Float, Concurrent Weather, and a Time Extension Request
The baseline CPM network for a structural package has two paths. Path 1: A (5 d) → B (10 d) → D (7 d) → F (4 d). Path 2: A (5 d) → C (8 d) → E (6 d) → F (4 d). Notice to proceed is Day 1 and all durations are in workdays. In week 2 the owner's elevator submittal review holds activity D for 6 workdays. Separately, 4 workdays of rain stop work on activity C. The contract is time-is-of-the-essence, grants weather time only to the extent it delays the critical path, contains no float-sharing language, and sets liquidated damages at $2,500 per day. For LD purposes, treat one workday as one calendar day. The contractor requests a 10-day extension and submits an $18,000 acceleration claim for activity C.
1. Compute project duration and the total float of activities C and D.
Read the worked answer
Path 1: 5 + 10 + 7 + 4 = 26 workdays Path 2: 5 + 8 + 6 + 4 = 23 workdays
Project duration = 26 workdays; planned completion is Day 26 on the controlling Path 1.
Float:
- D sits on Path 1 and lies on the controlling chain between B and F, so TF = 0. D is critical.
- C sits on Path 2, which finishes 3 days before the project, so TF = 3 (as does E).
Note that C's float is not "the contractor's" to spend; with no float-sharing clause, float is a project property. But the float amount still governs whether a delay on C reaches the completion date.
2. How many days of time extension is the contractor entitled to? Show the day-by-day effect of each delay.
Read the worked answer
Owner delay on D (6 workdays): D has zero float, so the full 6 days pass through to completion.
- New project duration = 26 + 6 = 32 workdays. Revised contract completion = Day 32.
Rain on C (4 workdays): C has 3 days of float.
- Path 2 originally 23 → becomes 23 + 4 = 27.
- Against the revised critical path of 32, Path 2 is still 5 days short of controlling. The 4 days consumed the 3 days of float and produced no extension.
Entitlement: 6 days, not 10. Neither delay extends the other, so this is not a true concurrency question; it is straightforward float consumption on the non-critical path.
Extended completion date: Day 32.
3. If the job finishes on Day 35, what is the LD exposure, and is the $18,000 acceleration cost on C recoverable?
Read the worked answer
LDs: Day 35 − Day 32 = 3 compensable-delay-free days over. At $2,500/day → $7,500.
Acceleration on C: not recoverable.
- C carries 3 days of float and is not on the controlling path. Compressing C saves zero days on the project - the money buys nothing, so it cannot be a cost of the owner's delay.
- Weather is non-compensable under this contract, so there is no compensable delay on C to accelerate against.
- There was no owner order to accelerate, so no constructive acceleration. A unilateral decision to speed up in the face of float is a contractor business decision.
Owner scheduler's response: Deny the acceleration claim, grant 6 days, and advise that if the contractor genuinely needs to recover time, the only useful target is Path 1 - resequencing F, splitting B, or overlapping D with B - because compressing C cannot move the completion date at all.