Waste discovered in the subsoil during the course of the works – contractual and administrative risks on the part of the Contractor

In the case of major infrastructure projects, it sometimes happens that rubbish is uncovered in the subsoil during earthworks: rubble and construction waste, but also household waste, packaging, scrap metal and end-of-life equipment – material not anticipated in the documentation provided to the Contractor. On site, this is a technical and logistical issue: provide skips, remove the waste, and get back on schedule. In reality, however, it follows two parallel paths – the contractual and the administrative – each with its own assessment criteria and deadlines, and neither of which determines the outcome of the other. This distinction determines whether the Contractor will be reimbursed for the time and costs incurred, or whether they will have to bear them themselves.  

The contractual framework is based on Sub-Clause 4.12 of the FIDIC Conditions. The definition of ‘physical conditions’ is broad: it covers natural and man-made conditions, physical obstacles and contamination, including subsurface conditions. Material buried in the ground falls well within this definition; consequently, disputes rarely concern the classification of the phenomenon itself. The dispute centres on its assessment – namely, whether the conditions encountered were Unforeseeable, that is, rationally impossible for an experienced contractor to have foreseen by the Reference Date.  

The procedure is concise and time-bound. The Contractor shall submit a notice within the time limit specified in the Contract Conditions, and sufficiently in advance to enable the Engineer to carry out an inspection before the conditions are disrupted. The notice shall describe the conditions encountered, state the reasons why the Contractor considers them to be Unforeseeable, and set out their impact on the progress of the works and on the Cost. The Engineer shall inspect and examine the conditions and may then issue instructions which the Contractor shall comply with. Throughout this period, the Contractor remains obliged to continue carrying out the Works – the Contractor is not entitled to suspend the works.

The entitlement arising from this route covers an extension of the Time to Complete and the Cost, but not the Cost Plus Profit. The assessment of Unforeseeability is, in this regard, a matter of degree: the Engineer determines whether, and to what extent, the conditions were Unforeseeable, and partial acceptance of the claim is the norm in this matter, not the exception. Furthermore, this entitlement does not arise automatically – it requires the claims procedure under Clause 20 to be followed, with its own time limits for notifying the claim and for submitting a full, detailed claim. In public contracts, these time limits are often modified by the Special Conditions and are treated as strict deadlines; consequently, failure to meet them precludes the right to claim, regardless of the merits of the claim. These time limits run from the discovery of the defect, not from the moment the problem becomes costly, and an informal report – such as an entry in the site log or information provided during a meeting – rarely meets the substantive requirements for notification.

In practice, however, the burden of justification remains decisive. Contract documents usually place the onus on the Contractor to interpret the data provided and assume that the Contractor has ascertained the subsurface conditions; indeed, the responsibility for identifying these conditions to the extent required for the agreed solutions is often explicitly assigned to the Contractor – particularly where the Contractor is also responsible for the design. The absence of information in the documentation does not, therefore, constitute an assurance by the Client that the material is not present in the subsoil. This is because subsoil investigations are, by their very nature, limited to specific points. A claim based solely on the argument that ‘this was not mentioned in the documentation’ is therefore weak – it must demonstrate the scale and nature of the phenomenon as exceeding what an experienced contractor could reasonably have assumed at the tendering stage, as the assessment here is quantitative, not merely qualitative.

Regardless of the dispute over ‘unforeseeability’, the material itself must be removed, and this opens up an administrative process in which the Contractor assumes a role that it usually fails to recognise. Pursuant to Article 3(1)(32) of the Waste Act of 14 December 2012, the producer of waste arising from the provision of construction, demolition and renovation services is the entity providing the service, unless the contract provides otherwise. The entity removing the backfilled material therefore becomes the producer of that waste, along with the full range of record-keeping and reporting obligations, as well as the obligation to transfer it exclusively to an entity holding the required permit. At the same time, Article 3(1)(19) of this Act introduces a presumption that the holder of waste located on a property is the person in control of the land, whilst Article 26(1) imposes on the holder the obligation to remove waste without delay from a place not designated for its disposal or storage – provided that this presumption may be rebutted by demonstrating who actually left the waste there.

Hence a conclusion that runs counter to conventional construction wisdom: material should not be removed before the condition has been documented. Hasty removal destroys evidence of the scale and nature of the phenomenon – precisely what a claim must be based on – whilst at the same time casting the Contractor in the role of a waste producer without any compensation in return. Particular caution is required where hazardous waste is suspected, as this alters both the procedural framework and the cost of waste management.

Therefore, a contractor who comes across such material should ensure three things are in place, even before deciding whether to remove it.

Firstly, establish the facts: dated photographic evidence, measurements of the extent of the damage, excavations and samples. This serves both as evidence to support a claim and as proof of the nature of the material; and, when the assessment is quantitative, documenting the extent of the damage can be decisive for the outcome.

Secondly, establish the actual deadlines and substantive requirements applicable under the contract in question – both for the notice under Sub-Clause 4.12 and for the notice of claim and the full, detailed claim. This is because the content of the notice defines the scope of the future claim, whilst strict deadlines determine whether a claim can be settled at all.

Thirdly, keep separate records of costs from day one: quantity surveys, documents confirming waste management, invoices, and the labour and equipment requirements. Reconstructing this data once the work is complete is always more difficult and less reliable than documenting it as you go along.

In practice, each such case requires individual analysis based on both the Contract Terms following specific amendments and the waste regulations. The sooner these two approaches are aligned, the lower the risk of a situation arising in which the Contractor correctly fulfils its statutory obligations but, at the same time, loses the opportunity to claim reimbursement for the costs incurred.