The moment a roofing business grows beyond what the owner can personally deliver, subcontractors become part of the model. It is a natural and necessary step — but it is also the point where many contractors lose control of quality, get exposed to legal and tax liability they did not plan for, and find their hard-built reputation damaged by work they never touched.
Used well, subcontractors give you the ability to take on two or three jobs simultaneously, handle surge demand after storm events, cover specialist work outside your own core skills, and scale revenue without the full overhead of employed staff. Used poorly, they produce defects that cost more to fix than the job was worth, trigger HMRC investigations for CIS non-compliance, and generate one-star reviews from homeowners who reasonably expected the quality of the company they hired.
This guide covers every stage of the subcontractor relationship: how to find and vet subbies properly before you use them, what needs to be in a written agreement, how to brief and manage work in progress, how to handle the CIS requirements, payment structures that protect your cash flow, and how to manage the quality and reputation risks that come with work leaving your direct control.
When subcontracting makes sense — and when it doesn't
The decision to subcontract should be deliberate, not reactive. A contractor who subcontracts because they said yes to too many jobs without thinking it through is not managing subcontractors — they are firefighting. The right question is: what role should subcontractors play in my business model, and under what circumstances?
- Overflow capacity during peak periods or post-storm surges
- Specialist skills your own team does not cover (e.g. lead work, flat roofing systems)
- Geographic coverage for jobs outside your normal operating radius
- Scaling revenue without the commitment of permanent employment
- Testing demand in a new job type before investing in training or equipment
- Large project elements where a specialist gang is more efficient than your general team
- You have not met or worked with the subcontractor before
- The subcontractor has no verifiable insurance
- You have no written agreement in place
- You cannot visit the site during the job
- The subcontractor's rate leaves you with no meaningful margin
- You are doing it to avoid taking on an employee who should be employed
- You cannot describe clearly what the quality standard is before they start
Finding and vetting subcontractors: the non-negotiables
The best subcontractors come from the same places as the best employees: word of mouth, trade network referrals, and direct contact with people you have worked alongside. A subcontractor found through a cold ad or a quick search carries far more unknown risk than one recommended by another contractor whose judgment you trust.
Before a subcontractor works on a job under your name, there are four categories of vetting: documentation, competence, financial standing, and personal fit. All four matter.
Public Liability Insurance certificate
Minimum £1m cover, preferably £2m for roofing. Obtain the current certificate — not a screenshot, the actual document showing expiry date and covered activities. Check it specifically covers roofing and working at height.
CIS registration verification
Verify their UTR (Unique Taxpayer Reference) with HMRC via the CIS online service before the first payment. This tells you their deduction rate and confirms they are registered. Never pay a subcontractor without doing this — the penalty exposure is yours.
Proof of right to work in the UK
For self-employed individuals, you are not technically required to carry out right-to-work checks, but for labour-only subcontractors who work on your sites you carry reputational and practical risk if HMRC or the Home Office identifies an issue. A copy of a valid passport or biometric card is standard practice.
References from other contractors
Two named contractor references who can be called and asked directly: would you use them again, did they meet the quality standard expected, and were there any issues on site? A subcontractor who cannot provide references is a meaningful risk signal.
CSCS card (appropriate level)
A Construction Skills Certification Scheme card at the appropriate level for the work being carried out. For roofing, the relevant cards are Skilled Worker (blue) or Experienced Worker (gold). Operatives without a relevant CSCS card present issues on any commercial or managed site.
Evidence of relevant experience
Photos of comparable completed work, an example of a recent similar job, or a trial day on a lower-risk job before deploying on a customer-facing project. Do not rely on a subcontractor's self-assessment of their competence — see evidence of the work.
Own tools and equipment
A self-employed subcontractor who brings their own tools and equipment is a stronger indicator of genuine self-employment status for HMRC purposes, and practically reduces your equipment costs and logistics.
Cash-only, no paperwork, no UTR
A subcontractor who will only work cash in hand, refuses to provide a UTR, or says they "don't bother with all that" is putting HMRC liability on your business. Every contractor who uses this arrangement and gets caught pays the bill — not the subcontractor.
