Key takeaways
- The Question: How should a main contractor select, contract, coordinate, measure and pay its subcontractors so that the project runs as one team rather than a chain of disputes?
- The Answer: Most problems with subcontractors are set up before they start work: weak prequalification, unclear scope boundaries and no agreed way to measure progress. Fix those, then run a weekly routine built on commitments and constraints, measure performance from records both sides accept, and pay against evidence on time.
- The YelloSKYE Angle: Disagreements between contractors and trades usually turn on what was on site and when. Construct IQ gives both sides the same dated, located record of every area, which supports valuations, hand-offs and change claims without a site walk to argue over.
Subcontractor management is how a main contractor selects, contracts, coordinates, pays and closes out the specialist firms that build most of a project. On a typical building, the main contractor's own staff manage and coordinate while subcontractors deliver the bulk of the physical work, so the quality of these relationships largely decides cost, programme and quality. The process runs from prequalification to the final account, and most of the failures that surface late in a project can be traced back to choices made at its start.
This guide follows that lifecycle from the main contractor's side. It also covers how to judge a trade's performance from facts rather than blame, which is where Construct IQ is useful: a shared visual record of the site settles many questions before they become arguments.
The subcontract lifecycle at a glance
| Stage | The main contractor's aim | Key outputs | Typical failure |
|---|---|---|---|
| Prequalification | Shortlist firms able to deliver this package now | Approved list, capacity check | Choosing on reputation without checking current workload |
| Tender and award | Compare like with like and close scope gaps | Scope documents, interface matrix, subcontract | Lowest price wins with exclusions unread |
| Onboarding | Get the firm working safely and to the plan from day one | Induction, method statements, programme sign-up | Mobilising before drawings and areas are ready |
| Delivery | Keep the trade productive and coordinated | Weekly plans, inspections, progress records | Status argued from memory |
| Payment | Pay accurately and on time against evidence | Valuations, payment notices | Under- or over-valuation that sours the relationship |
| Change and dispute | Price and settle changes as they happen | Instructions, variations, records of condition | Changes left to the final account |
| Close-out | Finish, hand over and release retention | Completed snags, documentation, final account | Long tail of open items and unpaid sums |
Prequalification and selection
Prequalification answers one question: can this firm deliver this package, on this project, at this time? A strong company with too much work already is as much of a risk as a weak one.
A practical prequalification covers:
- Financial standing, through accounts or a credit check, sized against the value of the package.
- Insurance, including employer's and public liability and, for design work, professional indemnity.
- Health and safety record and the systems behind it, not only accident statistics.
- Quality management, such as inspection and test plans for similar work.
- Relevant experience, with references from recent projects of similar type and scale.
- Current workload and labour against what the programme will need at peak.
- Design capability, where the package includes contractor design.
At tender stage, normalise bids before comparing them. List every exclusion and qualification, price the ones you would have to cover yourself, and only then compare totals. The cheapest bid often becomes the most expensive once the gaps are filled.
Scope and interfaces
Most disputes between trades start where one package meets another. Each subcontractor prices what its scope document describes, and anything that falls between two documents is priced by no one.
The tool for closing these gaps is an interface or responsibility matrix: a table of every shared item with a single named owner. A few examples:
| Interface item | Common owner | Why it causes trouble |
|---|---|---|
| Fire stopping around service penetrations | Fire stopping specialist or the trade making the hole | Each service trade assumes someone else seals its openings |
| Builder's work in connection with services | Main contractor or drylining package | Openings, bases and supports are needed by many trades |
| Making good after another trade | The trade that caused the damage, or a nominated package | Hard to attribute without a record of condition |
| Temporary power, lighting and hoisting | Main contractor | Assumed to be free and always available |
| Waste removal and cleaning | Each trade, or a site-wide package | Areas handed over dirty delay the next trade |
| Setting out | Main contractor for primary grids; trades for their own work | Errors are found late and disputed |
Attendances, meaning the facilities the main contractor provides to each trade, belong in the same exercise. If a subcontractor expects crane time, scaffold or storage, write down how much and when.
Onboarding and mobilisation
The first fortnight of a subcontract sets the tone for the rest. A firm that arrives to find no drawings, no access and no clear work area will lose time it may later try to recover through claims.
Before mobilisation, confirm that the trade has:
- Current information, including approved drawings, specifications and answers to open queries.
- Agreed method statements and risk assessments reviewed by the site team.
- A programme it has helped to build, with durations its own supervisors accept.
- Defined first work areas that are genuinely ready, with access and temporary services in place.
- Site induction for every operative, and clarity on who supervises them.
- The project's quality plan, including hold points and how inspections will be booked.
- Access to the project's shared records, so the trade sees the same drawings, plans and site captures as the main contractor.
Record the condition of each area at the moment it is handed to the trade. That single record avoids many later arguments about damage and making good.
Weekly coordination
Once trades are on site, a weekly cycle of looking ahead, removing constraints and agreeing commitments keeps them productive. The mechanics of that cycle, including lookaheads, area hand-offs and coordination meetings, are covered in detail in our construction coordination guide, and the planning method behind it in lean construction.
