Is Construction Arbitrage Legal in Ireland?

Construction arbitrage is legal in Ireland. Winning the prime contract, subcontracting the physical work to specialist trades, and keeping the spread between the two prices is how Irish construction has always operated. The compliance requirements are Revenue's Relevant Contracts Tax and, from 2026, mandatory CIRI registration.

I run this model. Ireland is a distinct jurisdiction from the UK - same island, very different compliance layer. The RCT scheme is Ireland's equivalent of the UK's CIS, and it works differently in some important ways. Here is exactly what the law asks of you in Ireland.

Why construction arbitrage is legal in Ireland#

Construction arbitrage is standard main contracting. You hold the prime contract with the client, subcontract the physical work to vetted specialist trades, and keep the margin between the two sides of the deal. That structure is how every major residential development, commercial fit-out, and large renovation project is delivered in Ireland.

No Irish law requires a main contractor to self-perform any portion of a construction contract. The law is not concerned with who is swinging the hammer. It is concerned with whether the entity holding the prime contract is complying with its tax obligations and - increasingly from 2026 - whether it is registered on the Construction Industry Register Ireland.

The model is legitimate. What makes it legitimate is the compliance stack underneath it.

CIRI - Ireland's mandatory contractor registration from 2026#

For much of Ireland's modern construction history, there was no mandatory general contractor licence. That changed in 2026.

The Construction Industry Register Ireland (CIRI), managed by the Construction Industry Federation on behalf of the Irish government, became a statutory register in 2026. Under the Building Control Amendment Regulations, providers of building services in regulated categories are now required to be registered on CIRI before they can lawfully carry out that work.

What this means for the construction arbitrage operator: if you are the main contractor holding the prime contract for a project in a launched CIRI division, you must be registered. The obligation falls on the entity entering the contract, not only on the person doing the physical work.

The rollout is phased, division by division, with the first mandatory categories being:

• Housing developments of ten or more units
• Apartments
• Duplex and triplex buildings

Applicants have twelve months after each division is formally launched to achieve registration. The requirement will extend to further categories as additional divisions are launched. Check cif.ie/ciri for the current list of active mandatory divisions - this is live legislation being implemented in stages and the list will grow.

CIRI registration requirements include demonstrating a business framework, appointing a competent person with the appropriate knowledge and skills for the division, maintaining tax compliance, and holding required levels of insurance. It is not a test of whether you personally pick up a tool - it is a test of whether your business is properly structured to deliver construction outcomes.

For categories not yet covered by a launched CIRI division, there is currently no mandatory general contractor licence. That position will change as more divisions go live.

RCT - the compliance that matters most#

Relevant Contracts Tax (RCT) is Ireland's mandatory withholding tax system for construction, forestry and meat-processing. It is administered by Revenue and is the Irish equivalent of the UK's CIS scheme, though there are meaningful differences in how it operates.

If you pay a subcontractor for construction work in Ireland, you are a principal contractor and RCT applies to you from the moment of your first sub payment. There is no minimum project size, no threshold, and no grace period.

Register before your first sub payment#

Register with Revenue before you make any payment to a subcontractor. The registration form is:

• TR1(FT) for sole traders and partnerships
• TR2(FT) for companies

Both forms are available through Revenue's online registration service. All subsequent RCT compliance runs through Revenue's online system, ROS (Revenue Online Service).

Notify Revenue of each contract before payment#

Unlike some tax systems where you report after the fact, RCT requires you to notify Revenue of a relevant contract before you make any payment under it. Revenue then returns the applicable deduction rate for that subcontractor.

The three rates are:

Subcontractor status	Deduction rate
Clean compliance record (gross payment status)	0%
Registered but imperfect record	20%
Unregistered or poor record	35%

The deduction is made from the gross payment to the subcontractor and remitted to Revenue. It counts toward the subcontractor's own tax liability - you are not taking money from the sub; you are forwarding their tax payment to Revenue.

File returns and pay deductions#

After each period, you submit a deduction summary through ROS - either monthly or quarterly depending on your volume of payments. The summary covers all contracts notified and all deductions made in the period.

The penalty picture: if you make a payment without first obtaining a deduction authorisation from Revenue, you face a penalty of 3%, 10%, 20% or 35% of the relevant payment - the rate applied depends on the circumstances. Revenue has been actively increasing its audit activity in the construction sector because RCT errors are relatively easy to identify and the yields are high. The Revenue page on penalties for principal contractors sets out the detail.

