Managing Subcontractors on a Building Site: What Works and What Doesn't

Programme and Sequencing: Get This Right First

The Trade Sequence

The basic sequence on a new build or major extension is fixed by the logic of how buildings go together. Deviating from it creates expensive problems. The standard sequence for a residential project:

1. Groundworks: Excavation, drainage, foundations, ground slab. Everything else sits on this. Groundworks delays ripple through the entire programme.

2. Masonry / superstructure: Bricklayers and blocklayers building the walls to plate level. On cavity wall construction, cavity insulation is installed as the walls rise — coordinate with the bricklayer, not as an afterthought.

3. Roof: Roofer installs the structural roof — rafters or trusses, sarking, felt, battens, and tiles. The building must be weathertight before internal trades start.

4. First-fix plumbing and electrics: Once weathertight, plumber runs pipework and electrician runs cables before any boarding out. These must be coordinated so they don't cross in the same stud void.

5. Insulation and boarding: Insulation between rafters (if applicable), vapour barriers, plasterboard to walls and ceilings.

6. Plastering: Wet plaster or skim coat over board. Plastering must be complete before any second fix or floor finishes — wet plaster needs to dry properly (typically 4–6 weeks for full moisture loss) before final decoration.

7. Floor screed: Often installed at the same stage as plastering or immediately after. Screed also needs to dry before floor finishes are installed.

8. Second-fix plumbing: Radiators, sanitaryware, kitchen connections, boiler commissioning.

9. Second-fix electrics: Sockets, switches, light fittings, consumer unit testing and certification.

10. Joinery second fix: Doors hung, architraves and skirtings, fitted furniture.

11. Tiling and floor finishes.

12. Decoration.

13. Snagging and commissioning.

Trying to compress this sequence — having plasterers on site before the roof is fully weathertight, or floor finishes installed before plaster is dry — causes quality problems that cost more to rectify than the time saved by rushing. I've seen brand-new oak floors buckle because they were installed over a screed that wasn't dry. The floor cost more to replace than the entire saving from accelerating the programme.

Booking Subcontractors

Good subcontractors are busy. The best bricklayers, roofers, and plasterers in any area are typically booked 4–8 weeks ahead. If your programme requires them on site in two weeks and you call them today, you will get whoever is available — not necessarily whoever is best. Book your trades when you know the programme, not when the previous trade finishes. This means sequencing the bookings as you build out the programme, not just dealing with each trade as the previous one comes off.

Give subcontractors a firm start date, a realistic programme duration, and call them the week before their start to confirm. Subcontractors who aren't called to confirm often end up starting a different job that came up at shorter notice. This is not disloyalty — it's business. Your job is to manage the programme so that your trade sequence is confirmed and visible to all parties.

Contracts and Pricing: Protect Yourself Without Creating Enemies

Written Subcontracts

Every subcontract should be in writing. This does not have to be a complex legal document. A subcontract letter or order that sets out: the scope of work, the price, the programme, the payment terms, the insurance requirements, and the defects liability period is enough for most residential work. The key is that both parties have signed it and know what was agreed.

Handshake deals on a five-figure subcontract are a gamble. Most of the time, nothing goes wrong and the informality doesn't matter. But when it does go wrong — a dispute about scope, a quality failure, a payment argument — the absence of a written record means the dispute is resolved by whoever is most willing to walk away from money or from completing the job. Written subcontracts give both parties a framework for resolving disputes before they become legal ones.

Fixed Price vs Daywork

Always try to get a fixed price (lump sum) for subcontract work where the scope can be clearly defined. A fixed price means the subcontractor carries the risk of productivity — if they take longer than expected, that is their problem. Daywork rates mean you carry that risk. For most trades on a well-designed project, fixed prices are achievable: brickwork priced per m², roofing priced per m², plastering priced per m², joinery priced on a schedule.

Daywork is appropriate where the scope genuinely cannot be defined in advance — complex groundworks in uncertain ground, alteration work in an existing building where you don't know what's behind the walls, or specialist repair work. In these cases, agree a daywork rate schedule in advance (labour, plant, and materials separately, with markups specified) rather than agreeing to pay "cost plus" without knowing what the rates are.

Typical 2026 daywork rates for common trades: bricklayer: £240–320 per day (not including materials or hod carrier). Groundworker: £250–350 per day. Electrician: £250–380 per day. Plumber: £260–380 per day. Plasterer: £220–320 per day. General operative / labourer: £150–220 per day. These are all plus VAT if the subcontractor is VAT registered. London and South East rates are typically 20–30% above these figures.

Retention

Retention is a percentage of the contract value withheld at each payment stage as security for the contractor's obligations, particularly the obligation to rectify defects. The standard on a residential project is 5% retention held throughout the works, with 2.5% released at practical completion and the remaining 2.5% released at the end of the defects liability period (typically 6–12 months).