From a subcontractor management point of view, three habits matter most. Ask trade supervisors to commit only to work that is free of constraints. Record whether last week's commitments were met and, if not, why. And treat a constraint the main contractor owns, such as a late drawing or a blocked area, with the same urgency you would expect from a trade.
Measuring performance without blame
Without agreed measures, performance reviews become a contest of opinions. The main contractor says the trade is under-resourced; the trade says the areas were never ready. Often both are partly right, and nobody can prove which delay came first.
Agree the measures at contract stage
Choose a short list that both sides accept before work starts, and attach it to the subcontract. A workable set:
| Measure | What it shows | Where the data comes from |
|---|---|---|
| Progress against plan, by area | Whether the trade is keeping pace | Dated captures or measured quantities per zone |
| Commitment reliability | How often weekly promises are kept | Weekly work plan records |
| Reasons for missed work | Whose constraint caused each miss | Weekly review notes |
| First-time inspection pass rate | Quality of work at hold points | Inspection records |
| Defect close-out time | Responsiveness once issues are raised | Issue log |
| Work left incomplete in released areas | How often the trade moves on before finishing | Comparison of captures before and after hand-off |
| Safety observations | Site behaviour and supervision | Safety inspection records |
Measure from a shared record
Measures only reduce conflict if both sides trust the source. A progress figure from the main contractor's spreadsheet invites a counter-figure from the trade's. A dated visual record of each area, open to both, does not, because the question becomes what the capture shows rather than whose report to believe.
Look at causes before conclusions
A trade that is behind in an area that was handed over late, without drawings or with another trade still working in it, is not underperforming. Check readiness before assigning a delay. Reviewing performance this way is fairer, and it also shows the main contractor where its own processes are letting trades down.
Hold a short performance review with each major trade every month, using the same measures each time. Problems raised early can be fixed with resources; problems raised at the final account can only be fought over.
Payment
Prompt, accurate payment is the most practical way to keep a good subcontractor committed to a project. Late or disputed payments push trades to move their best supervisors elsewhere.
- Agree the method of valuation before work starts: measured quantities, milestones or an activity schedule.
- Value against evidence of work in place, not against claims alone.
- Issue notices on time and explain any difference between the claim and the valuation.
- Keep retention and payment terms clear in the subcontract. Many countries have statutory rules on payment timing and notices in construction, such as the UK's Housing Grants, Construction and Regeneration Act 1996 or the prompt payment laws in many US states, so check the ones that apply.
Aligning site capture with the valuation date removes much of the debate. In our contractor billing disputes use case, drone flights are timed to the billing cycle so the contractor, project manager and owner review the same timestamped site before a claim is approved, and verified deployments needed 80 per cent fewer site visits to do it.
Changes, back-charges and disputes
Changes are normal; leaving them unrecorded is what turns them into disputes. Arcadis's annual Global Construction Disputes Report regularly lists poor contract administration and incomplete or unsubstantiated claims among the leading causes of disputes, and both come down to records.
- Instruct in writing, even when the instruction was given on site.
- Record the condition before and after work affected by a change, with dates and locations.
- Notify back-charges promptly, with evidence of the damage or defect and who caused it, as the subcontract requires.
- Settle variations monthly where possible, rather than leaving them to the final account.
- Escalate in steps: site discussion, commercial meeting, senior management, then the contract's formal procedure.
Trades are increasingly keeping their own records for the same reasons; our guide to reality capture for subcontractors looks at it from their side, and construction dispute documentation covers what a record needs to hold up in a formal dispute.
Where a visual site record fits
YelloSKYE does not manage subcontracts, payments or labour. What Construct IQ provides is the record of the site that those processes depend on. Drone flights cover the frame and external works, 360° walks cover interiors and fixed cameras watch priority zones. DEX keeps every capture on one timeline that both the main contractor and its trades can open. Problems are pinned to their exact location on the captures, the 4D view sets what was built against what the programme expected, and the history can be stepped through day by day to see what was in place on a given date. For teams already running their subcontracts in Procore, Autodesk BIM 360 or Autodesk Construction Cloud, progress data flows into those tools.
On a fit-out floor with many trades, that shared record shortens the conversations that eat a site manager's week: walkable 360° records brought a 70 per cent drop in coordination time on our interior fit-out project. Where zones need continuous attention, such as a loading bay several trades depend on, fixed-camera construction monitoring gives a constant view and raises an alert if work in that zone goes quiet.
Subcontractor management checklist
- Prequalify for this package and this programme, including current workload.
- Normalise bids by pricing exclusions before comparing totals.
- Build an interface matrix with one owner for every shared item, and list attendances.
- Mobilise only into ready areas, with drawings, access and an agreed programme.
- Record each area's condition at hand-off to the trade.
- Agree performance measures in the subcontract and review them monthly.
- Value against evidence on the valuation date and pay on time.
- Record and settle changes as they happen, not at the final account.