VAT and the domestic reverse charge#

Once your taxable turnover reaches €42,500 per year for services (or €85,000 for goods), you must register for VAT with Revenue. In construction, a single mid-sized contract can hit the services threshold in one payment. Register before you cross it, not after.

The VAT rate on most construction services in Ireland is 13.5% - not the standard 23%. The 13.5% reduced rate applies to the services element of construction, repair, maintenance and installation work. Standard 23% applies to goods-only supplies, scaffolding hire, and contracts where materials account for more than two-thirds of the total value.

Once you are VAT-registered and supplying construction services B2B, the domestic reverse charge applies in most cases. Under Ireland's reverse charge rules for construction, your subcontractors do not add VAT to their invoices to you as the principal contractor. Instead, you account for the VAT directly on your VAT return - the same mechanism the UK uses through its own domestic reverse charge for construction.

The practical effect: you receive sub invoices without VAT, and you declare the VAT on the purchase yourself. This was introduced to prevent VAT fraud in the construction supply chain, where contractors collected VAT from clients and never remitted it.

Business registration and tax#

Register your business entity with the Companies Registration Office (CRO) before you take your first contract if you are operating as a limited company. Sole traders register for Income Tax through Revenue.

Limited company: register with the CRO, then register for Corporation Tax with Revenue within the required timeframe. Profits are subject to Corporation Tax; the standard rate is 12.5% on trading income.

Sole trader: register for Income Tax via Revenue. Profits are taxed under the personal income tax system plus PRSI and USC. The exact rates depend on your total income - get an accountant from the start.

Subcontractor payments are a legitimate business expense, subject to RCT deduction as above, and run through your normal accounts. They do not go through payroll.

Insurance requirements#

Public liability insurance is not a legal requirement in Ireland. There is no Irish equivalent of a statute mandating it. However, you will not win serious construction work without it. Commercial clients, developers, and local authority frameworks universally require a minimum level of public liability cover - typically €6.5 million and upward for contractor-facing work, with larger commercial and public sector projects requiring substantially more. Treat it as the cost of entry.

Employers' liability insurance is also not legally compulsory in Ireland - unlike the UK, there is no statute that mandates it. However, the Safety, Health and Welfare at Work Act 2005 places a statutory duty of care on every employer. In practice, every construction contract and most commercial clients require employers' liability cover to be in place before work begins. Operate without it at your own risk.

Your subcontractors carry their own insurance and are responsible for their own public liability cover on site. Build proof of current insurance into every subcontract agreement as a condition of starting work. Do not let any sub on site without it.

What actually makes it non-compliant#

Construction arbitrage is not illegal in Ireland. What gets operators into trouble:

• Paying subcontractors without RCT registration - Revenue can back-assess penalties on the full gross amount paid, not just the missed deduction
• Paying at the wrong deduction rate - the rate Revenue returns when you notify the contract is the rate you apply; applying a lower rate creates a shortfall Revenue collects from you, not the sub
• Failing to notify Revenue of contracts before payment - the notification must come first; paying first and notifying later attracts penalties at 3-35% of the payment
• Operating in a mandatory CIRI division without registration - from the moment a division becomes active you need to be registered to lawfully take prime contracts in that category
• Missing VAT registration when the threshold is crossed - Revenue back-assesses from the date you should have registered, with interest

None of these are ambiguous. They are known requirements with known penalties and known fixes. Set the compliance stack up before the first job and run it the same way on every contract.

Ireland is a good market for this model. Main contracting with subcontracted delivery is how Irish construction has always worked - the construction industry is built on principal contractors and subbies all the way down. The requirement is not to do the work yourself. The requirement is RCT compliance, CIRI registration where applicable, and proper insurance. Get those right and the operation is clean.

The next step#

The global legality overview covers Ireland alongside the US, UK, Canada and Australia in one place. For the contractor licence question in depth across jurisdictions, do you need a contractor licence for construction arbitrage goes into detail. The full setup sequence - entity registration, RCT, insurance, first clients and first subs - is in how to start a construction arbitrage business. And for the tax picture in full, how do taxes work in construction arbitrage covers the mechanics.

If you want the complete system in one place, THE FAMILY SECRET - How Construction Arbitrage Really Works is coming soon.

This is general information, not legal or tax advice. RCT rules, VAT thresholds, CIRI registration requirements and insurance obligations change. Verify current requirements with Revenue Commissioners, the Construction Industry Federation, and a qualified Irish accountant or solicitor before you take work.

Last checked: 12 August 2026.