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Issues white paper 2026

BIM Clash Report 2026

Which clashes HOOK’s BIM coordination finds most, how they happen, why, and how they get fixed. Based on 6,493 tagged issues from 18 projects.

Live figures from HOOK’s issue log, updated 10 Nov 2026, 01:10 (Bangkok time).

The most common clash behavior was Hard Clash: 38.6% of the clashes we tagged.

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  • Structure × MEP
  • Architecture × MEP
  • Structure × Architecture
  • MEP × MEP
  • Structure
  • Architecture
  • Discipline not recorded

Hover or tap a floor to see its clashes. Click a dot to see that clash up close. Drag to turn, right-drag or two fingers to move, scroll or pinch to zoom.

Ground floor & mezzanine

2,628 issues
  • Structure × MEP602
  • MEP × MEP488
  • Architecture × MEP463
  • Structure × Architecture450
  • Architecture388
  • Structure231
  • Discipline not recorded6
Most frequent pairs
  • Beam × Pipe · 193
  • Ceiling × Pipe · 106
  • Foundation × Pipe · 105

164 issues had no floor recorded and are not drawn.

Each dot stands for about 50 clashes from HOOK’s issue log, drawn on the floor they were recorded on, where the two elements involved meet, and coloured by the disciplines involved. The building is illustrative.

  • 7,436

    issues reviewed

    6,493 tagged by type, cause and fix

  • 18

    projects

    Condominium, Factory building, Hospital and 3 more

  • 38.6%

    most common clash behavior: Hard Clash

  • 64.7%

    most common root cause: Lack of Coordination

Shares on this page are of the 6,493 tagged issues.

Summary

Five things we found

What stands out when every project’s issues are read together. We kept only findings that repeat project by project, not just in the totals.

  1. Ground floors have the most issues

    About 3 times as many issues per floor as the floors above, in every project we could compare. It is where foundations, pipes and the cables coming into the building meet.

  2. Most issues aren’t collisions

    Fewer than half are elements actually hitting each other. The rest are things like wrong levels, misalignment, exposed services or too little space.

  3. Coordination is the main cause

    About 7 in 10 come from design teams not coordinating, and about 1 in 4 from late design information or models not updated to the latest drawings.

  4. Building services are involved most

    6 in 10 issues involve services such as pipes, ducts or cables. Pipe against beam is the most common pair, and rerouting the pipe is the most common fix.

  5. Issues waiting on a decision stay open more often

    About 4 in 10 issues waiting on a decision from the designer, the owner or a consultant are still open, against 3 in 10 for the rest. This holds in 9 of 11 projects.

Based on 7,346 issues in 18 projects as of 24 October 2026. This section is not updated automatically.

01

What collides

The element pairs that clash most

Beam × Pipe topped the list with 514 clashes, 7.9% of all tagged issues.

Pick a pair to see it in 3D, then switch between the clash and the fix.

  • Beam
  • Pipe
  • Clash zone
  • After the fix

How Beam × Pipe clashes

  1. 01Hard Clash77.4%Two solid elements take up the same space, such as a pipe running through a beam.398 issues
  2. 02Penetration11.1%A service passes through a wall, slab or beam where no opening was planned.57 issues
  3. 03Clearance Violation9.3%The gap needed for access, maintenance or insulation is missing.48 issues

Share of this pair’s 514 clashes. One clash can carry more than one behavior.

02

How they collide

Clash behaviors

Hard Clash led the behaviors at 38.6%. A behavior describes what two elements do to each other, such as a pipe running through a beam.

Behavior

  1. 01Hard Clash38.6%Two solid elements take up the same space, such as a pipe running through a beam.2,505 issues
  2. 02Misalignment16.4%Elements that should line up across disciplines are offset from each other.1,065 issues
  3. 03Wrong Elevation12.6%An element sits at the wrong height for the levels and elements around it.821 issues
  4. 04Exposed11.4%An element that should be hidden shows below a ceiling or outside a finish.742 issues
  5. 05Clearance Violation10.1%The gap needed for access, maintenance or insulation is missing.653 issues
  6. 06Location Conflict9.7%An element is placed where another discipline needs the space.630 issues
  7. 07Size Conflict4.9%An element is too big for the space or opening it has to fit into.315 issues
  8. 08Missing Opening4.3%A service needs an opening, sleeve or shaft that is not in the model.281 issues

Elements found in clashes

How often each element shows up in a tagged clash, on either side.

