What is the JCT payment timeline?

This is the timetable in section 4 of the JCT Standard Building Contract (SBC/Q 2016), the main contract. Each cycle starts from an Interim Valuation Date. The first is stated in the Contract Particulars. The rest fall on the same date each month, or the nearest Business Day, to the end of the job. So the whole timetable can go in the diary the day the contract is signed. Not later than 5 days after the due date, the Architect/Contract Administrator issues the Interim Certificate. It states the sum due and how it was worked out, and it is the Payment Notice for that cycle. Any Pay Less Notice must be given not later than 5 days before the final date. If an interim application was made by the Interim Valuation Date and no Payment Notice arrives, the application stands as the notice. Its sum becomes the notified sum. Two things catch people out. First, amended contracts often change the periods, usually by pushing the final date out and moving the Pay Less Notice window. Your JCT subcontract also sets its own periods. So build your diary from the signed contract and its amendments, not the standard form. Second, the due date runs from the Interim Valuation Date, not from when the application or certificate arrives. A late certificate does not move the due date or the final date. Count in calendar days, and treat the last day as the deadline.