How do I calculate an extension of time?

Here is a worked example. The date for practical completion is 30 June 2027. The level 2 slab pour sits on the critical path and was due on 3 May. Revised drawings from the design team arrived on 17 May.

The crew poured on 19 May. That was two days after the drawings came, the time needed to set out again. The pour started 16 days late. It had no float, so the finish moves by 16 days.

Check for days that are yours. In this example the crew was ready and the crane was working, so all 16 days come from the late drawings. The example counts calendar days. Use the day count your contract uses.

Claim 16 days. The new date for practical completion is 16 July 2027. Attach the drawing transmittal, the programme before and after the event, and the site diary for 3 to 19 May.