  1. 01Pipe35%2,275 issues
  2. 02Beam23.3%1,516 issues
  3. 03Slab17.3%1,124 issues
  4. 04Wall14.6%949 issues
  5. 05Ceiling12.9%840 issues
  6. 06Equipment10.8%702 issues
  7. 07Duct8.5%555 issues
  8. 08Door / Window7.7%503 issues
03

Why

Root causes

The root cause is why a clash reached the model in the first place. It shows which step of the process needs to change.

64.7%

of the clashes we tagged traced back to Lack of Coordination.

Root cause

  1. 01Lack of Coordination64.7%Disciplines modelled the same zone without agreeing who goes where.4,198 issues
  2. 02Model Not Linked / Outdated10.1%A team worked against a missing or old copy of another discipline’s model.658 issues
  3. 03Late Design Input7.1%Design information arrived after the model in that area was built.464 issues
  4. 04Design Change Not Updated7%The design changed, but the model did not follow.455 issues
  5. 05Incorrect LOD5.9%An element was modelled at too low a level of detail to check properly.382 issues
  6. 06Assumption Conflict1.9%Two teams filled the same gap in the design with different assumptions.121 issues
  7. 07Wrong Discipline Reference0.4%A team referenced the wrong discipline’s model or drawing.27 issues
04

How we fix them

Solutions

The most common fix was MEP to reroute, used on 32.8% of tagged issues.

Solution type

  1. 01MEP to reroute32.8%2,127 issues
  2. 02ST to confirm structure23.1%1,498 issues
  3. 03AR to revise model22.1%1,438 issues
  4. 04Change Elevation15.5%1,006 issues
  5. 05Shift Element13.4%871 issues
  6. 06Reroute (Duct / Pipe / Tray)11.9%774 issues
  7. 07BIM to coordinate & recheck9%582 issues
  8. 08Resize Element7.4%480 issues

From cause to fix

The root cause and solution pairs that came up most often.

  1. 01Lack of Coordination fixed by MEP to reroute26.8%1,743 issues
  2. 02Lack of Coordination fixed by AR to revise model14.2%925 issues
  3. 03Lack of Coordination fixed by ST to confirm structure14.1%914 issues
  4. 04Lack of Coordination fixed by Change Elevation11.3%735 issues
  5. 05Lack of Coordination fixed by Shift Element10.8%699 issues
  6. 06Lack of Coordination fixed by Reroute (Duct / Pipe / Tray)10.8%698 issues
  7. 07Lack of Coordination fixed by Resize Element5.4%353 issues
  8. 08Lack of Coordination fixed by Revise Layout4.7%307 issues
05

Return on coordination

What fixing these clashes in the model saved

Had the 4,293 closed clashes counted here reached site, fixing them there would have cost about 40.6 million baht: at least 27.4 million baht, at most 165.2 million baht. That is before the cost of BIM coordination itself.

Worked out one event at a time, from published research and official Thai prices. Each line names its source. Money is in baht, excluding VAT and the contractor’s overhead and profit.

  • Beam
  • Duct
  • Clash zone
  • After the fix

The case in 3D: the duct against the beam, then after the fix.

Step 1

One clash, had it reached site

An 800 × 600 mm duct runs into a beam above a false ceiling, with a cable tray beside it. Found on site, the duct is remade smaller to pass under the beam and the ceiling is lowered, which takes 2 days of site work (Abbas, 2015, pp. 36–38).

Cost lineLowLikelyHigh
Site labourDuct taken down and refitted: 1.5 days of an air-conditioning technician (470–675 baht a day) with a helper (400 baht). Ceiling of 16 m² taken down and redone: 2 days of a gypsum installer (485–595 baht) with a helper. (Abbas, 2015, pp. 37–38; คณะกรรมการค่าจ้าง, 2566; คณะกรรมการค่าจ้าง, 2568)3,0753,4453,603
Materials6 gypsum boards, 9 mm, for 16 m² at 238 to 244 baht each; the low case reuses the old boards. The new duct takes the same weight of sheet as the old one. (สำนักงานนโยบายและยุทธศาสตร์การค้า, 2569)01,4281,464
RedesignAn architect, a mechanical and an electrical engineer agree the fix in 3 days: 3 person-days (9 in the high case) at 2,744–3,694 baht a day, the reference rate for an engineer with 5 years’ experience (10 in the high case). (Abbas, 2015, p. 37; ศูนย์ข้อมูลที่ปรึกษา สำนักงานบริหารหนี้สาธารณะ, 2567)8,2328,23233,247
Change administration8% of the direct cost, and at least 3 hours of an engineer. (RAIC, 2009, as cited in Bockstael & Issa, 2016, p. 240)1,0291,0291,385
One event12,33614,13439,699

Cross-check: the Comptroller General’s Department labour rates for the same ceiling and duct work come to 2,691–3,818 baht (กรมบัญชีกลาง, 2569), against 3,075–3,603 baht above.

