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. Deviate from it and you create expensive problems. The standard residential sequence:

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

2. Masonry and superstructure: Bricklayers and blocklayers building the walls to plate level. On cavity wall construction, cavity insulation goes in as the walls rise. Coordinate this with the bricklayer at the start, not as an afterthought mid-build.

3. Roof: Roofer installs the structural roof, rafters or trusses, sarking, felt, battens, tiles. The building must be weathertight before internal trades start. No exceptions.

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

5. Insulation and boarding: Insulation between rafters where 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 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 go down.

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 creates quality problems that cost more to fix than the time saved. I've seen brand-new oak floors buckle because they went down over a screed that wasn't dry. The floor cost more to replace than the entire saving from running the programme faster. Every time.

Booking Subcontractors

Good subcontractors are busy. The best bricklayers, roofers, and plasterers in any area are typically booked 4–8 weeks ahead. Call today needing someone in two weeks and you'll get whoever is available, not whoever is best. Book your trades when you know the programme. Not when the previous trade finishes. Sequence the bookings as you build out the programme, not reactively.

Give subcontractors a firm start date, a realistic programme duration, and call them the week before to confirm. Subcontractors who aren't called to confirm often take a different job that came up at shorter notice. That is not disloyalty. It is business. Your job is to keep the sequence confirmed and visible to everyone on the project.

Contracts and Pricing: Protect Yourself Without Creating Enemies

Written Subcontracts

Every subcontract should be in writing. It does not have to be complicated. A subcontract letter or order covering 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.

A handshake deal on a five-figure subcontract is a gamble. Most of the time nothing goes wrong and the informality doesn't matter. But when a dispute arises about scope, quality, or payment, the absence of a written record means it gets resolved by whoever is most willing to walk away from money or from completing the job. Neither outcome is good. Written subcontracts give both parties somewhere to stand.

Fixed Price vs Daywork

Get a fixed price for subcontract work wherever the scope can be clearly defined. A fixed price means the subcontractor carries the productivity risk. If it takes them longer than expected, that is their problem. Daywork means you carry it. For most trades on a well-designed project, fixed prices are achievable: brickwork priced per m², roofing per m², plastering per m², joinery 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, specialist repair work. In these cases, agree a daywork rate schedule before any work starts, covering labour, plant, and materials separately with markups specified. Agreeing to pay "cost plus" without knowing what the rates are is a blank cheque.

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 or labourer: £150–220 per day. All plus VAT if the subcontractor is VAT registered. London and South East rates typically run 20–30% above these.

Retention

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

Use retention consistently and tell subcontractors about it at the start of the engagement. It should not be a surprise. Most experienced subcontractors expect it. The practical effect is that the retained sum gives the subcontractor a reason to come back and complete snagging work. A subcontractor who has been fully paid before the snagging list is finished has a much weaker reason to rebook a half-day of remedial work when they're already on to the next job.

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, not waiting until the whole job is done. A bricklayer who has built 60 courses with mortar joints 2mm too wide has a much bigger problem if you tell them at the top than if you catch it at the fifth course. The 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. No exceptions.

Brickwork: Check perpend joints are not running in a continuous vertical line for more than two courses. Check the mortar joint profile is consistent with the specification. Check gauge every five to ten courses with a rack-and-pinion gauge. 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 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 WhatsApp message with a photograph of the defect and a clear statement of what needs doing is enough to create a record. If the subcontractor disputes the required standard, refer to the specification in the subcontract. If there is no specification, you are in a weaker position. That is the strongest argument for having a clear written scope before anyone picks up a tool.

Payment: Pay on Time, Every Time

Why Prompt Payment Matters

The most reliable way to keep good subcontractors coming back is to pay them on time, every time. This sounds obvious. It is widely ignored. Contractors who use subcontractors' payment terms as a cash flow management tool, withholding payment or paying late without communication, signal that they are a risk to work with. The best subcontractors have choices. They will quietly deprioritise 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: 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 has driven a significant number of subcontractor insolvencies. Paying on time is not just fair. 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% released at end of defects period (with 2.5% retained at practical completion). Both parties can see what triggers each payment. That removes ambiguity and reduces the arguments.

Communication: The Underrated Management Tool

Weekly Briefings and a Master Programme

On a project with multiple trades running concurrently, a brief weekly conversation with each trade to confirm the following week's programme prevents most 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 neither can work in the room at the same time. This is avoidable with a 15-minute phone call.

A master programme on the wall of the site office, even a printed Gantt chart from a spreadsheet, showing every trade's start and finish dates for each area of the building, is the single most useful management tool on a live site. Update it weekly. Make it visible to everyone working on the project. Subcontractors who can see where they sit in the sequence 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. The ground will throw up something unexpected. The response to these events, fast and focused on solutions rather than blame, determines whether the problem becomes a crisis or a managed setback. The contractor or project manager who identifies a problem on Monday, makes a decision on Tuesday, and has a solution in place by Wednesday runs projects that deliver. The one who is still trying to apportion blame on Wednesday does not.