How to Manage Subcontractors as a Trade Business (Without Losing Control)

Using subcontractors is one of the fastest ways to grow a trade business without the full cost and commitment of employment. Done well, it gives you flexibility, extra capacity, and the ability to take on more work than you could handle alone. Done badly, it leaves you with quality problems, unhappy customers, compliance headaches, and margins that make no sense. This guide covers everything you need to run subbies professionally — from the CIS paperwork to keeping your name on the job.

When to use subcontractors vs hiring employees

The right time to bring in a subcontractor is when you have more work than you can personally deliver, but not enough consistent volume to justify a permanent hire. A good rule of thumb: if you need extra hands for more than three months continuously, it is worth at least exploring whether an employee makes more financial sense. Below that threshold, subbies give you the capacity without the ongoing overhead.

Employees give you more control over working hours, training standards, and how they represent your business. Subcontractors bring their own tools, insurance, and independence — and under genuine self-employment, they are free to work for others. HMRC takes employment status seriously. If your subcontractor works exclusively for you, follows your instructions to the letter, and uses your tools on your schedule, HMRC may deem them an employee — with back-tax consequences for both parties. Use IR35 and employment status tests if you are unsure.

CIS registration and deductions explained

If your trade business operates in construction — building, plumbing, electrical, heating, roofing, groundwork and most related trades — you are almost certainly operating under the Construction Industry Scheme (CIS). As a contractor, you are legally required to register with HMRC as a CIS contractor before you make your first subcontractor payment. You must also verify each subcontractor with HMRC before paying them for the first time.

The verification result determines what deduction rate applies. A subcontractor with gross payment status pays no deduction — they handle their own tax in full. A verified subcontractor (registered but not gross-status) has 20% deducted at source. An unverified subcontractor — one HMRC cannot find on their system — has 30% deducted. You pay the deducted amounts to HMRC monthly and issue each subcontractor a CIS payment and deduction statement.

Written subcontractor agreements

A handshake or a WhatsApp message is not a contract. Before a subcontractor starts work, you need a written agreement that covers at minimum: the scope of work, the agreed rate, payment terms, who supplies materials, who holds public liability insurance for on-site damage, and what happens if the work is not completed to standard. This document also helps support the genuine self-employment relationship — a clear agreement that the subcontractor is free to substitute themselves or work elsewhere is evidence of independence.

Standard subcontractor agreements for the construction industry can be purchased from industry bodies, but many trade businesses use a simple two-page document drafted by their accountant or solicitor. The key point is having something signed before work begins — not after a dispute has arisen.

Setting day rates vs piece rates

You can pay subcontractors by the day or by the job. Day rates are simpler and give you flexibility if the scope changes. Piece rates — paying per unit of work completed, such as per radiator fitted or per circuit wired — give you a more predictable cost per job and incentivise the subcontractor to work efficiently. The right choice depends on the predictability of the work.

For most trade subcontracting, day rates work well for larger, variable jobs and piece rates work well for repetitive or volume work. Whatever you agree, write it down in advance and ensure the subcontractor understands exactly how variations outside the original scope will be handled. Scope creep without agreed pricing is where most subcontractor disputes begin.

Quality control: photos, checklists and customer sign-off

When a subcontractor works on a job under your business name, every quality issue becomes your quality issue. The customer called you, hired you, and paid you. If the work is poor, your reputation takes the hit — not the subby's. Protecting your name requires a quality process that does not rely on trust alone.

Require photo documentation at key stages: before starting, during installation, and on completion. A quick site checklist shared via WhatsApp or a simple form ensures the subcontractor covers every required element. Where possible, carry out a brief snagging visit before the customer signs off, particularly on higher-value jobs. If a snagging visit is not possible, request a photo walkthrough before payment is released. Customer sign-off — either in person or via a simple satisfaction confirmation message — protects you from later disputes about completion quality.

Payment terms that work: why 14 days makes sense

The standard payment term for subcontractor invoices is 14 days from invoice date. This gives you enough time to invoice the end customer, receive payment, and pass the subcontractor's net amount through to them without creating a cash flow gap. If you are on 30-day customer payment terms but paying subbies in 7 days, you will routinely be out of pocket waiting for the customer payment. Align your inbound and outbound terms carefully.

Make payment contingent on receiving a valid CIS invoice from the subcontractor, including their UTR number and a breakdown of labour and materials. This is not just good practice — it is a requirement for your monthly CIS return. Subcontractors who understand CIS will provide this automatically; those who do not will need training on what you require.

Keeping your name on the job

One of the most common mistakes trade businesses make with subcontractors is letting the subby deal directly with the customer. This creates two problems. First, your customer relationship is now with someone who is not employed by you. Second, you risk the subcontractor approaching that customer directly for future work — cutting you out entirely.

Keep all customer-facing communication going through your business. Introduction messages, progress updates, completion confirmations, and review requests should all come from you — or from your systems. The subcontractor should introduce themselves as working for your company when they arrive on site. This maintains the customer relationship in the right place and protects the goodwill you have built.

Tracking subcontractor costs per job for real profitability

Many trade businesses that use subcontractors heavily find themselves turning over good revenue but ending the year with poor profit margins. The reason is almost always that subcontractor costs are not tracked per job. If you quote a job at £3,200, pay a subcontractor £1,400, spend £600 on materials, and add in fuel, insurance allocation, and your own time quoting and managing the job, your actual margin can look very different from what you expected.

Trade2Base lets you log subcontractor costs directly against a job record, so every job has a visible profit figure. When you can see job-level profitability across all the work you have run through subbies, patterns emerge: certain job types are reliably profitable, others consistently thin. That visibility allows you to price future work more accurately and make better decisions about which jobs to take on.

Running subbies well is a system, not a relationship

The trade businesses that manage subcontractors effectively do not rely on good relationships alone. They have written agreements, clear CIS compliance processes, quality checkpoints, and job-cost tracking baked into how they operate. The relationship matters — reliable, high-quality subcontractors are worth holding onto — but the system is what stops things from going wrong when pressure is on and jobs are running in parallel.

• Register as a CIS contractor before your first subcontractor payment
• Verify every subcontractor with HMRC to confirm the correct deduction rate
• Use written agreements — scope, rate, insurance, quality expectations
• Require photo sign-off before releasing payment on completion
• Keep customer comms with your business — never let the subby build a direct relationship
• Track costs per job — revenue is vanity, margin is reality