Every tier-one consultancy hits the same wall on Gulf mega-projects: the detailed-design mountain. Hundreds of wet-utility sheets — water, sewer, drainage, irrigation — all due at Stage 4 IFC, all needing co-ordination against six other disciplines, all on a programme that was optimistic when it was written. The rational answer is specialist subconsultancy. The risk is appointing the wrong one and discovering it at the worst possible moment: in front of the client's reviewer.
We sit on the subconsultant side of this table. Here is the checklist we would use if we were on yours.
1 · Demand CDE discipline, not CDE promises
Anyone can say they "work in BIM 360". Ask instead:
- Show us a transmittal history from a previous project — issue, revision, status codes, response cycles.
- Who in your team administers your side of the workflow, and what happens when a model is rejected at gate review?
- Will you follow our EIR and BEP as written, and what's your process when those documents are silent?
A team that answers in specifics has lived inside a CDE. A team that answers in product names has watched a demo.
2 · Make clash ownership explicit
The single most expensive ambiguity in subconsulted design: who owns the clash? Resolve it in the appointment:
- Subconsultant resolves internal clashes (their utilities against their utilities) before every issue — no exceptions.
- Cross-discipline clashes are raised by the subconsultant with a proposed resolution, decided in the co-ordination meeting, actioned within the agreed cycle.
- The clash report format, tool (Navisworks or model checker), tolerance matrix and run frequency are written into the scope — not improvised after mobilisation.
Red flag: a subconsultant whose fee assumes one clash-resolution cycle per package. Real packages take three. If they haven't priced it, you will pay for it — in variations or in delay.
3 · Inspect drawing control, not drawing samples
Sample sheets show drafting cosmetics. Control systems show whether sheet 214 of 380 will be right. Ask for:
- The drawing register from a live package — numbering, revisions, status, planned vs actual issue dates
- Their checking chain: drafter → checker → approver, with named people and evidence the checker is not the drafter
- CAD standards compliance: layers, title blocks, xref discipline matching your standard, not theirs
- How design changes propagate: when the model changes, what forces every affected sheet to update?
4 · Verify the engineering behind the drafting
IFC production outfits that are pure drafting shops produce beautiful sheets of wrong design. The difference shows in one question: "Walk us through how your network sizing responds if the rainfall criteria change at 60% design." A real engineering team explains the model-to-drawing pipeline — hydraulic model, sizing calcs, drawing extraction — and the change takes days. A drafting shop redraws by hand and the change takes weeks, with errors. On KSA work, also confirm the team has actually derived Saudi rainfall design criteria and faced a MOMRAH review, not just inherited someone else's numbers.
5 · Contract mechanics that protect you
- Back-to-back terms with your appointment, including the bits subconsultants dislike: programme float ownership, fitness-for-purpose alignment, IP assignment on models
- Named key personnel with substitution requiring consent — the principal who signed the proposal does the work, not a bench you have not met
- Deliverable-linked payments, not time-based — paid at accepted milestones
- PI insurance sighted, current, and adequate for the package value
- NDA from day zero — standard on every mega-project; instant disqualifier if resisted
The 10-minute test
If you take one thing: in the first meeting, put a marked-up GA on the screen and ask them to talk through how it becomes thirty IFC sheets. Teams that have done it narrate the system — model structure, sheet extraction, checking gates, transmittal. Teams that haven't talk about software licences and headcount. Ten minutes; near-perfect signal.
If you would rather just see the system working: our wet utilities and IFC delivery scope covers exactly this, and the project record shows it running on Aramco Stadium and Jeddah Central. Send the package outline — a principal replies with a scope, a fee and their own name on it within two business days.