At some point most engineers and construction professionals ask whether they would be better off contracting. The headline day rates can look generous next to a staff salary, and the idea of choosing your own projects is appealing. Permanent roles, meanwhile, offer stability, structured progression and benefits that are easy to overlook until you no longer have them. Neither option is better in general. The right answer depends on your stage of career, your appetite for risk and the kind of work you want to be doing in five years. This article sets out the questions worth asking before you switch in either direction.
Compare total value, not headline figures
Comparing a day rate with an annual salary is misleading unless you account for everything a permanent role includes. Staff employees typically receive paid holiday, bank holidays, sick pay, employer pension contributions, and often private medical cover, training budgets and professional subscriptions. A contractor pays for all of those out of their rate, and is not paid at all for days not worked.
A more honest comparison considers:
- how many days a year you would realistically bill, allowing for holidays, illness and gaps between contracts;
- the cost of pension contributions you would need to make yourself;
- insurance, accountancy fees and any umbrella company charges;
- professional subscriptions, CPD and software or equipment you would fund personally.
When those are added up, the gap is often narrower than it first appears. For some people contracting is still clearly more lucrative; for others the difference is modest once the risk is priced in.
Understand IR35 and how you will be engaged
The off-payroll working rules, commonly called IR35, are central to any decision about contracting through your own limited company. Since the reforms extended to the private sector, medium and large end clients are responsible for deciding whether an engagement falls inside or outside IR35 and for issuing a status determination. Small clients are treated differently, with the contractor's own company making the assessment.
In practice, many construction and engineering roles are assessed as inside IR35, particularly where the contractor works under similar supervision and control to employees. An inside determination means tax and National Insurance are deducted much as they would be for an employee, which significantly changes the financial picture. Many contractors in that position work through an umbrella company instead of their own limited company.
Before accepting a contract, ask how the client has assessed it, and get independent advice from an accountant who understands contractor tax. The rules are detailed, change from time to time and are beyond the scope of a general article, so treat any figures you see quoted online with caution.
Think about progression and skills
Contracting tends to reward existing expertise. Clients bring in contractors to fill a gap quickly, which means they want someone who can perform from the first week. That suits experienced engineers with a clear specialism, such as temporary works, drainage design, bridge assessment or BIM coordination, but it can make it harder to broaden your skills or step into leadership.
Permanent roles usually offer more structured development: mentoring, rotation across project types and support towards professional qualifications. If you are working towards chartership, it is generally easier to gather the breadth of experience and the supervision you need as an employee. Some contractors do achieve it, but it takes deliberate planning.
Likewise, if you hope to move into a senior management position such as associate or associate director, a long-term relationship with one firm usually counts for a great deal. Those roles involve business development, people management and commercial responsibility that firms rarely hand to someone on a fixed-term engagement.
Assess the market for your skills
Demand for contractors rises and falls with project cycles. When large programmes ramp up, clients often need extra capacity quickly, and contract opportunities multiply. When funding pauses or projects are delayed, contractors are usually the first to be released. Our overview of the UK infrastructure pipeline covers the sectors where longer-term demand looks most durable.
Ask yourself honestly how many organisations would hire you for a short engagement at short notice. If you can name several, and you have a network who know your work, contracting is far less risky than if you would be starting from scratch.
The practical side of running your own work
Contracting is partly a small-business decision. Depending on how you are engaged, you may need to handle:
- Insurance, including professional indemnity and public liability, which some clients specify as a condition of engagement.
- Accounts and tax returns, usually with the help of an accountant.
- Finding the next contract while delivering the current one, which takes time and energy.
- A financial buffer to cover gaps between contracts and the occasional late payment.
Some people enjoy that independence; others find it a distraction from the engineering they actually want to do.
Moving from contract back to permanent
The decision is not one-way. Plenty of engineers contract for a few years and then return to a staff role, often bringing valuable experience from a range of clients. If you are considering that move, be prepared to explain why you want permanence, and be realistic that the salary may look lower than your previous day rate even if the total value is comparable. Employers will usually be interested in what you learned on different projects and how you would apply it to their teams.
Questions to ask before you decide
- What is my realistic annual income in each option after costs, tax and unbilled days?
- How will this engagement be treated under IR35, and who decided?
- Do I need structured development or supervision for a qualification in the next few years?
- How would I cope financially with three months between contracts?
- Which option gives me more of the work I actually enjoy?
Answer those honestly, and take professional advice on the tax and legal points, and you are likely to make a decision you will still be comfortable with a few years from now.