The written subcontract: what you need in writing before work starts
A written subcontract agreement does not need to be a 30-page legal document. It needs to be clear, specific, and signed by both parties before work commences. A one-page document that covers the following points is legally binding and protects you far better than a detailed verbal understanding.
📋 Subcontract agreement — what to include
CIS compliance: what you must do as a contractor
The Construction Industry Scheme (CIS) is one of the most commonly misunderstood compliance obligations in UK construction, and the area where roofing contractors most often get into serious trouble with HMRC. The obligations are straightforward once understood — but the consequences of getting them wrong are disproportionately severe.
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1Register as a contractor with HMRC
Any business that pays subcontractors for construction work — including roofing — must register as a contractor under CIS with HMRC. This is separate from your own tax registration. Register through HMRC's online CIS portal. Once registered, you will receive a contractor reference and be required to submit monthly CIS returns.
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2Verify every subcontractor before first payment
Before paying any subcontractor for the first time, you must verify them with HMRC via the CIS online service or by calling the CIS Helpline. Provide HMRC with the subcontractor's UTR (Unique Taxpayer Reference) and, if they are a company, their company registration number and VAT number. HMRC will confirm the subcontractor's deduction rate: 20% (registered), 30% (unregistered), or 0% (gross payment status).
✅ Keep a record of every verificationHMRC requires you to keep records of every CIS verification for at least 3 years. Note the verification reference number returned by HMRC for each subcontractor, the date of verification, and the deduction rate confirmed. If HMRC audits your CIS records and you cannot produce verification evidence, you are treated as liable for the unpaid deductions — regardless of whether the subcontractor paid their own tax.
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3Deduct tax at the correct rate from each payment
CIS deductions are applied to the labour element of each payment — not materials. If a subcontractor invoices you £1,000 for labour and £400 for materials they supplied, the CIS deduction is applied only to the £1,000 labour element. The deduction rate (20% or 30%) is applied to that figure. Pay the subcontractor the net amount (labour minus deduction, plus materials in full) and hold the deduction for payment to HMRC.
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4Provide monthly payment and deduction statements to subcontractors
Each month in which you make a CIS payment, you must provide the subcontractor with a written statement showing: the gross amount paid, the materials allowance, the deduction made, and the net amount paid. This statement is what the subcontractor uses to reclaim their tax deductions through their own self-assessment return. Failure to provide these statements is a separate CIS penalty, independent of any deduction errors.
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5Submit monthly CIS returns to HMRC by the 19th of the following month
Every month — even months where you made no CIS payments — you must submit a return to HMRC. The return lists all payments made to subcontractors in the month, the deductions applied, and the subcontractors' UTRs. Submit via HMRC's CIS online service, your accountant, or through accounting software like Xero or QuickBooks (which handle CIS calculations automatically). Pay the total deductions to HMRC by the 19th of the following month (22nd for electronic payment).
✅ Late filing penaltiesA CIS return filed even one day late triggers a £100 automatic penalty. Persistent late filing escalates: 3 months late = additional £200; 6 months = £300 or 5% of liability (whichever is higher); 12 months = another £300 or 5%. Set a recurring calendar reminder for the 15th of every month to submit and pay — giving yourself a buffer before the 19th deadline.
Employment status: avoiding the disguised employment trap
The most serious legal risk in subcontracting — more serious than CIS non-compliance — is using subcontractors in a way that HMRC considers to be disguised employment. If HMRC investigates and concludes that your subcontractors are actually employees in practice, you become liable for unpaid PAYE tax and National Insurance going back up to six years, plus penalties and interest. This has destroyed otherwise profitable roofing businesses.
HMRC uses a set of employment status tests to determine whether a working arrangement is genuinely self-employed or actually employment. The key factors are:
Substitution
Can the subcontractor send someone else to do the work in their place without your approval? Genuine self-employment allows substitution. If you require the specific individual to show up, HMRC views this as an employment indicator. Your written agreement should explicitly permit substitution (while requiring that any substitute meets the same competency standard).