Use retention consistently and explain it to subcontractors at the start of the engagement — it should not come as a surprise. Most experienced subcontractors expect it. The practical effect is that the subcontractor is incentivised to return and complete snagging work, because the retained sum is not released until they do. A subcontractor who has been fully paid before the snagging list is complete has much less incentive to come back quickly for a half-day's remedial work.

Quality Control and Inspections

Check Work at Key Stages — Not Just at the End

The most effective quality management on a building site is checking work at critical stages rather than waiting until the whole job is done. A bricklayer who has built 60 courses of brickwork with the mortar joints 2mm too wide has a much bigger problem if you tell them at the top than if you tell them at the fifth course. The practical checkpoints vary by trade:

Groundworks: Inspect excavation depth and width against the structural engineer's foundation design before concrete is poured. Check drainage falls with a spirit level before backfilling. Once concrete is poured and drains are buried, defects are very expensive to remedy.

Brickwork: Check perpend joints (the vertical mortar joints) are not running in a continuous vertical line for more than two courses. Check the mortar joint profile is consistent with the specification (tooled, flush, recessed). Check gauge (the consistency of course heights) every five to ten courses — a rack-and-pinion gauge is the tool for this. Check wall ties are specified correctly and installed at the correct centres.

Roofing: Check tile gauge before the bulk of the roof is tiled — one row of tiles out of gauge at the eaves means the whole roof is wrong. Check valley flashings and ridge details before felt goes under them. Check ridge and hip fixings are clipped, not just bedded.

First fix: Check that pipe and cable routes have been agreed and are clear before boarding begins. Plumber and electrician must coordinate — conflicts in the same stud void are common and expensive once the boards are on.

When Work Is Not to Standard

When work is not to the required standard, address it immediately and in writing. Verbal instructions to redo work are unreliable — they get forgotten, disputed, or reinterpreted. A brief written instruction (even a WhatsApp message with a photograph of the defect and a clear statement of what needs to be done) creates a record. If the subcontractor disputes the required standard, refer to the specification that forms part of the subcontract. If there is no specification, you are in a weaker position — which is the strongest argument for having a clear written scope before work starts.

Payment: Pay on Time, Every Time

Why Prompt Payment Matters

The most reliable way to keep good subcontractors returning to your sites is to pay them on time, every time. This sounds obvious but it's widely ignored by contractors who use subcontractors' payment terms as a form of cash flow management. Withholding payment beyond agreed terms — or paying late without communication — signals that you're a risk to work with. The best subcontractors, who have choices about which contracts they take, will quietly de-prioritise your work in favour of clients who pay correctly.

The Construction Act (Housing Grants, Construction and Regeneration Act 1996, as amended) gives subcontractors legal rights around payment including the right to be paid within agreed terms, the right to suspend work for non-payment, and access to adjudication for payment disputes. These rights exist because late payment is endemic in the UK construction industry and has caused a significant number of subcontractor insolvencies. Observing the legal payment terms is not just fair practice — it protects you from legal exposure.

Agreed Payment Milestones

For most residential subcontracts, payment in stages tied to physical milestones is simpler and fairer than a fixed weekly or monthly cycle. Example milestones for a brickwork subcontract: 25% at damp proof course level, 50% at first floor sill level, 75% at wall plate, 90% at practical completion of brickwork, 2.5% at end of defects liability period (with 2.5% retained at practical completion). Both parties can see what triggers a payment, which removes ambiguity and reduces disputes.

Communication: The Underrated Management Tool

Weekly Briefings and a Master Programme

On a project with multiple trades running concurrently, a weekly briefing — even a brief 15-minute conversation — with each trade to confirm the programme for the following week prevents the majority of sequencing conflicts. Trades that don't know the other trades' programme create clashes: the electrician arrives to second fix on the same day the carpenter is fitting doors, and nobody can work in the same room at the same time.

A master programme on the wall of the site office (even a printed Gantt chart from a spreadsheet) that shows every trade's start and finish dates for each area of the building is the single most valuable management tool on a live site. It should be updated weekly and visible to everyone working on the project. Subcontractors who can see their own slot in the programme — and can see what other trades are doing before and after them — tend to manage their own time better than those who simply turn up and work until the job is done.

When Things Go Wrong

Things will go wrong on any building project of substance. A subcontractor will fail to show up on a critical day. A material will arrive damaged. An unforeseen condition in the ground will delay the groundworks. The response to these events — fast, calm, and focused on solutions — determines whether the problem becomes a crisis or a managed setback. The contractor or project manager who can identify a problem on Monday, make a decision by Tuesday, and have a solution in place by Wednesday is the one who runs projects that deliver on time. The one who spends Wednesday trying to apportion blame for Monday's problem is not.