How to Choose a Work at Height Subcontractor? A Practical Checklist for General Contractors

A work-at-height subcontractor is usually a small piece of the overall schedule on a major construction project – but it’s one of those elements where a wrong choice of contractor generates a disproportionately large risk relative to the scale of the job itself. A fall from height on your site isn’t just the subcontractor’s problem – it means stopping work across the entire site, a National Labour Inspectorate (PIP) inspection, and difficult questions from the investor about why your vetting of the contractor wasn’t sufficient. Below is a checklist worth working through before signing a work-at-height subcontractor agreement – from verifying certificates, through insurance, to coordination with the rest of the crews on site.

Why Vetting a Work-at-Height Subcontractor Differs from the Standard Process

With most construction subcontracting, you verify experience, references, and price. With work at height, a fourth dimension comes into play: the probability of an accident and its consequences are incomparably higher than for ground-level work. This changes the hierarchy of selection criteria – price stops being the first filter you apply and becomes the last one, only after passing through the safety and formal-compliance screen described below.

It’s also worth remembering a key difference in liability – as the general contractor, you are usually the first party the investor’s claim is addressed to if something goes wrong, regardless of the fact that the work was physically carried out by the subcontractor. Only afterward, as a secondary step, do you pursue your own claims directly against the subcontractor. That’s an additional reason to treat subcontractor vetting as an investment in your own legal and financial security, not as a bureaucratic formality to tick off before work starts.

Step 1: Team Qualifications and Certification

Ask for a named list of the technicians assigned to the specific job, along with their certificates – IRATA or an equivalent system recognised in the industry. Check whether the team includes someone at supervisor level (L3 in the IRATA system), responsible for risk analysis, operation planning, and the safety of the whole team on site. You’ll find a detailed guide to the IRATA level system and a practical way to verify certificates in our article on the IRATA certificate.

Step 2: Liability Insurance With Cover Adequate to the Scale of the Project

A sum insured matched to the real value of the property surrounding the work, a clause covering liability for further subcontractors (if the company itself uses subcontractors), and an employer’s liability clause are the absolute minimum you should require from every candidate. We’ve listed the full set of specific questions to ask about policy scope in our article on liability insurance for a work-at-height company.

It’s also worth asking outright whether the subcontractor itself uses further subcontractors to carry out the work – if so, its policy needs to account for that, otherwise a gap in cover appears that you’ll only discover at the worst possible moment – when filing an actual claim. We’ve covered this topic in full, in the context of the liability chain typical of multi-tier construction subcontracting, in our article on liability insurance for a work-at-height subcontractor.

Step 3: A Site Visit Instead of a Ballpark Quote

A subcontractor who prices work without seeing the site either doesn’t understand the scale of the risk or deliberately overlooks it in order to offer a lower price and win the tender. A reliable work-at-height quote always starts with a site visit – assessing anchor points, access, surrounding conditions, and the stage the construction has reached. We describe what that process looks like in our article on quotations for rope access work and site visits.

Step 3b: OHS Coordination With Other Contractors on Site

On an active construction site, work at height almost never happens in isolation – other crews are operating in parallel, heavy equipment is moving around, material deliveries are underway. Article 208 of the Polish Labour Code imposes, in that situation, an obligation to mutually inform each other about hazards and to appoint an OHS coordinator whenever employees of different employers are working on the site at the same time. As the general contractor, you’re usually the one responsible for initiating this coordination – the work-at-height subcontractor should be brought into this process from the first day on site, not treated as a separate, standalone operation.

In practice, this means agreeing with the subcontractor on zones excluded for other crews during work at height, hours when rope work doesn’t conflict with crane operation or material transport, and a clear communication channel between the site manager and the person supervising the height-work team. A lack of such coordination is one of the first things the National Labour Inspectorate checks when inspecting a construction site where an incident involving several contractors at once has occurred.

Step 4: Matching the Method to the Construction Schedule

On an active construction site, rope access often beats scaffolding on time to start – the crew begins work without weeks spent waiting for a structure to be erected, which matters when the general contractor’s schedule is tight. It’s worth asking the subcontractor outright, though, whether the method they’re proposing actually fits the scope and stage of the work, and not just their own equipment capabilities.

It happens that a company equipped only with scaffolding recommends that method even where rope access would be faster, cheaper, and less invasive for other crews’ schedules – simply because it’s the only tool they have. It’s worth weighing the subcontractor’s recommendation against an independent assessment, especially for work on buildings with unusual geometry, where the difference in efficiency between the two methods tends to be particularly large.

