Retrofit programmes move faster when evidence is captured once and organised for everyone who touches the file.
4.7/5 on Trustpilot · report and organised photos in the portal on completion · EPC by next morning in the standard flow. · 3 min read
Use this guide as a decision check, not as a generic reading page. The useful question is whether the evidence behind retrofit assessment (eco4): survey guide for installers is strong enough for an installer, designer, or homeowner to move to the next step without another round of avoidable questions.
For retrofit evidence, the weak point is usually not the headline requirement. It is the missing photo, document, measurement, or site note that stops the next person from trusting the job record.
A survey report should show what was seen, what was measured, what could not be accessed, and what still needs a design or installer decision. That keeps assumptions visible instead of hiding them inside a photo set.
The office, design, and install teams should be able to open the same report and understand the evidence path. If the page helps you spot what to ask for before survey day, it has done its job.
For a live project, pair this guidance with the sample report, deliverables, and guide price builder so the job is reviewed against the same standard Vertex uses for survey delivery.
The practical test is whether the page changes what happens next on a real property. If it helps your team ask for the right evidence, avoid a weak assumption, or brief the surveyor more clearly before the visit, it is supporting the job rather than adding another generic resource to the pile.