Construction operations is the term used in the CIS legislation to define which activities fall within the scheme. Only payments for construction operations are subject to CIS deductions: payments for activities outside the definition are not, even if the payer is a registered CIS contractor.
Activities that count as construction operations include:
- Construction, alteration, repair, extension, demolition and dismantling of buildings and structures.
- Civil engineering works: roads, runways, railways, bridges, harbours and pipelines.
- Installation of systems within buildings: heating, lighting, air conditioning, water, gas, drainage, telecommunications and similar.
- Internal cleaning of buildings as part of a construction project (not routine commercial cleaning).
- Painting and decorating the internal or external surfaces of buildings.
- Operations preparatory to construction: site clearance, groundworks and excavation.
Activities that are excluded from construction operations include:
- Purely professional services: architecture, surveying, engineering design and project management.
- Manufacture or delivery of materials and components where no installation takes place.
- Carpet fitting in a domestic dwelling (not a "building" for these purposes).
- Plant hire where no operator is supplied.
The boundary matters in practice. A structural engineer who only produces drawings is outside CIS; the same engineer who directly supervises a specialist construction operation on site may cross the line. When in doubt, the correct approach is to verify the subcontractor's CIS status through the HMRC CIS online service regardless, because the cost of getting it wrong (making a payment without deduction where one was due) falls on the contractor.
See what construction work is not CIS for a detailed breakdown of excluded activities.