Private Sector IR35 Guide for Architecture Employers

Private-sector IR35 affects architecture employers when a contractor supplies services through an intermediary, such as a personal service company, and the client has to decide how the off-payroll working rules apply.

This is not tax advice. Start with GOV.UK off-payroll working guidance for clients, then get specialist advice where the risk or value of the assignment is material.

First decide whether the client rules apply

GOV.UK says the off-payroll rules apply to all public-sector clients and medium or large private and voluntary-sector clients. Small private-sector clients are treated differently, so the client-size question comes first.

For architecture practices, this matters because two contractor briefs can look similar on the surface but sit in different tax responsibility routes depending on who the client is and how the assignment is structured.

Listen: running an architecture practice is not simple

This related Architecture Social episode adds broader practice-leadership context around risk, operations and the commercial reality behind decisions.

What employers should settle before briefing

• Is the client small, medium or large for off-payroll purposes?
• Who is making the employment status determination?
• Will a Status Determination Statement be issued?
• Who is the fee payer in the chain?
• Is the role inside or outside IR35?
• What working practices are expected day to day?
• How will disputes about status be handled?

What an architecture brief should say clearly

A good contractor brief does more than list software and project type. It should describe the working reality that sits behind the IR35 decision.

• Whether the contractor is filling a defined project need or covering a permanent staff gap.
• Who controls the order, method and hours of work.
• Whether substitution is realistic in practice.
• Whether the contractor supplies their own tools, insurance or specialist method.
• How integrated the contractor will be with the internal team.
• What happens if the project scope changes.

Reasonable care is not a box tick

Reasonable care means looking at the real assignment, not just the job title. A contractor brought in to deliver a defined package is different from someone filling a permanent staff gap under close supervision.

• Use the Check Employment Status for Tax tool as one input, not as a replacement for understanding the work.
• Read the GOV.UK contractor and intermediary guidance for medium and large clients.
• Keep GOV.UK’s off-payroll working collection as the current guidance hub.

Architecture examples that need care

• A BIM contractor embedded five days a week in one studio team.
• A project architect covering a staff vacancy for several months.
• A consultant delivering a specific planning package with their own method.
• A technical specialist working across multiple clients.
• A contractor whose role changes halfway through the assignment.

None of those examples decides the status by itself. The point is that architecture work can blur between consultancy, project delivery and staff augmentation. That is exactly why the brief, determination and working practice need to match.

Communication with contractors matters

Contractors will judge the opportunity partly on how clear the practice is. If the status, payment route and working practices are uncertain, good contractors may walk away or price the risk into the rate.

That does not mean every inside-IR35 role is unworkable. It means the employer should be honest early, especially where umbrella employment, payroll deductions, employer costs or rate negotiation are involved.

Common mistakes

• Using one IR35 decision for very different assignments.
• Writing a contractor brief that reads like a permanent job advert.
• Treating status as an agency-only issue when the client has responsibilities.
• Forgetting to update the status thinking when the role changes.
• Letting the contractor discover the payment route after offer stage.

Architecture Social view

Stephen’s recruiter view is that clean briefs prevent messy negotiations. If a practice wants good contractors, it needs to explain the project, route and risk clearly enough for the contractor to make a sensible decision.

Next step

Before advertising a contractor assignment, write the working practices, decision-maker, fee-payer route and status position into the brief. For the worker-side view, read the private-sector IR35 contractor guide.