Control
Do you control how and when the work is done, or only what the end result must be? Telling a subcontractor to start at 7:30am, take a specific lunch break, and work in a particular sequence looks like employment. Specifying the outcome (re-tile this roof to spec by Friday) and leaving the method to the subcontractor supports self-employment.
Mutuality of obligation
Are you obliged to offer work and is the subcontractor obliged to accept it? If you have a standing arrangement where they work for you exclusively and you guarantee a minimum amount of work, this looks like employment. Genuine subcontracting is project-by-project with no obligation on either side between engagements.
Equipment and financial risk
Does the subcontractor use their own tools and bear financial risk if the job goes wrong (e.g. they fix defects at their own cost)? Self-employed individuals typically bring their own equipment and bear the risk of losses. Providing all equipment and correcting defects at your cost both point toward employment.
Briefing subbies properly: the on-site setup that prevents most problems
The majority of subcontractor quality problems stem not from incompetence but from inadequate briefing. A subcontractor who does not know your quality standard cannot meet it. The site setup briefing is the most important management moment in the entire subcontracting relationship — and it takes 20–30 minutes if done properly.
- 📋Walk the job together before they start — physically walk the site with the subcontractor and explain what you expect the finished result to look like, any specific challenges or unusual features of this property, and any commitments you have made to the customer about timing, access, or finish quality. Do not assume they will infer these things from the scope document.
- 📸Take timestamped photos of the start condition — document the state of the property before any work begins. The roof, the scaffolding, the access routes, the garden, and any existing features that could be at risk. These photos protect you in any dispute about damage caused during the job.
- 🏠Introduce the subcontractor to the customer — or brief them on how to behave — the customer hired you and has your name on the quote. If they are going to be dealing with a subcontractor's team on site, they need to know that is happening and why. Brief the subcontractor: do not discuss the project financials with the customer, do not make commitments about additional work, and do not mention your company name if a dispute arises (refer all issues to you directly).
- 📞Establish a daily check-in protocol — agree that the subcontractor will send you a photo update at end of day (before they leave site) showing the day's progress and any issues encountered. This takes 60 seconds for them and keeps you informed without needing to be on site every day. Problems surface early rather than at practical completion.
- 🔍Do a mid-job quality check on any job longer than three days — visit the site yourself mid-way through. You will catch problems when they are still cheap to fix rather than after completion when remediation is expensive and the subcontractor has been paid. Check the specific technical details you briefed: ridge bedding, flashing details, tile alignment, waste management. A 30-minute site visit mid-job is worth more than a full day of remediation after handover.
- ✅Do a formal sign-off inspection before releasing final payment — walk the finished job against the scope, take completion photos, and check the same specific details as the mid-job visit. Only when you are satisfied that the work meets the standard should the subcontractor invoice you for the final balance. The financial leverage of outstanding payment is your primary quality control tool — do not give it up too early.
Payment structures that protect your cash flow
How and when you pay subcontractors has a significant impact on your cash flow and your quality control leverage. The wrong payment structure — paying in full upfront, or paying weekly regardless of progress — removes your ability to manage defects and leaves you exposed if the subcontractor walks off the job.
| Payment structure | Works well for | Risk | Recommendation |
|---|---|---|---|
| Full payment on completion | Small, 1–2 day jobs | Subcontractor may rush to finish; cash flow pressure on them for longer jobs | Good for short jobs — clean and simple |
| Day rate, paid weekly | Open-ended labour supply | No quality leverage; encourages slow working; ambiguous end point | Use only with trusted, established subbies |
| Fixed price with staged payments | Jobs over 3–5 days | Requires clear milestones in the subcontract; some admin overhead | Recommended — aligns payment with progress |
| Fixed price with 5% retention | Larger jobs with warranty exposure | Some subbies resist retention; must be agreed upfront in the contract | Best for jobs over £2,000 — protects against defects |
| Full payment upfront | Never appropriate | All quality and delivery leverage lost; no recourse if subcontractor disappears | Never do this — no exceptions |
The 40 / 55 / 5 payment model for medium jobs
For any roofing subcontract job lasting more than three days with a value above approximately £1,500, this staged payment structure balances the subcontractor's cash flow needs with your quality control requirements:
- 40% on commencement — released when the subcontractor mobilises on site and strip or preparation work begins. This covers their initial material and labour outlay without leaving them funding the entire job.
