A UK Construction Subcontractor Agreement is a legally binding contract used in England and Wales under which a principal contractor (the party engaged by an employer or developer to carry out a construction project) engages a subcontractor to carry out a specific trade or works package forming part of the wider project. This specialist agreement is distinct from a general subcontractor agreement in that it is specifically drafted to address the regulatory framework governing UK construction contracts, including the statutory payment regime under the Housing Grants, Construction and Regeneration Act 1996 (HGCRA), the health and safety obligations imposed by the Construction (Design and Management) Regulations 2015 (CDM 2015), the tax deduction requirements of the Construction Industry Scheme (CIS), and the domestic reverse charge for VAT.

The HGCRA 1996, as significantly amended by the Local Democracy, Economic Development and Construction Act 2009 (LDEDCA 2009), is the cornerstone of UK construction payment law. It applies to any construction contract as defined in section 104 of the Act and creates mandatory rights in favour of both parties: the right to stage payments where the contract period exceeds 45 days; the obligation to issue Payment Notices and Pay Less Notices within prescribed time periods; the absolute right of either party to refer disputes to adjudication at any time; and the prohibition on ‘pay when paid’ clauses. Construction contracts that fail to include HGCRA-compliant payment terms are supplemented by the Scheme for Construction Contracts (England and Wales) Regulations 1998 (as amended).

The CDM 2015 impose specific health and safety duties on subcontractors as contractors under the Regulations. These include the duty to plan and manage the works safely, to comply with the Construction Phase Plan and the Principal Contractor’s directions, to ensure workers are competent and supervised, and to cooperate with the Principal Designer and Principal Contractor in maintaining the Health and Safety File.

The CIS, administered by HMRC under the Finance Act 2004, requires principal contractors to verify subcontractors’ CIS status and to deduct tax at source from payments for construction work at the applicable rate (0%, 20%, or 30%) as determined by HMRC verification.

Our Construction Subcontractor Agreement template is drafted specifically for use in England and Wales and covers all key legal requirements, including detailed scope of works, programme, subcontract price, payment provisions, CIS deductions, retention, liquidated damages for delay, a rectification period, CDM 2015 obligations, insurance requirements, variation provisions, and statutory adjudication rights.

A formal written Construction Subcontractor Agreement is essential whenever a principal contractor in England or Wales engages a subcontractor to carry out any part of a construction project, regardless of the size of the project or the trade involved. Proceeding on the basis of an oral instruction, a purchase order, or a letter of intent alone creates significant legal risk for both parties and may result in disputes over scope, payment, delay, and defects liability.

A Construction Subcontractor Agreement is needed in the following common circumstances: a principal contractor engaging a specialist trade subcontractor (such as a groundworker, steelwork erector, roofing contractor, mechanical and electrical engineer, or finishing contractor) to carry out a specific works package on a commercial, industrial, or residential development; a principal contractor on a housing development engaging separate subcontractors for the foundation, brickwork, roofing, internal fit-out, and landscaping packages; a civil engineering contractor engaging subcontractors for earthworks, drainage, piling, or road surfacing on an infrastructure project; and a specialist subcontractor sub-contracting part of its works package to a second-tier subcontractor (in which case the specialist becomes the ‘principal contractor’ for the purposes of the sub-subcontract).

A written agreement is especially important for CIS compliance. HMRC requires contractors to verify each subcontractor before making the first payment and to make deductions at the correct rate. A written subcontract that records the UTR, the HMRC verification number, and the CIS deduction rate applicable provides essential evidence of compliance in the event of an HMRC audit.

For projects to which CDM 2015 applies, the subcontractor’s health and safety obligations must be clearly set out in the subcontract. This is particularly important for notifiable projects (those expected to last more than 30 working days with more than 20 workers simultaneously, or to exceed 500 person-days), where the subcontractor must cooperate with the Principal Contractor on the Construction Phase Plan.

The domestic reverse charge for VAT also makes a written subcontract important, as both parties need to agree how the invoicing will be structured and to confirm that the subcontractor will not charge VAT on its invoices where the reverse charge applies.

A comprehensive Construction Subcontractor Agreement for use in England and Wales should address the following key provisions.

Parties and Project Identification — Identify both parties by their full legal names, Companies House registration numbers, and registered or principal addresses. Identify the project by name and reference number, describe the project briefly, and specify the site address. Name the employer or developer if different from the principal contractor, so that the subcontractor understands the contractual chain within which it is operating.

Scope of Subcontract Works — Define the subcontract works package in detail. State the trade or package name (e.g. structural steelwork, roofing, mechanical and electrical). Describe the works with reference to drawings, specifications, and bills of quantities. Specify whether the subcontract is supply-and-fix, labour-only, or a design-and-build subcontract. Clarity about the scope avoids variation disputes and defines the boundary between the subcontractor’s obligations and those of the principal contractor.

CIS Compliance — Record the subcontractor’s CIS registration status, UTR number, and HMRC verification number. State the applicable deduction rate. Require the subcontractor to notify the principal contractor of any change in CIS status. Include the domestic reverse charge provision where applicable.

Programme and Completion — Specify the commencement date and completion date. Require the subcontractor to submit and comply with a programme and to proceed regularly and diligently. Include extension of time provisions for delay caused by the principal contractor, variations, exceptionally adverse weather, or force majeure events.

Subcontract Price and Payment — State the price (lump sum, remeasured, or cost-plus) and the payment schedule (monthly interim valuations, milestone payments, or single payment on completion). Include HGCRA-compliant payment notice and pay less notice provisions. Specify the final date for payment. Confirm VAT treatment, including domestic reverse charge where applicable. Apply the Late Payment of Commercial Debts (Interest) Act 1998 to overdue sums.

Retention — If included, specify the retention percentage (typically 3–5%), the conditions for release (e.g. 50% on practical completion, 50% on expiry of the rectification period), and the interest payable on late-released retention under the Late Payment of Commercial Debts (Interest) Act 1998.

Liquidated Damages — Specify the LAD rate as a genuine pre-estimate of loss for delay beyond the completion date. Confirm compliance with Cavendish Square Holding BV v Makdessi [2015] UKSC 67.

Rectification Period — Specify the period during which the subcontractor must rectify defects (typically 12 months from practical completion). Include the principal contractor’s right to employ others to rectify defects at the subcontractor’s cost if the subcontractor fails to do so.

CDM 2015 Obligations — Set out the subcontractor’s obligations as a contractor under CDM 2015, including the duty to comply with the Construction Phase Plan, submit RAMS before commencing work, ensure CSCS-carded operatives, and report accidents under RIDDOR.

Insurance — Require the subcontractor to maintain public liability insurance (minimum cover as specified), employer’s liability insurance under the Employers’ Liability (Compulsory Insurance) Act 1969, and, where applicable, Contractor’s All Risks (CAR) insurance and professional indemnity insurance.

Variations and Adjudication — Require all variations to be instructed in writing. Confirm the statutory right to refer disputes to adjudication under section 108 of the HGCRA 1996.