Engineering contractors span a huge range of specialisms (civil, mechanical, electrical, structural, process) and face specific IR35 and tax challenges that a generalist accountant will not know. Site-based working, public sector engagements and long infrastructure projects all create complexity that needs specialist handling.
Engineering contractors working on public sector infrastructure (Network Rail, Highways England, local authorities, NHS estates) have been subject to client-side IR35 determination since April 2017. Many received inside determinations without proper analysis of their actual working arrangements. If you are in public sector contracting, your status needs regular review as contracts and working practices change.
Site-based engineering work looks straightforward but the 24-month rule creates real complexity. Once a site qualifies as your permanent workplace (either because you have been there over 24 months or because it was expected at the outset that you would be), ordinary commuting costs are no longer allowable. We apply this correctly, including for multi-phase projects where the analysis is less obvious.
Specialist engineering skills (particular software expertise, specific sector knowledge, unusual certifications) can create a genuine substitution argument if properly documented. We help you understand whether your specialism supports an outside IR35 position, and what evidence is needed to demonstrate it.
Many engineering contractors work through framework agreements with large consultancies or directly with public sector bodies. The fee-payer and SDS arrangements in these structures are often poorly understood. We explain clearly who is responsible for what, and what your rights are if you disagree with a determination.
We review your contract against the three key tests with specific knowledge of how engineering roles typically work in practice. Site-based roles, framework placements and specialist project work each have different risk profiles.
We manage the 24-month rule correctly across your portfolio of site placements, making sure every allowable expense is claimed while nothing is included that would not survive HMRC scrutiny.
PSC accounts, CT600, Companies House filings and self assessment for you as a director. For engineering contractors with variable income across contracts, we also help with cash flow planning across the tax year.
“I had been on the same infrastructure project for 28 months. Nobody had flagged the 24-month rule to me. We corrected the travel claims and restructured the expense approach going forward. Should have spoken to a specialist two years earlier.”
Composite snapshot based on client patterns. Name and figures anonymised. The tax mechanics are real.
Book a free call. We will talk through your IR35 position, your structure and whether there is anything worth changing. No hard sell, no obligation.