What are the main differences between JCT 2016 and JCT 2024 for subcontractors? The JCT 2024 suite reduces the main contractor’s Extension of Time assessment window from 16 weeks to 10 weeks, expands Relevant Events to include asbestos discovery, contaminated land, and unexploded ordnance (UXO), and updates termination grounds for corporate insolvency.
If you are a UK trade subcontractor, the ground beneath your feet has shifted. Main contractors are actively transitioning from the older JCT 2016 editions to the updated JCT 2024 Sub-Contract Conditions.
While much of the core structure remains familiar, the 2024 edition introduces crucial procedural timeline shifts and expanded risk allocations. Below, I break down the three most important changes in the JCT 2024 suite, how they affect your site operations, and how to protect your cash flow before signing.
1. The 10-Week EOT Decision Window (Down from 16 Weeks)
Technical Authority: JCT DBSub / SBCSub 2024 Clause 2.28 (Extension of Time Assessment).
Plain English Translation: Under the older JCT 2016 rules, when you submitted an Extension of Time request with particulars, the main contractor had a comfortable 16-week period to assess and respond. JCT 2024 compresses this deadline to just 10 weeks from the date full particulars are provided.
Loss Aversion & Financial Risk: While a faster decision prevents contractors from sitting on delay claims for months, it is a double-edged sword. Because commercial managers face a tighter turnaround, they will immediately reject any delay notice that lacks comprehensive programme substantiation. If your initial notice is rejected, you risk accumulating Liquidated and Ascertained Damages (LADs), triggering severe revenue loss.
2. Expanded Relevant Events: New Statutory Site Protections
Technical Authority: JCT DBSub / SBCSub 2024 Clause 2.27 (Relevant Events).
Plain English Translation: JCT 2024 modernises unforeseen site risks by explicitly adding new Relevant Events that entitle you to an Extension of Time without relying on complex common-law arguments. These include:
- Asbestos Discovery: Work stoppages resulting from unexpected asbestos on site.
- Contaminated Land: Discovering hazardous soil conditions or pollutants during excavation.
- Unexploded Ordnance (UXO): Delays caused by unearthing wartime munitions or historical ordnance.
- Epidemics & Statutory Shifts: Delays arising from government health restrictions or post-contract legislative changes affecting labour supply.
3. Collaborative Working & Insolvency Provisions
Technical Authority: JCT 2024 Collaborative Working Clause and Clause 8 (Termination for Insolvency).
Plain English Translation: Good-faith collaboration and early warning notices are now formally integrated into the standard contract body rather than optional supplemental provisions. In addition, termination clauses have been updated to align with modern corporate restructuring processes under UK insolvency law.
Loss Aversion & Financial Risk: If a main contractor enters formal administration, updated insolvency definitions determine whether you can lawfully terminate and recover demobilisation costs. Ensuring your draft does not contain bespoke amendments watering down these protections is vital to defending your business.
Frequently Asked Questions About JCT 2024 Changes
How long does a contractor have to assess an EOT under JCT 2024?
Under standard unamended JCT 2024 subcontract conditions, the main contractor has 10 weeks from the date of receiving full delay particulars to notify the subcontractor of their Extension of Time decision (reduced from 16 weeks in JCT 2016).
Are unexploded bombs covered as a delay event in JCT 2024?
Yes. Unexploded Ordnance (UXO) discovery is now explicitly listed as a standard Relevant Event in the JCT 2024 suite, entitling the trade contractor to claim an Extension of Time for site shutdowns.
Does JCT 2024 replace existing JCT 2016 subcontracts automatically?
No. Existing contracts signed under the JCT 2016 suite remain governed by 2016 terms throughout their lifecycle. JCT 2024 terms only apply when explicitly specified in new project agreements.