The Construction Industry Scheme (CIS) is a crucial part of the UK construction tax system. Whether you are a contractor, subcontractor, or both, understanding CIS rules, CIS registration, and your obligations to HMRC is essential for staying compliant and avoiding penalties. In this guide, we break down what CIS is, who needs to register, what work is covered, exemptions, and how to claim CIS refunds.
What Is the Construction Industry Scheme (CIS)?
The CIS is a tax scheme designed by HMRC to regulate payments from contractors to subcontractors in the construction sector. Contractors must deduct tax from subcontractor payments and submit these deductions to HMRC. This ensures tax compliance within the construction supply chain.
Key CIS responsibilities include:
- Registering with HMRC
- Deducting CIS tax from subcontractor payments
- Submitting monthly CIS returns
- Keeping accurate CIS records
What Work Is Covered Under CIS?
HMRC specifies that CIS covers most UK construction operations. This includes:
- Site preparation and demolition
- Building work, repairs, renovations, and decorating
- Installation of heating, lighting, water, power, and ventilation systems
- Internal cleaning after construction work
If your business performs construction-related activities, it is likely subject to CIS regulations.
Which Businesses Must Register for CIS?
The CIS applies to contractors, subcontractors, and businesses that act as both.
CIS Contractors
You are considered a contractor if:
- You pay subcontractors to carry out construction work
- Your non-construction business spends more than £1 million per year on construction (deemed contractor)
Contractors must legally register for CIS before hiring subcontractors.
CIS Subcontractors
You are a subcontractor if you carry out construction work for a contractor.
Subcontractor registration is optional but recommended because:
- Registered subcontractors pay 20% deductions
- Unregistered subcontractors pay 30% deductions
- Subcontractors with gross payment status pay 0% deductions
CIS Exemptions: Who Doesn’t Need to Register?
Not all work falls under CIS. You may be exempt if your services involve:
Professional or equipment-only services:
- Scaffolding hire (equipment only)
- Architecture or surveying
- Carpet fitting
Specific clients:
- Charities
- Trusts
- Schools via local education authorities
Certain property types:
- Work done on your own business premises (not for sale or rental)
Small CIS contracts:
- Work under £1,000 (excluding materials), subject to HMRC approval
Understanding CIS exemptions helps businesses avoid unnecessary registration.
How to Register for CIS as a Contractor?
To comply with HMRC CIS rules, contractors must register before paying subcontractors. This involves:
- Registering as an employer with HMRC
- Obtaining a PAYE reference number
- Verifying subcontractors through HMRC’s CIS service
- Making CIS tax deductions and submitting monthly returns
Failure to register or file returns leads to penalties starting at £100 and increasing over time.
How to Register for CIS as a Subcontractor?
Subcontractors can register for CIS online using a Government Gateway account and UTR. New subcontractors can register for Self Assessment and CIS at the same time.
Benefits of CIS registration include:
- Reduced deduction rates
- Better cashflow
- Compliance with HMRC
Subcontractors may also apply for gross payment status, allowing full payment without CIS deductions—subject to turnover and compliance checks.
Benefits of CIS for Contractors and Subcontractors
For subcontractors:
- Lower deduction rate (20% vs 30%)
- More predictable tax payments
- Reduced risk of large tax bills at year-end
For contractors:
- Compliance with HMRC
- Ability to verify subcontractor status
- Proper tax deductions and reduced penalties
CIS helps both parties operate within HMRC guidelines while improving financial control.
How to Claim a CIS Refund?
For most sole traders, the standard way to claim a CIS refund is through a self assessment tax return
After the tax year ends on 5 April, you submit your return declaring:
- Your total income
- Allowable business expenses
- CIS tax deductions shown on your statements
HMRC will confirm the over payment and process your CIS refund.
Use Our calculator to know amount of your CIS deduction.
How to Deregister or Cancel CIS Registration?
You must inform HMRC if:
- You stop trading
- You no longer use subcontractors
- Your business structure changes
- A contractor passes away
Businesses can request temporary inactivity if they plan to resume CIS operations later. Monthly returns must continue until HMRC confirms deregistration.
Need CIS Advice or Support?
Whether you need help with CIS registration, CIS monthly returns, CIS refunds, or understanding how CIS applies to your construction business, professional guidance can save time and prevent costly mistakes.
At GM Accountants & Tax Consultants, our team of qualified accountants can support and guide you with CIS Tax returns and other tax matters, at competitive and affordable prices. For CIS Subcontractors, we have special offer you do not need to pay until you get your refund. Please feel free to contact us for expert advice. If you are unable to visit our office, we can arrange a video call at a time that suits you. For further information, email us at admin@gmtaxconsultants.co.uk or call us on 020 3773 4123.
Disclaimer:
The information provided in this blog is for general informational purposes only and does not constitute professional accounting or tax advice. As individual circumstances may vary, readers are advised to contact us directly for advice tailored to their specific financial or tax situation.
