Construction Operations: What Is In Scope?

Key facts

Construction operations are defined in section 74 of the Finance Act 2004.
In-scope work includes building, civil engineering, alterations, repairs, decorating, demolition, and installing systems like heating and plumbing.
Excluded operations include architecture, surveying, carpet fitting (unless part of a wider contract), and manufacturing off-site.
If a contract covers both included and excluded operations, you may need to apportion the payment.
The location of the work matters — CIS only applies to construction operations in the United Kingdom.

The Legal Definition

Whether a payment falls within CIS depends on whether the work constitutes a “construction operation” as defined in section 74 of the Finance Act 2004. This section provides a detailed list of operations that are included and excluded.^[2]

If the work is a construction operation and the payment is made by a contractor to a subcontractor, CIS applies. If the work falls outside the definition, no CIS deduction is required.

Operations Included Under CIS

The following types of work are construction operations for CIS purposes:^[2]

Category	Examples
Building & construction	Constructing new buildings, extensions, and structures
Alterations & repairs	Renovations, refurbishments, conversions, and maintenance of buildings
Civil engineering	Roads, bridges, railways, harbours, drainage systems, and earthworks
Demolition & dismantling	Tearing down buildings, structures, and equipment
Fitting out & finishing	Joinery, tiling, plastering, flooring (not carpets), glazing, and installing kitchens and bathrooms
Decorating	Interior and exterior painting, wallpapering, and decorative finishes
Systems installation	Heating, lighting, air conditioning, ventilation, power supply, drainage, sanitation, water supply, and fire protection systems
Cleaning (during construction)	Cleaning the inside of buildings as part of construction, alteration, or repair work
Site preparation	Excavation, land clearing, earth-moving, tunnelling, boring, and laying foundations
Roofing	Installing, repairing, or replacing roofs including cladding and weatherproofing
External works	Fencing, landscaping that forms part of construction, and external pipework

Broad interpretation: HMRC takes a broad view of what constitutes “construction operations.” If in doubt about whether specific work is in scope, check the HMRC CIS guidance or seek professional advice.

Operations Excluded from CIS

Certain activities are specifically excluded from the definition of construction operations, even though they may be related to the construction industry:^[2]

Excluded Operation	Reason / Notes
Architecture & design	Professional services, not physical construction work
Surveying & project management	Professional services, not physical construction work
Carpet fitting	Excluded unless it forms part of a larger construction contract
Manufacturing off-site	Making building materials or components at a factory or workshop away from the construction site
Delivering materials	Simply transporting materials to site (no installation labour)
Scaffolding hire (without labour)	Hiring out scaffolding equipment only; the erection and dismantling of scaffolding is in scope
Making artistic works	Sculptures, murals, and other artistic installations
Signwriting & erecting signage	Installing signs on or near buildings
Installing security systems	Burglar alarms, CCTV, and access control (though this area has some grey zones)
Sealing and testing work on gas, water, or electricity	Where the work is carried out by the statutory undertaker (utility company)

Mixed Contracts: Apportioning Payments

Some contracts include a mixture of included and excluded operations. For example, a contract might cover both building work (CIS applies) and architectural design (CIS does not apply).^[3]

In these situations:

If the contract can be split into separate amounts for included and excluded operations, CIS deductions should only apply to the included portion
If the work cannot reasonably be separated, HMRC may treat the entire payment as subject to CIS if the construction element is the dominant purpose
The contractor should agree the split with the subcontractor and keep clear records of how the apportionment was calculated

Tip: Where a contract includes both CIS and non-CIS work, it is good practice to use separate invoices or clearly itemised invoices so the CIS and non-CIS elements are obvious. This makes both the deduction calculation and any HMRC review much simpler.

Common Grey Areas

Some types of work sit near the boundary of the CIS definition. Here are some frequently queried scenarios:^[4]

Cleaning

Cleaning the inside of buildings is in scope only when done as part of construction, alteration, repair, extension, or restoration work. Routine office cleaning or window cleaning after construction is complete is not a construction operation.

Landscaping

Landscaping is in scope if it is part of a construction project (e.g. grounds work for a new housing estate). General garden maintenance and horticultural work on existing properties are not construction operations.

Security Systems

This is a grey area. Installing burglar alarms and CCTV is generally excluded from CIS. However, if the work involves running cabling through walls as part of a broader electrical installation, it may be considered in scope. Each case depends on the specific facts.

Modular and Prefabricated Buildings

Manufacturing modular units off-site is excluded from CIS. However, the on-site assembly, installation, and connection of those units to foundations and services is a construction operation.

Location: UK Only

CIS only applies to construction operations carried out in the United Kingdom (England, Wales, Scotland, and Northern Ireland). Construction work performed overseas — even by UK-based businesses — is outside CIS.^[2]

This means that a UK contractor paying a UK subcontractor for work on an overseas project does not need to make CIS deductions on those payments.

Frequently Asked Questions

Is decorating a construction operation under CIS?

Yes. Painting and decorating are specifically listed as construction operations in the Finance Act 2004. If a contractor pays a subcontractor for decorating work, CIS deductions must be made.

Is scaffolding covered by CIS?

The erection and dismantling of scaffolding (i.e. providing labour to put up or take down scaffolding) is a construction operation. However, simply hiring out scaffolding equipment without labour is not covered by CIS.

Does CIS apply to electrical or plumbing work?

Yes. Installing systems for heating, lighting, air conditioning, ventilation, power supply, drainage, sanitation, and water supply are all construction operations under CIS. This includes electrical and plumbing work.

What about work done outside the UK?

CIS only applies to construction operations carried out in the United Kingdom. Work performed on overseas sites is outside the scope of CIS, even if both parties are UK businesses.

Sources

Construction Industry Scheme (CIS) — GOV.UK
Finance Act 2004, section 74 – Construction operations — legislation.gov.uk
CIS: construction operations (CIS 340) — HMRC
CIS detailed guidance: what counts as construction work — HMRC