Gantt Chart Presentation
Last reviewed 9 September 20262,204 words10 min read
Making a bar chart that a reviewer can read in ninety seconds and cannot misread in twenty minutes
🟩 In one line: A printed Gantt is a legal document the moment it leaves the office — data date line, baseline bars, revision, filter and page numbers on every sheet; grouped by WBS, sorted by early start, critical in one colour, and nothing on it that the schedule does not actually contain.
👤 Who this is for: Junior planners printing submissions; anyone who has been handed a 140-page roll and asked "where's the problem?" Prerequisites: P6-layouts-and-filters, P6-baselines-assign-and-maintain.
First, let's be honest about why this page exists
The Engineer's first impression of your update is the printed Gantt, and most of them are unreadable: 2,800 activities on A3 at a two-year timescale, relationship lines like spaghetti, no data date line, no baseline bars, and a footer that says "Layout 1". The reviewer cannot find the critical path, so they assume you are hiding it.
Presentation is not decoration. The bar chart has to show the same facts the narrative states — DD, baseline, forecast, critical path, float — and it has to do so without a manual.
🟨 The standard — what "good" looks like
| Source | What it says (paraphrased) | Use it for |
|---|---|---|
| FIDIC 1999 Cl 8.3 / 2017 Cl 8.3 | Programme in the form stated in the Specification, showing order, timing and critical path (2017) (check against your copy) | The Gantt is a contract document |
| NEC3 / NEC4 Cl 31.2 | Programme shows dates, order, timing, float, time risk allowances, health-and-safety requirements — legible enough for acceptance under Cl 31.3 | Everything Cl 31.2 lists must be visible or referenced |
| PMI Practice Standard for Scheduling, 3rd ed. | Presentation of the schedule model as bar charts, with baseline comparison (check against your copy) | Terminology |
| GAO Schedule Assessment Guide, Best Practice 3 | Critical path identified and traceable | Critical in one colour, filterable |
| DCMA 14-Point, item 12 (Critical Path Test) | Critical path continuous and identifiable | The reviewer will test it from your print |
| Client specifications (typical Gulf) | Bar chart at stated levels; baseline and current bars; DD line; float column; critical highlighted; A3/A1 as specified | The format checklist |
| Hub convention | Six layouts (00 Submission where specified); submissions sorted Early Start within WBS; three bar sets (current, Project baseline, previous update); LOE and WBS Summary excluded on float/review layouts; footer with DD, baseline, revision | Your defaults |
🟢 Rule: every printed page carries data date, baseline name, update number, filter name and "page x of y"; if any of the five is missing the print is not a submission.
How it actually works
1. One submission layout, fixed at baseline. Layout 00 Submission (or 01 Update where the spec is silent), saved project-level and as .plf in the archive. Settings:
| Element | Setting (check against your P6 version) |
|---|---|
| Group | WBS to Level 3 (or the spec's level), then Area/Level codes for Level 3 prints; summary bars on for WBS bands |
| Sort | Early Start, then Activity ID within each band |
| Filter | Not complete OR finished since previous DD; LOE and WBS Summary excluded on the float pages, included on the full print |
| Columns | Activity ID, Name, OD, RD, Start, Finish, Total Float, Physical %, BL Project Start, BL Project Finish, Variance — BL Project Finish Date (check against your copy), Subcontractor |
| Bars | Bar 1 Remaining (current) — blue, critical red by filter Longest Path; Bar 2 Actual — solid; Bar 3 Project baseline — narrow grey below; Bar 4 previous update (Primary User baseline) — narrow dashed, on the review print only |
| Milestones | Diamonds; contractual milestones labelled with date; FOoB shown with the constraint marker |
| Data date | Vertical line, labelled with date; Bars → Options → Data Date line on |
| Relationship lines | Off on prints above 300 activities; on for the critical-path print |
| Timescale | Month/week for the two years round the DD; year/month beyond; no timescale finer than the print can show |
| Font / row height | Smallest legible on the sheet size — A3 portrait ~55 rows/page; A1 ~150 |
| Progress line | Off; the DD line and Physical % column do the job without argument about spotlight methods |
2. Header and footer. Page Setup → Header/Footer: project name and contract number; "Update NN — Data Date DD-MMM-YY"; "Baseline: BLn-Accepted-DD ddMMMyy-Revn"; layout/filter name; revision and issue date; legend box (bar colours, milestone symbols); page x of y. Same footer on every layout.
3. Three prints, not one.
| Purpose | Filter | Pages | |
|---|---|---|---|
| Full programme | Contractual record | All (LOE/WBS Summary included) | As many as it takes |
| Critical and near-critical | Reviewer's first read | Longest Path OR Total Float ≤ near-critical threshold; grouped by Float Path (layout 04b) | 2–6 |
| Milestones and Level 1 summary | Executive read | Milestone Type ≠ null OR Report Level = L1 | 1–2 |
The reviewer starts with the second; give it to them first.