Left out, to stay on the cautious side: rerouting the cable tray (the case gives no quantity for it), the contractor’s overhead and profit, VAT, and any delay to the programme.

Step 2

From one event to six kinds of fix

Each closed issue is placed by the solution its coordinator tagged. An issue tagged with several counts once, in its costliest kind. A kind’s event is the base event scaled by how much one issue of the matching trade cost, relative to building services, in a project where 932 issues were costed (Camer, 2024).

Only clashes that would really have reached site count (Chahrour et al., 2021): between 25% (Bockstael & Issa, 2016, p. 240) and 47% (Camer, 2024) of them. The likely case uses 47% for Critical, Regulation and Major issues and 25% for Minor ones, which is HOOK’s assumption between the two studies.

Kind of fixClosed issuesWould reach siteOne eventAvoided
Openings in structureAdd, move or enlarge a sleeve or an opening: 10.9× the base event, as structural steel against building services. The likely case is held at the low end.334139 Major or higher · 195 Minor114134,200 baht134,200 baht to 431,900 baht15.3 million baht11.2 million baht to 67.8 million baht
Architectural layoutRevise a layout or a zone: 2.8× the base event, as ceiling and panel work against building services.1,070453 Major or higher · 617 Minor36739,100 baht34,200 baht to 109,900 baht14.4 million baht9.1 million baht to 55.3 million baht
Reroute servicesReroute, raise, shift or offset a duct, pipe or tray: the base event itself.1,966781 Major or higher · 1,185 Minor66314,100 baht12,300 baht to 39,700 baht9.4 million baht6.1 million baht to 36.7 million baht
Resize or change a systemResize an element or change a system type: priced as the base event.16899 Major or higher · 69 Minor6414,100 baht12,300 baht to 39,700 baht901,500 baht518,100 baht to 3.1 million baht
Structure to confirmA structural engineer checks it: 1 day (3 in the high case) plus administration. No site work.347160 Major or higher · 187 Minor1223,773 baht3,773 baht to 12,500 baht460,100 baht327,300 baht to 2 million baht
Decisions and coordinationRefer, hold, accept with a condition, defer or recheck: 3 hours of administration. No site work.408155 Major or higher · 253 Minor1361,029 baht1,029 baht to 1,385 baht140,000 baht105,000 baht to 265,600 baht
All six4,2931,46640.6 million baht27.4 million baht to 165.2 million baht

Step 3

The total

Rework avoided
40.6 million bahtLikely; range 27.4 million baht to 165.2 million baht
Days of site work not lost
2,417 crew-daysLikely; range 1,769 to 3,326 crew-days · 2 crew-days for each event that is torn out and redone (Abbas, 2015, p. 38)
Of the construction value
0.23%Likely; range 0.15% to 0.92% · 715,450 m² in 18 projects × the construction cost per m² of each building type (มูลนิธิประเมินค่า-นายหน้าแห่งประเทศไทย, 2569). Across 98 projects, rework averaged 0.39% of contract value (Love et al., 2018).

  • Not counted: 2,211 issues still open or in progress, and 932 closed without a solution tag.

  • These are the costs avoided, before the cost of BIM coordination itself.

  • The figures add up every project in the log. None is shown for a single project.

