Breaking the Works Into Subcontract Packages Without Leaving Gaps

How a main contractor divides a building into subcontract packages, where the scope gaps appear, and the sequence that closes them before anything is let.

A building does not divide neatly into trades. Every boundary between packages is a place where work can be left out, priced twice or built by nobody, and the cost of a gap is always higher than the cost of the work it contained. The sequence below defines the packages, tests the boundaries and lets the subcontracts with the interfaces already resolved.

Before stage one

You need a coordinated design, a procurement programme with lead times, a view on which packages you will self deliver and a measurement basis for each package. You also need to know how the main contract treats subcontracting, since some forms require consent to subcontract particular elements and most impose obligations that have to be passed down. Contract requirements and approval practices change over time, so read the current wording rather than relying on what the last project allowed.

• List the packages and mark each as self delivered, subcontracted or still undecided.
• Check the main contract for any consent requirement or restriction on subcontracting.
• Build a procurement programme working backwards from the site need date through fabrication and approval.
• Confirm the measurement basis each package will be priced on.
• Identify the packages where design responsibility will sit with the subcontractor.

Stage 1: Define the packages from the building, not from habit

Start with the building and ask what has to be procured as a unit. Some packages are obvious trades. Others are better defined by a physical zone, a system or a time window, such as all work in a plant room, or everything needed to make a floor watertight. Packaging by habit produces the same boundaries as the last project, and the gaps follow. Where two packages must interface, prefer giving both sides to one subcontractor even if that crosses a conventional trade line.

• Deliverable: A package list with a one line scope definition and a stated reason for each boundary.
• Owner: The commercial manager with the project manager.
• Approval gate: Every boundary has a reason that someone can state out loud.

Stage 2: Map the interfaces and name an owner for each

Walk the boundaries one by one. Who provides the opening the duct passes through, who fire stops it, who makes good the finish, who provides the fixing, who tests the result? List every interface and assign it to one package explicitly. Interfaces have a habit of appearing obvious in the office and contested on site, and the only cure is writing them down before either party has priced anything.

• Deliverable: An interface schedule naming the responsible package for every boundary item.
• Owner: The technical lead with input from the designer.
• Approval gate: No interface item is unassigned or assigned to two packages.

Stage 3: Write the scope documents package by package

Each package needs its own document set: the drawings that apply, the relevant specification sections, the measured quantities or the pricing basis, the interface schedule extract, the programme window, the site constraints and the attendances it will receive. Attendances matter more than they appear: scaffolding, power, water, hoisting, storage, welfare and waste removal are either provided by the main contractor or by the subcontractor, and leaving the position unstated guarantees a claim.

• Deliverable: A scope document for each package including a stated attendances position.
• Owner: The package surveyor.
• Approval gate: The attendances schedule is explicit for every package.

Stage 4: Select the subcontractors against the package, not generically

Assess each subcontractor for the specific package: has it done this system at this scale, who will supervise, what is its current workload, what is its financial position and does it carry the insurance the package requires? A subcontractor excellent at one package can be unsuitable for another in the same trade. Where the package carries design responsibility, confirm who the designer is and that professional cover exists for it.

• Deliverable: A selection record per package with capability, capacity, financial and insurance findings.
• Owner: The procurement lead.
• Approval gate: Every selected subcontractor has evidence against all four criteria for that package.

Stage 5: Tender each package on a common basis

Issue the same documents to every bidder, answer queries by addendum to all of them, require a single qualifications schedule and insist on a fully priced return. Then normalise the bids: price the qualifications, check the attendances assumptions and confirm that every bidder has allowed for the interface items assigned to that package. A subcontract bid that silently excludes an interface item is cheaper and will cost more.

• Deliverable: A normalised comparison for each package with every qualification valued.
• Owner: The package surveyor.
• Approval gate: Each bid is confirmed to include the interface items assigned to its package.

Stage 6: Let the subcontract with the terms aligned to the main contract

The subcontract has to carry the obligations the main contract imposes, including programme, quality regime, notice requirements, insurance, safety obligations and defects liability. It also has to be workable for a company of that size. Terms copied wholesale from a main contract into a small subcontract are often unenforceable in practice and always resented, which affects performance. This drafting has a legal dimension, so the standard subcontract wording should be settled with a licensed legal adviser once rather than negotiated afresh each time.

• Deliverable: An executed subcontract with aligned obligations and a clear payment mechanism.
• Owner: The commercial manager, with legal support on the standard terms.
• Approval gate: Every obligation the main contract imposes on the works in that package appears in the subcontract.

Stage 7: Mobilise the package and hold a pre start meeting

Before the subcontractor arrives, hold a meeting covering the programme window, the interfaces, the attendances, the quality regime and the inspection points, the safety requirements and the payment procedure. Record it and have both parties sign the record. Most subcontract disputes are about something that was clear to one party and never said to the other, and an hour at this point removes several weeks of argument later.

• Deliverable: A signed pre start record covering scope, interfaces, attendances, quality, safety and payment.
• Owner: The package manager.
• Approval gate: No subcontractor starts work without a signed pre start record.

Stage 8: Manage the interfaces on site as a live document

Interfaces move as the work proceeds, and when they do the schedule has to move with them. Review it at the weekly coordination meeting, record any reassignment in writing and reflect any commercial consequence in the relevant subcontract account immediately. An interface reassigned verbally becomes a claim from one party and a credit nobody chases from the other.

• Deliverable: A maintained interface schedule with a change log and the commercial effect recorded.
• Owner: The package manager with the commercial manager.
• Approval gate: Every interface reassignment has a written record and a commercial entry.

Handovers between stages

The handover that creates most gaps is from procurement to site. The person who wrote the scope and the interface schedule understands exactly where the boundaries sit, and the person running the site often receives only the subcontract order. Walk the site team through the interface schedule package by package at mobilisation, and keep it on the wall rather than in a folder. The second handover runs between packages: when one subcontractor finishes a surface another will build on, record the condition at the point of transfer, because otherwise every subsequent defect becomes an argument about who damaged it.

How you know it is finished

The packaging is complete when every element of the building appears in exactly one package, every interface has a named owner, every attendance is stated and no subcontractor is working without a signed pre start record. Test it by picking three awkward details, such as a duct through a fire wall, a roof upstand at a parapet and a threshold at an external door, and asking who does each part. If you get a clean answer for all three, the structure will hold.

Domira builds and supervises projects across Saudi Arabia, and the commercial discipline above is how its projects stay inside their budget and their programme. Send the drawings, the contract or the site and Domira will tell you where the risk actually sits.