The toughest terrain isn't greenfield construction, but a building still in use: with extensions, additional storeys and renovations, the work goes on right next to the client's existing property – often inside it. CAR's base cover protects the works under construction; protecting the existing building is a separate extension. This article explains why that's the most important extension on any project that isn't on a greenfield site.
- Existing property cover protects the already-standing part of the building affected by the works against loss arising from the construction activity.
- Demolition, underpinning, chasing, tie-ins to building services, and opening up the roof – the typical sources of hazard.
- Leaving out this extension is the most common and the most costly inception mistake on renovation projects.
- A condition survey before work starts is claim-settlement's best friend.
Why isn't the base cover enough?
Because the subject of the base cover is the contract works – what you're building. If the existing floor slab cracks while an extra storey is added, or the lower floors flood during a tie-in to the building services, that's not a loss to the works under construction but to the existing building. This typically falls under the existing property extension – if that's missing, at most the contractor's business liability insurance might respond, with its own limits and exclusions. (If the damaged building is not the client's, but belongs to an outside party – the neighbour, for instance – that's already a matter for the liability section.)
Typical situations
Adding an extra storey: underneath the opened-up roof sits the occupied house – a single downpour can damage three floors. A working office building's interior renovation: live building services, a server room and tenants' equipment sit right next to the work area. Basement lowering, underpinning: the stability of the existing structure is what's at stake. Facade renovation: scaffolded work affects the windows and doors, the cladding, the building services. What they all have in common: the biggest risk isn't what you're building, but what's already standing there.
What is worth watching for with this extension?
First, the sum: existing property cover works with its own limit – it should match the realistic value of the affected part of the building. Second, the scope: exactly what counts as property "affected by the works" – only the adjoining rooms, or the whole building? Third, the expectations: the wording typically calls for protective and technical care (temporary covering, dust protection, phasing). And fourth: a condition survey before work starts – photos, video, a written record – because that's what decides a dispute: documentation article.
Whose interest is it?
Primarily the client's – it's their property at stake – but the contractor's too: an unresolved existing-property question is the fastest route to a project dispute. As a principal, this is therefore the first thing to check on the contractor's policy: principal's checklist. For listed and older buildings, there's an extra layer on top: separate rules.
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