Construction Retention Money NZ Legal Obligations

What is Construction Retention Money in NZ

Construction retention money is a percentage of each progress payment that the principal withholds as security for the contractor's performance. Under the adjudication, and suspension rights in construction">Construction Contracts Act 2002 (CCA), retention serves two purposes: ensuring defects are remedied during the defects liability period and providing security for the principal if the contractor fails to complete the work.

The Construction Contracts Act fundamentally changed how retention money must be handled in New Zealand. Prior to the CCA, retention was often treated as the principal's money until release was due. Now, retention money belongs to the payee from the moment it's withheld, creating specific trust obligations for principals.

CCA Retention Money Obligations for Principals

Under Section 18 of the Construction Contracts Act, principals have four key obligations when holding construction retention money:

1. Hold retention money on trust — The money belongs to the payee, not the principal
2. Keep retention money in a separate account — It cannot be mixed with the principal's operating funds
3. Pay interest on retention money — Currently at the prescribed rate set by regulation
4. Release retention money according to contract terms — Usually 50% at practical completion, 50% after defects liability period

These are legal requirements, not suggestions. Failure to comply can result in the principal being liable for penalty interest and potential claims for breach of trust.

Separate Account Requirements

The separate account requirement under Section 18(1)(a) means retention money must be held in an account that is separate from the principal's other funds. This account can be:

• A dedicated retention account for the specific contract
• A general retention account holding funds for multiple contracts (provided proper records are kept)
• An interest-bearing account that meets the trust requirements

The account must be clearly identifiable as holding retention money on trust. Simply earmarking funds in a general account doesn't meet the legal requirement.

Standard Retention Rates and Release Timing

While the Construction Contracts Act doesn't prescribe specific retention rates, industry standards in New Zealand typically follow these patterns:

Contract Type	Typical Rate	First Release	Final Release
NZS 3910 building contracts	5%	50% at practical completion	50% end of defects liability
NZS 3910 infrastructure	5-10%	50% at practical completion	50% end of defects liability
Subcontract agreements	5%	On main contract release	On main contract release
Design and build	2.5-5%	50% at practical completion	50% end of defects liability

The rate and release mechanism must be clearly stated in the contract. If the contract doesn't specify retention provisions, the CCA default provisions apply, which generally prohibit retention unless expressly agreed.

Defects Liability Period Impact

The length of the defects liability period directly affects how long retention money is held. Standard periods are:

• 12 months — Most building works under NZS 3910
• 24 months — Infrastructure and complex mechanical systems
• 36+ months — Some specialised equipment or systems with extended warranty periods

Construction Retention Money Interest Obligations

Under Section 18(1)(c), principals must pay interest on retention money at the rate prescribed by regulation. The current rate is linked to the Official Cash Rate and is reviewed regularly.

Interest must be paid:

• From the date retention money is first withheld
• At the prescribed rate (not commercial bank deposit rates)
• Compounding annually unless the contract specifies otherwise
• When retention money is released

Many principals overlook the interest obligation, but it's not optional. The interest belongs to the payee and must be calculated and paid when retention is released.

Common Construction Retention Money Mistakes

From project management experience across $750M worth of New Zealand construction projects, these are the most common retention money compliance failures:

1. Using Retention as Working Capital

Some principals treat withheld retention as available funds for project expenses. This breaches the trust obligation and can lead to serious legal consequences if the principal becomes insolvent.

2. Delayed Release After Defects Period

Retention should be released promptly after the defects liability period expires (assuming no defects). Holding retention beyond this point without justification can result in penalty interest claims.

3. Inadequate Record Keeping

Principals must maintain clear records of retention money held for each contract. Poor record keeping makes it difficult to calculate interest and can create disputes about release timing.

4. Set-off Against Other Claims

Retention money cannot be used to set-off unrelated claims unless the contract specifically permits this and the claim is properly established through the contract process.

Retention Money in Subcontract Chains

Construction retention money obligations become complex in subcontract chains. The main contractor typically:

• Withholds retention from subcontractors at the same rate they're paying to the principal
• Holds subcontractor retention on trust with the same CCA obligations
• Releases subcontractor retention when they receive their retention from the principal

This creates a cascade of trust relationships. Each party in the chain has obligations to those below them, regardless of whether they've received their own retention release.

Back-to-Back Retention Provisions

Many head contractors include "back-to-back" retention clauses in subcontracts, stating that subcontractor retention will only be released when the head contractor receives theirs from the principal. While commercially understandable, these provisions don't alter the trust obligations under the CCA.

Enforcement and Remedies for Retention Breaches

When principals fail to comply with construction retention money obligations, payees have several enforcement options:

Adjudication Under the CCA

Disputes about retention money can be referred to adjudication under the Construction Contracts Act. This includes disputes about:

• Failure to hold retention in a separate account
• Refusal to pay interest on retention
• Delayed release of retention after the defects period
• Set-off of retention against disputed claims

Penalty Interest Claims

If retention is not released when due, the payee can claim penalty interest at the rate prescribed under the CCA. This is typically higher than the standard interest rate and is designed to discourage late payment.

Trust Law Remedies

Since retention is held on trust, payees may have additional remedies under trust law if the principal breaches their trust obligations. This can include personal liability for trustees who misuse trust funds.

Best Practice Construction Retention Money Management

To ensure compliance with construction retention money obligations in New Zealand:

1. Establish separate trust accounts before withholding any retention money
2. Maintain detailed records of retention withheld, interest calculations, and release dates for each contract
3. Set up automated systems to track defects liability periods and trigger retention releases
4. Calculate interest regularly using the correct prescribed rate and compounding method
5. Review contract provisions to ensure retention rates and release mechanisms are clearly defined
6. Train project teams on CCA obligations and the trust nature of retention money

Construction retention money compliance is about more than avoiding disputes. It maintains the cash flow relationships that keep projects moving and protects all parties' interests.