- 55% on practical completion — released after your sign-off inspection confirms the work meets the specification. This is the primary quality leverage moment — do not release it until you are satisfied.
- 5% retention held for 3–6 months — released after the defects liability period without any claims. This is your insurance against defects that appear after the job is finished and the subcontractor's attention has moved elsewhere.
Tell subcontractors about the retention arrangement before they agree to the job — not after. A subcontractor who feels ambushed by a 5% retention will resent it; one who agreed to it in the contract will accept it as a normal commercial term.
Protecting your reputation when work leaves your hands
Your reputation — your Google reviews, your word-of-mouth referral network, the trust you have built with customers — is the most valuable commercial asset in your business. Every subcontractor working under your name is a potential source of reputation damage if they behave differently on site than you do. Managing this risk requires deliberate systems, not just good intentions.
Branded presentation on site
Require subcontractors working under your name to wear your branded workwear or at minimum to not display competitor branding. A crew on your customer's roof wearing another company's polo shirts confuses the customer and undermines the relationship you built. Supply branded hi-vis vests or t-shirts if needed — the cost is negligible against the reputation value.
All customer communication through you
Subcontractors should not make commitments to customers about pricing, timelines, or additional work. If the customer asks about something the subcontractor cannot answer, the correct response is "I'll let [your name] know and they'll come back to you." Anything else creates expectation misalignment that eventually reaches you as a complaint.
Site cleanliness and end-of-day standard
Brief subcontractors on your minimum daily site cleanliness standard: materials stacked safely, debris cleared from the garden, tools not left visible on the roof, gutters unblocked. Customers notice the state of their property at the end of each working day and it directly influences the review they leave you.
Customer satisfaction check after handover
Call or visit the customer personally within a week of job completion. Ask specifically whether they are happy with the work and whether there is anything they want to raise. This catches concerns before they become reviews, and it signals that you care about the outcome — which is the primary driver of positive Google reviews from customers whose jobs were handled by subbies.
When things go wrong: handling defects and disputes
Even well-managed subcontracting relationships produce defects occasionally. How you handle them determines whether the situation costs you money, a customer, or both.
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1Respond to the customer immediately and personally
When a customer reports a defect in subcontracted work, your response to them should be identical to how you would respond if it were your own work: own it, apologise, and commit to a specific date to inspect or remedy. Do not tell the customer it was a subcontractor — they hired you, and the subcontracting arrangement is your commercial decision, not their problem.
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2Document the defect thoroughly before remediation
Before any remediation work begins, photograph the defect in detail. Note its location, extent, and probable cause. This documentation is the evidence you need to pursue the subcontractor for the cost of remediation under their defects liability obligation.
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3Notify the subcontractor formally and give them the first opportunity to remedy
Under your subcontract agreement, the subcontractor should have the first right to remedy their own defective work. Send a written notification (email is sufficient) describing the defect, providing the photographic evidence, and giving a reasonable deadline to attend and remedy — typically 5–10 working days for non-emergency defects. Keep a record of this notification.
✅ If they do not respondIf the subcontractor ignores your notification or refuses to attend, you have the right under the subcontract to engage an alternative contractor and charge the cost against any outstanding retention or pursue them for the amount. This is why retention and a written defects liability clause are essential — without them, your only route is a small claims court claim, which is time-consuming even when successful.
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4Remedy the defect from your own resources if necessary
If the customer's situation is urgent — a leak, structural risk, or significantly damaged finish — you may need to remedy the defect immediately regardless of whether the subcontractor has responded. Do it, document everything, and pursue the cost recovery from the subcontractor separately. Customer first, commercial recovery second.
Building a reliable subcontractor panel over time
The most effective subcontracting operations are not ones that use whoever is available from week to week — they are ones that maintain a small, reliable panel of vetted, proven subcontractors who understand your standards and can be deployed with minimal management overhead. Building this panel takes time but pays significant dividends in predictability and quality.