Step 5: Documentation and Communication During Execution

A good work-at-height subcontractor provides, before entering the site: a safe work method statement (IBWR), confirmation that the team has been trained, and a communication plan with the site manager. The absence of these documents, or a dismissive “we’ll send that later” in answer to your question, is a signal to renegotiate the terms of cooperation before the crew actually sets foot on site and starts work.

What Onboarding a Subcontractor to the Site Looks Like – Step by Step

Beyond document verification alone, it’s worth having a standard process in place for onboarding every work-at-height subcontractor onto the site – so you’re not improvising it for every new job. A typical process includes: giving the subcontractor information about hazards specific to the current construction stage (active excavations, crane operation, other danger zones), jointly agreeing on zones and working hours with the other crews, reviewing access points and any restrictions arising from the progress of construction work, and a one-off induction briefing for the subcontractor’s team covering the specifics of that particular site.

This process doesn’t have to be time-consuming – with a well-prepared subcontractor who supplies complete documentation on their own (IBWR, certificates, policy), onboarding usually takes no more than a single coordination meeting before work starts. That investment of time pays off in a lower risk of misunderstandings and delays arising from mismatched schedules between different crews.

Common Mistakes General Contractors Make When Choosing a Subcontractor

• Treating work at height like any other subcontracting – applying the same standard selection criteria as for ground-level work, without accounting for the elevated risk and additional formal requirements.
• Choosing based on price alone, without analysing scope – comparing quotes that actually cover a different scope of safety measures and documentation as if they were identical.
• Failing to include the subcontractor in the site-wide OHS coordination – treating the height-work team as a separate, standalone operation instead of an integral part of the construction schedule.
• Leaving document verification until the last minute – accepting certificates and the policy literally on the day the crew enters the site, when there’s no longer time to clarify any gaps without delaying the entire project schedule.

Frequently Asked Questions

Is the general contractor liable for a work-at-height subcontractor’s accident?
Direct employer liability for worker safety rests with the subcontractor itself, but the general contractor, as the party coordinating the site, can be found jointly liable if it neglected the coordination duties arising from Article 208 of the Labour Code. We write more about this in our article on liability for a subcontractor’s accident.

How far ahead of the start of work should you begin vetting a work-at-height subcontractor?
The earlier, the better – ideally at the stage of planning the schedule for the whole project, not only once the deadline for a given stage is approaching. This allows for a calm, methodical comparison of several quotes and avoids the time pressure that almost always encourages skipping important verification steps.

Is it worth having a regular work-at-height subcontractor for all your projects?
Working with a single, proven subcontractor has measurable, practical advantages – the company gets to know the general contractor’s standards and procedures, which shortens the onboarding process for each subsequent construction project. It’s still worth keeping a list of alternative, vetted subcontractors, though, in case your main subcontractor doesn’t happen to be available at the required date.

6 Red Flags That Should Raise Your Guard

• A quote without a site visit – a figure given over the phone or by email alone, without any assessment of the site.
• No liability insurance policy number in the offer – a statement that “we’re insured” with no specifics you can actually verify.
• Inability to show certificates before signing the contract – certificates that “exist, but just aren’t to hand right now”.
• No defined team composition – an unknown number of people and their roles at the quotation stage.
• Pressure to sign quickly, with no time allowed to verify documents.
• A price noticeably below other offers for the same scope – this usually means one of the key safety-scope elements above is missing.

We cover all the warning signs to watch for when choosing a work-at-height contractor in more detail in our article on red flags when choosing a rope access company.

How to Compare Offers From Several Subcontractors at Once

When collecting offers from several work-at-height subcontractors, make sure every company is responding to an identical scope of inquiry – the same description of the site, the same stage of work, the same formal requirements. Without that, a price comparison loses its meaning, because differences may not stem from the contractor’s efficiency, but simply from one offer assuming a narrower safety scope than another. A good solution is to prepare a short brief containing all the elements from this checklist – certificates, insurance, schedule, required documentation – and send it in identical form to every potential subcontractor.

It’s also worth paying attention to how quickly and how specifically individual companies respond to the inquiry – the way a company communicates at the quotation stage often foreshadows how it will communicate during execution. A subcontractor who brushes off questions with vague answers right from the start, or pushes for a quick decision without allowing time for analysis, rarely changes that pattern once the contract is signed.

How We Do It

We start every job with a site visit, we hand over documents (certificates, liability insurance policy, IBWR) before entering the site, we agree the team composition and scope of liability in writing before signing the contract, and we choose the access method to match the actual geometry and stage of the building, not our own equipment limitations. If you’re planning the schedule for a project that includes a work-at-height stage, we’re happy to join the OHS coordination with the other crews on site before work even starts. Check out our full range of services or get in touch with us to discuss your specific project and construction schedule.