract Type You Choose)

You can pick the best contract model in the world, but if your core clauses are vague, you’re still exposed.

Below are the clauses we often see causing problems for small construction businesses - and what to aim for instead.

Scope Of Works And Specifications

Most disputes start with “that’s not included” vs “yes it is”. Your contract should include a clear scope, plus any drawings/specifications, and ideally a schedule of works.

Practical tip: Include both:

• inclusions (what you will do)
• exclusions (what you won’t do, and what would be a variation)

Payment Terms And Late Payment Protections

Cashflow is everything in construction. Your contract should clearly state:

• the price and when invoices are issued
• payment due dates
• deposit requirements (if any)
• retention (if any) and release conditions
• what happens if payment is late (interest, suspension rights)

Practical tip: Consider whether you need a right to suspend works for non-payment (and the process to do it properly). This can be a powerful leverage point when used carefully.

Variations (The “Change Control” Clause)

Variations are normal. The problem is when they’re not documented.

A good variations clause sets out:

• how a variation is requested
• how it’s priced
• how time extensions work
• when the client must approve it

If you’re doing any bespoke drafting, getting support with Clause Drafting is often worthwhile here, because one-size-fits-all wording rarely matches how variations happen on site.

Delay, Extensions Of Time, And Liquidated Damages

Construction timelines are rarely perfect, and delays aren’t always your fault (weather, access issues, other trades, client changes).

Make sure the contract deals with:

• what counts as a compensable delay
• how you notify delays
• how extensions of time are granted
• whether there are “liquidated damages” (a pre-agreed amount payable for delay)

Practical tip: If a contract includes liquidated damages, check that the delay mechanism is fair and workable. Otherwise, you can end up carrying risk you can’t control.

Limitation Of Liability

Without clear limits, your potential liability might be far higher than the profit you’ll ever make on the job.

Depending on the project, you might limit liability by:

• capping it to a fixed amount (for example, the contract price)
• excluding certain types of loss (like indirect or consequential loss)
• limiting timeframes for claims

This is a technical area, and the right approach depends on the job, the parties, and your insurance position. It can help to review limitation of liability wording to understand what’s common in UK commercial contracts and what might be appropriate for your projects.

Defects, Warranties, And Snagging

Your contract should set expectations about:

• snagging process at practical completion
• defects liability period (if any)
• what’s excluded (fair wear and tear, misuse, third-party works)
• how the client reports defects and your timeframe to respond

Practical tip: Make sure you control the remedy process (for example, you get the right to return and rectify) rather than being forced into open-ended refund/compensation demands.

Execution And Admin: How To Make Sure Your Construction Contract Holds Up

A contract is only helpful if you can rely on it when it counts. That means thinking about execution and day-to-day admin - not just the legal wording.

Do You Need A Deed Or A Simple Contract?

Most construction engagements are signed as a standard contract, but sometimes parties want a deed (for example, for certain warranties or where there’s a reason to avoid the need for “consideration”). The formalities can be stricter.

If you’re unsure about signing formalities, it’s worth checking what’s involved in executing deeds so you don’t accidentally end up with an improperly signed document.

Who Can Sign And Who Can Witness?

For small businesses, it’s common for one director/owner-manager to sign agreements. But the rules can differ depending on:

• whether you’re a sole trader, partnership, or limited company
• whether the document requires witnessing
• whether it’s being signed on behalf of someone else

If a contract needs witnessing (common with deeds), make sure you know who can witness a signature so the signing is valid and you don’t have to redo it later.

Keep Your Paper Trail Clean

Even the best contract can’t save you if your project admin is messy. A few habits make a big difference:

• confirm scope and exclusions in writing before starting
• log instructions and variations as they occur
• use written approvals (for example, email) where your contract allows it
• keep records of deliveries, timesheets, and site conditions
• issue invoices in line with the contract (and follow up promptly)

These aren’t just “nice to have” admin steps - they’re often the evidence you need if a payment dispute or defects claim appears months later.

Key Takeaways

• The main construction contract types usually fall into a few pricing models: fixed price, re-measurement, cost plus, time and materials, and (less commonly) target cost structures.
• The “right” contract type depends on how defined the scope is, how much uncertainty is in the project, and who can realistically control time and cost risks.
• No matter the contract model, your scope, payment terms, variations process, delay provisions, and limitation of liability clauses are where most disputes are won or lost.
• If you’re a main contractor engaging trades, or a subcontractor taking work from a head contractor, a dedicated subcontract agreement can help keep responsibilities and payment rights clear.
• Getting signing formalities right matters - especially where deeds or witnessing requirements apply.
• Templates can be a useful starting point, but construction contracts usually need tailoring to the project, your insurance position, and how you actually operate day-to-day.

This article is general information only and isn’t legal advice. If you’d like advice for your specific project, it’s best to speak to a lawyer.

If you’d like help choosing the right contract structure for your projects, or you want a construction contract drafted or reviewed before you sign, you can reach us at 08081347754 or team@sprintlaw.co.uk for a free, no-obligations chat.