What is a site survey?
A site survey measures and assesses a building before a contract is priced — areas, surfaces, layout, access, hours and constraints. It is what a specification and a labour model are built from.
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<img src="https://cleanoptix.co.uk/glossary/site-survey/diagram.svg" alt="site survey — diagram from CleanOptix" width="880" height="620" loading="lazy">
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<a href="https://cleanoptix.co.uk/glossary/site-survey">What is a site survey?</a> — diagram by
<a href="https://cleanoptix.co.uk">CleanOptix</a>
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</figure>Pricing without one is guessing. Area from a floor plan misses the layout, the surface types, the furniture density and the access restrictions that determine how long the work actually takes.
It is also where the awkward constraints surface: no access before a certain hour, a lift shared with deliveries, a site with no water on one floor. Each of those changes the hours required.
Surveying at the same time of day the work will happen is worth the inconvenience, because a building at six in the morning is not the building at eleven.
In practice
A price built from a floor plan and a phone call.
The plan does not show that the loading bay is cleaned, that there are three external smoking shelters, or that the building has a basement archive nobody mentioned.
Every one of those appears in month one as an expectation, and the contractor either absorbs them or starts the relationship with a variation.
The hour spent walking the building is the cheapest hour in the contract.
What goes wrong in practice
- Areas taken from drawings rather than measured.
- Surveyed during the day for a contract that will be delivered at night.
- Constraints noted in a report but never reflected in the labour model.