References

  • Abbas, Y. G. (2015). Modeling the cost of clashes in construction projects using building information modeling [Master’s thesis, American University of Beirut]. AUB ScholarWorks. https://scholarworks.aub.edu.lb/bitstreams/dc59f9d0-964b-479a-9dbb-d44498e2717f/download
  • Bockstael, D., & Issa, M. H. (2016). A methodology for contractor clash detection using building information modelling on commercial construction projects. Journal of Information Technology in Construction, 21, 233–249. https://www.itcon.org/2016/16
  • Camer, R. (2024, November 4). The true value of clash detection: A detailed return on investment (ROI) case study. Design-Build Institute of America. https://dbia.org/blog/the-true-value-of-clash-detection
  • Chahrour, R., Hafeez, M. A., Ahmad, A. M., Sulieman, H. I., Dawood, H., Rodriguez-Trejo, S., Kassem, M., Naji, K. K., & Dawood, N. (2021). Cost-benefit analysis of BIM-enabled design clash detection and resolution. Construction Management and Economics, 39(1), 55–72. https://doi.org/10.1080/01446193.2020.1802768
  • Love, P. E. D., Smith, J., Ackermann, F., Irani, Z., & Teo, P. (2018). The costs of rework: Insights from construction and opportunities for learning. Production Planning & Control, 29(13), 1082–1095. https://doi.org/10.1080/09537287.2018.1513177
  • กรมบัญชีกลาง. (2569, 26 มิถุนายน). บัญชีค่าแรงงาน/ดำเนินการสำหรับถอดแบบคำนวณราคากลางงานก่อสร้าง [Labour and operation rates for estimating reference prices of construction work] (Attachment to Comptroller General’s Department letter กค 0433.2/ว 480) [Copy republished by Yotathai]. https://www.yotathai.com/passadu/w480
  • คณะกรรมการค่าจ้าง. (2566, 19 ธันวาคม). ประกาศคณะกรรมการค่าจ้าง เรื่อง อัตราค่าจ้างตามมาตรฐานฝีมือ (ฉบับที่ 13) [Wage Committee notification on wage rates by skill standard (No. 13)]. ราชกิจจานุเบกษา, 140(ตอนพิเศษ 318 ง), 53–64. https://ratchakitcha.soc.go.th/documents/14268.pdf
  • คณะกรรมการค่าจ้าง. (2568, 1 กรกฎาคม). ประกาศคณะกรรมการค่าจ้าง เรื่อง อัตราค่าจ้างขั้นต่ำ (ฉบับที่ 14) [Wage Committee notification on minimum wage rates (No. 14)]. ราชกิจจานุเบกษา, 142(ตอนพิเศษ 236 ง), 29–31. https://ratchakitcha.soc.go.th/documents/76681.pdf
  • มูลนิธิประเมินค่า-นายหน้าแห่งประเทศไทย. (2569). ราคาประเมินค่าก่อสร้างอาคาร พ.ศ. 2566–2569 [Building construction cost estimates, 2023–2026] [Table]. https://www.thaiappraisal.org/thai/value/value.php
  • ศูนย์ข้อมูลที่ปรึกษา สำนักงานบริหารหนี้สาธารณะ. (2567). หลักเกณฑ์ราคากลางการจ้างที่ปรึกษา [Reference prices for hiring consultants]. https://www.consultant.pdmo.go.th/docs/medium_price_new.pdf
  • สำนักงานนโยบายและยุทธศาสตร์การค้า. (2569). ราคาวัสดุก่อสร้างรายเดือนและรายปี: ส่วนกลาง (มกราคม–กันยายน 2569) [Monthly and yearly construction material prices: Bangkok region, January–September 2026] [Online database]. กระทรวงพาณิชย์. https://index.tpso.go.th/construction-material-prices/prices-building-materials/10

Disciplines involved

Structure appeared in more tagged clashes than any other discipline.

Discipline tags

  1. 01Structure54.8%3,557 issues
  2. 02Architecture49.1%3,187 issues
  3. 03Sanitary35.8%2,322 issues
  4. 04Mechanical21.2%1,378 issues
  5. 05Interior13.6%880 issues
  6. 06Landscape9.1%591 issues
  7. 07Electrical8.9%580 issues
  8. 08Fire Protection7.6%496 issues

Discipline flags on all 7,436 issues

Set on every issue in the log, tagged or not, so these counts use the larger sample.

Mechanical (ME)
4,138
Structure (ST)
3,590
Architecture (AR)
2,970
Landscape (LA)
588
Interior (ID)
543
Facade (FC)
143
Sanitary (SN)
53
Air conditioning (AC)
43
Electrical (EE)
35
Fire protection (FP)
31
Civil (CV)
1

How this report was made

Source

HOOK’s BIM coordination issue log (hook-tracker)

Issues logged

22 January 2026 to 9 November 2026

Data as of

10 Nov 2026, 01:10

Projects

18 (Condominium, Factory building, Hospital, Hotel, Mixed-use building and Residence)

Sample size

7,436 issues logged, 6,493 of them tagged (87.3%)

Status at cutoff

Closed 5,225 · Open 2,106 · In progress 105

Priority

Minor 4,473 · Major 2,874 · Regulation 60 · Critical 29

Every share on this page is a share of tagged issues. The coordination team adds the tags by hand, so coverage varies from project to project.

One issue can carry several tags, for example two elements and two behaviors, so the shares in a list can add up to more than 100%.

Project names, drawings and issue descriptions stay private. Only counts are published, grouped by project type.

The figures on this page come straight from the coordination issue log and refresh about every 10 minutes. Each year’s edition is kept as an archive with its figures fixed.

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