What a well-managed subcontractor panel looks like
3–5 core subcontractors or gangs who have worked for you before, whose quality you have personally verified, whose insurance you have on file, and with whom you have a signed standard agreement. You have references for them and they know your standards without needing to be briefed from scratch every time.
Tiered by job type and experience: a lead specialist for lead work and heritage properties; a flat roofing specialist for EPDM, felt, and GRP; a general pitched roofing gang for re-roofing and repair overflow; and ideally one geographic overflow contact for areas outside your primary radius.
Regularly reviewed: After every subcontracted job, rate the subcontractor against your standard: quality of finish, punctuality, customer interaction, site cleanliness, responsiveness to your communications. Keep a simple log. Over time this tells you who to prioritise and who to stop using before a problem becomes serious.
Treated as a relationship, not a transaction: Subcontractors who feel they are valued, paid on time, and communicated with respectfully are more reliable and more willing to prioritise your work when they are busy. Pay on time, every time. Brief clearly. Give feedback after jobs. The best subbies have choices about who they work for — make yourself the obvious first call.
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Frequently Asked Questions
What is the difference between a subcontractor and an employee in roofing?
A subcontractor is a self-employed individual or company engaged to carry out specific work under a contract for services. They are responsible for their own tax, National Insurance, and insurance. An employee works under a contract of employment with statutory rights including holiday pay, sick pay, and unfair dismissal protection. HMRC uses employment status tests — primarily around control, substitution, and mutuality of obligation — to determine the genuine position regardless of how the arrangement is labelled. Engaging someone as a subcontractor who is actually an employee in practice exposes you to significant HMRC liability for unpaid PAYE and National Insurance.
Do roofing subcontractors need their own public liability insurance?
Yes — any subcontractor you engage should carry their own public liability insurance, typically with a minimum limit of £1 million and ideally £2 million or more for roofing work. Obtain a copy of their current insurance certificate before they start on any job. Your own public liability policy may not cover work carried out by uninsured subcontractors, meaning you could be personally liable for damage or injury caused by a subcontractor operating without their own cover.
What is the Construction Industry Scheme (CIS) and does it apply to my roofing subcontractors?
The Construction Industry Scheme is an HMRC tax deduction scheme that applies to most construction work in the UK, including roofing. If you pay subcontractors for construction work, you must register as a CIS contractor, verify each subcontractor with HMRC before the first payment, deduct tax at the verified rate from labour payments (20% for registered, 30% for unregistered), provide monthly payment statements to subcontractors, and submit monthly CIS returns to HMRC. Failure to comply can result in HMRC treating you as personally liable for the unpaid deductions plus penalties and interest.
How should I price jobs when using subcontractors?
Price the job for the customer independently based on the full scope, materials, overhead, and your profit requirement — then negotiate the subcontractor's rate separately to protect your margin. A common approach is to mark up subcontractor labour rates by 15–25% as a minimum, with materials typically marked up separately. Never price the job first to establish your subcontractor's rate and then add a margin — this compresses your pricing and removes your flexibility to absorb unexpected costs during delivery.
Am I liable for defects in work carried out by my subcontractors?
Yes. As the main contractor who contracted with the homeowner, you are legally responsible for the quality of all work delivered under that contract — regardless of whether you used your own operatives or subcontractors. If a subcontractor's work is defective, the homeowner's remedy is against you. You can then pursue the subcontractor for their failure under your subcontract agreement, which is why a written subcontract with clear defects liability provisions, retained payment, and insurance requirements is essential before any subcontractor starts on a customer-facing job.
What should be in a written subcontract agreement for roofing work?
A written subcontract for roofing work should include a clear scope of work and specification, agreed rate or lump sum price, payment terms (including any staged payments and retention), insurance requirements, health and safety obligations, a defects liability period and remedy process, a non-solicitation clause preventing the subcontractor from approaching your customers directly, and a termination provision. It does not need to be a lengthy legal document — a clear, plain-language agreement that both parties sign before work commences is legally binding and offers significantly more protection than any verbal arrangement.
More capacity needs more leads to fill it
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