Introduction
One of the most common sources of stress in residential building projects isn't poor craftsmanship or bad communication — it's unexpected discoveries. The wall that turns out to be load-bearing. The drain that's in the wrong place. The rotting timbers discovered when the loft floor is opened up. The asbestos found during the strip-out. Unexpected issues are genuinely unpredictable — and they happen on most significant building projects at some point. The difference between a project that handles them well and one that doesn't usually comes down to three things: how the contractor communicates when they discover the issue, how the contract handles variations, and how the client responds.
How a Good Contractor Communicates Unexpected Issues
When an unexpected issue is discovered on site, a professional contractor should: stop the affected work immediately if proceeding could cause further damage or create a safety risk; document the discovery with photos before anything is disturbed; notify the client clearly and promptly — what was found, where, and what the implications appear to be; present the options for how to proceed, including the cost and programme implications of each; and wait for client instruction before proceeding where the issue involves significant additional cost. A contractor who proceeds without telling you, or who presents a significant variation invoice at the end of the project without prior discussion, is not handling the process correctly.
The Importance of the Variation Process
Most construction contracts include a variation procedure — a mechanism for agreeing changes to the original scope, including changes driven by unexpected discoveries. A proper variation process involves: the issue being identified and communicated; the contractor providing a written assessment of options and costs; the client approving in writing; the agreed additional work being carried out; and the variation being added to the running cost account. If you're not operating within a written contract with a variation procedure, this process becomes a matter of good faith rather than contractual obligation — one of many reasons why having a proper written contract matters.
Common Unexpected Discoveries on London Building Projects
Rotting or inadequately sized roof timbers — particularly common on Victorian and Edwardian properties, discovered when a loft conversion opens up the existing roof structure. Hidden chimneys or structural elements — chimney breasts plastered over or supporting walls not obvious from the drawings, revealed during strip-out. Asbestos — properties built before 2000 may contain asbestos in artex ceilings, pipe lagging, roofing felt, or floor tiles. If asbestos is suspected, work must stop and a survey carried out before proceeding; removal requires licensed contractors. Drainage in unexpected positions — drains found in different locations from what was assumed in the design, affecting foundation positioning. Poor existing workmanship — previous extensions or alterations done without Building Regulations approval, revealed during the project.
How Clients Should Respond
When an unexpected issue arises, the client's role is to stay calm and focus on the decision at hand, not the disruption; ask for the options to be clearly explained before agreeing to anything; request a written variation proposal with the cost broken down; refer to the contingency you held back for exactly this purpose; and make a decision within a reasonable timeframe to avoid compounding the delay. An unexpected issue is not, in most cases, evidence of a contractor cutting corners or deceiving you — it's usually evidence that the condition of an old building is imperfectly known until it's opened up. RCB Design & Build manages unexpected discoveries professionally — with clear communication, written variation proposals, and client-led decision-making before any additional work proceeds. Contact us to discuss your project.