Delays in Construction: Types, Causes and Records

Almost every project runs late somewhere. What decides who pays for it is usually the quality of the records kept at the time.

Types of delays in construction

The exact definitions and remedies come from your contract. Standard forms differ on notice periods, what counts as a relevant event, and how concurrent delay is treated.

Common causes of construction delays

• Design and information: incomplete drawings, late RFI responses, slow submittal approvals, design changes.
• Owner issues: late site access, late decisions, late payment, scope changes.
• Contractor issues: poor planning, under-resourcing, subcontractor failure, late procurement, rework from defects.
• Site conditions: unforeseen ground conditions, existing services, contamination.
• External: weather, permits and inspections, supply chain disruption, labour availability.
• Coordination: clashes between trades, especially in MEP-dense areas, discovered late on site.

How delays are analysed

When a delay is disputed, a planner or delay expert analyses the schedule to show what caused the late finish and by how much. Common methods are:

• As-planned vs as-built: compares the baseline schedule with what actually happened. Simple, but weak at showing cause.
• Impacted as-planned: adds delay events into the baseline programme to show their theoretical effect.
• Time impact analysis (TIA): inserts each delay event into the updated schedule at the time it occurred. Often used prospectively to support an extension of time request.
• Windows analysis: divides the project into time periods and analyses the critical path in each.
• Collapsed as-built (but-for): removes delay events from the as-built schedule to show when the work would have finished without them.

Every method depends on knowing what actually happened on site, and when. Guidance such as the Society of Construction Law Delay and Disruption Protocol puts strong emphasis on good contemporaneous records for this reason.

How to manage delays: a practical process

1. Keep the schedule updated with actual progress at a regular interval, so the critical path is current.
2. Record the site as it is. Daily reports, dated photos, 360° walks or scans of the same areas at regular intervals.
3. Give notice on time. Most contracts set a notice period for delay events. Late notice can lose an otherwise valid claim.
4. Log the event and its effect: what happened, when, which activities it affected, and the evidence.
5. Mitigate. Re-sequence, add resources or work around where reasonable, and record what you did.
6. Raise it in the OAC meeting and get the decision or action minuted.
7. Prepare the extension of time request with the schedule analysis and the supporting records.

Common mistakes

• Building the story afterwards. Records gathered months later from memory are easy to challenge.
• Photos without dates or locations. They prove something happened, but not where or when.
• Missing notice deadlines.
• A schedule that isn't updated, so nobody can show which activities were critical at the time.

Where SpatialSense fits

SpatialSense doesn't analyse schedules or calculate extensions of time. Where it helps is the record those analyses depend on. Each 360° walk and scan is timestamped when it's added to a project, and Trace walks are GPS-tagged, so a regular capture routine builds a dated visual record of the site as it actually was.

• Show the state of an area on a given date, for example when access was handed over or when a trade finished.
• Compare two dates side by side to show what did, and didn't, progress in between.
• Pin issues at their location, such as an area blocked by another trade, with an owner and a status.

Frequently asked questions