4. Colours and symbols, once and for all. Red = longest path only. Yellow/amber = near-critical (TF within threshold). Blue = current remaining. Grey = baseline. Black = actual. Purple = LOE. No other colours. Diamonds for milestones; filled black when achieved. Do not colour by subcontractor on a submission — do that on the internal coordination print.
5. Scale honesty. Do not compress the timescale to make a slip look small, and do not hide a section by collapsing its WBS band on the submission. If the specification limits page count, collapse to Level 2 with the Level 3 print in an appendix and say so on the transmittal.
6. Electronic prints. PDF from P6 (Print → PDF), one file per layout, bookmarked by WBS band where the PDF driver allows; file name matches the XER convention with the layout suffix (e.g. Project_Upd14_DD25Oct_v01_L00-Submission.pdf). A screenshot pasted into PowerPoint is not a submission.
🟥 Where people go wrong
- No data date line. The reviewer cannot tell planned from actual and reads a half-done bar as a forecast. DD line on, labelled, every layout.
- Baseline bars missing. Slippage becomes invisible and the Variance column is the only evidence. Project baseline bar under every activity on every submission print.
- Relationship lines on a 2,000-activity print. Nothing is legible and the critical path is lost. Lines only on the critical-path print, where the chain is short enough to follow.
- Sorted by Activity ID. The bars form a random staircase and the sequence disappears. Early Start within WBS, always, unless the specification says otherwise.
- "Critical" coloured by Total Float ≤ 0 instead of Longest Path. With multiple calendars and constraints the two differ, and the red bars stop at a constrained milestone mid-programme. Longest Path drives the colour; float is a column.
- Footer says "Layout 1" and nothing else. Two prints from different months are indistinguishable in the claim bundle. Update number, DD, baseline, filter, page numbers.
- Timescale tuned per print. The March print at one scale, April at another; comparing them by eye is impossible. Fix the timescale settings in the layout and leave them.
⚖️ When you're challenged
"I can't see the critical path on this." It's the second print in the pack — 84 activities, red, grouped by float path with the chain ID sequence listed in the narrative. The full print is the record; the critical print is the read.
"Why are some bars red in the middle of the programme and not at the end?" They shouldn't be, and on this print they aren't — red is Longest Path only. If you're looking at the internal coordination print, that one colours by float, and constrained interface milestones can break the chain visually. The submission uses Longest Path.
"Just send me a picture of the schedule." I'll send the milestone and Level 1 summary — one page, DD line, baseline bars, footer with the update number. A cropped screenshot without those would be a different document from the one we submitted, and I'd rather not create it.
📄 Related pages
- P6 Layouts and Filters — building and saving the six layouts
- P6 Multiple Float Paths — layout 04b behind the critical print
- Critical path vs longest path — why red means Longest Path
- P6 Baselines: Assign and Maintain — the baseline bars
- Schedule Narrative — the ID sequence the critical print must match
- Monthly Progress Report — where the prints sit in the pack
✏️ Worked example — Sharjah mid-rise, Update 09 submission pack
| Layout | Filter | Pages (A3) | Header/footer | |
|---|---|---|---|---|
| P1 Full programme | 00 Submission | All, LOE incl. | 38 | "Upd09 — DD 25-Jun — BL0-Accepted-DD 25Sep-Rev0 — Filter: All — p x/38" |
| P2 Critical & near-critical | 04b Float Paths | Float Path ≤ 5, TF ≤ 15 wd | 4 | Same, "Filter: Float Paths 1–5" |
| P3 Milestones & L1 | 00 Submission (Report Level) | Milestone Type ≠ null OR Report Level = L1 | 1 | Same, "Filter: Milestones & L1" |
Bar legend on every page: Blue remaining · Red longest path · Amber TF ≤ 15 · Black actual · Grey BL0 · Purple LOE · ◇ milestone · ◆ achieved · ▲ FOoB constraint.
Columns on P2: ID · Name · RD · Start · Finish · TF · Float Path · Float Path Order · BL0 Finish · Variance · Subcontractor. First row of P2, path 1: STR-L11-SLB-POUR-B — RD 1 — TF 0 — path 1 order 1 — BL0 finish 18-Jun — variance −6.
Transmittal note: "Prints P1–P3 generated from project-level layouts 00 and 04b saved 25-Jun, .plf files archived; timescale month/week Jan Y1–Dec Y2, year/month thereafter; relationship lines shown on P2 only."
📖 References
- FIDIC Conditions of Contract for Construction 1999 and 2017, Cl 8.3 (check the edition in your contract)
- NEC3 / NEC4 ECC, Cl 31.2, 31.3 (check the edition in your contract)
- PMI, Practice Standard for Scheduling, 3rd ed. (check against your copy)
- GAO, Schedule Assessment Guide, GAO-16-89G, Best Practice 3; DCMA 14-Point Schedule Assessment, item 12
- Oracle Primavera P6 Professional User Guide — Bars; Page Setup; Print Preview; Layouts (check against your P6 version)
From the field
Experience from working planners. Unreviewed — read it as experience, not guidance.
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