Who bears the cost of concealed conditions found during A&A works?
Whoever the contract says. If the contract is silent, the contractor that priced a lump sum after inspecting the site may be taken to have accepted much of the risk, but disputes are common. Standard forms vary: PSSCOC's adverse physical conditions clause addresses sub-surface works. For A&A works, allocate concealed-condition risk expressly, and consider opening-up or survey work before tender.
From the RRD Field Guide, checked against the sources cited in Variation Orders and Provisional Sums: How to Stop Surprise VOs on Singapore Building Works. General information, not advice for your project.
The fuller picture
Surprise variation orders usually come from scope that was never fully defined, items excluded from the quote, provisional sums used as placeholders, and concealed site conditions. Owners reduce them by defining scope in drawings and an itemised schedule, pricing exclusions when comparing quotes, requiring written instructions and quotations before varied work starts, and agreeing valuation rules in the contract.
More questions on this topic
- What is a variation order?
- What is the difference between a provisional sum and a prime cost sum?
- Is a lump-sum quotation fixed no matter what?
- Can a contractor claim for variations done on verbal instructions?
- How are variations valued?
- What are dayworks?
- How should I compare quotations with different exclusions?