How do I request the release of retention?

The first part is often released on practical completion. The rest often follows at the end of the rectification (defects) period, or on the certificate that closes it. Your request has to cite the event your subcontract actually uses. Send one letter. Set out the retention held to date, cycle by cycle, and the trigger event with its date or certificate. Then state the sum it releases and the cycle it should be paid in, and attach the certificate. Under most subcontracts the release is part of the ordinary payment cycle. So it should appear in your next application, and the Payment Notice and Pay Less Notice rules apply to it as to any other payment. To keep holding it, your main contractor must send a Pay Less Notice under section 111 of the Housing Grants, Construction and Regeneration Act 1996. That is the notice it must send, in time, if it plans to pay you less than the sum due. It must show how it worked out the lower figure. If the trigger is a certificate that has not been issued, ask for the certificate instead. That is a different letter, to a different person. Keep a record of the retention deducted in each cycle, because the first thing your main contractor will dispute is the amount.