‘How do we price work on boggy ground?’

We’ve been asked to price a job in an area where there’s notoriously soft, boggy and waterlogged ground. Should we try to adjust the contract to allow for the risks of poor ground conditions and how much should we allow?

For jobs in areas prone to boggy, soft ground and waterlogging, it is vital to adjust to mitigate the risk and any exposure due to unknown costs at the earliest possible opportunity.

Unamended forms place all unforeseeable ground risk on the contractor. They assume the contractor has had the opportunity to conduct pre-contract site investigations. This highlights the importance of identifying any potential issues as soon as possible.

In 2024, the JCT forms included relief for unexploded ordnance and asbestos, but are still largely silent on ground conditions. Therefore, if you sign an unamended contract and encounter boggy ground or a high-water table, you cannot claim extra money or time. Unrecoverable costs will directly impact your margin.

To mitigate this, consider introducing a schedule of amendments, to transfer the risk back toward the employer. Such a schedule should treat unforeseeable adverse ground as a “relevant event” – to have entitlement for an extension of time – and a “relevant matter” – to claim additional direct loss and expense for remedies such as temporary works, pumping, piling.

It is unlikely that an employer would accept such an open risk for the ground conditions, which is where a geotechnical baseline clause could be agreed.

Under such a mechanism, you agree that you are responsible for the ground conditions only up to a specific, agreed baseline from the known information and incorporated into the contract. This could be based on the anticipated water table depth or the soil bearing capacity for example.

With these parameters in case, you can price what you know, but also if the ground turns out to be worse than what is stated, the contractor would be entitled to additional cost or time.

In contrast to the JCT suite of contracts, NEC explicitly allocates physical conditions risks. It identifies that a physical condition is a “compensation event” (CE) if it is something an experienced contractor would judge to have had such a small chance of occurring that it would have been unreasonable to allow for it.

It is essential to review the “site information” provided by the employer in detail. This is the benchmark for a CE. You are contractually assumed to have interpreted the site information using your experience.

If the physical conditions encountered are something an experienced contractor would not have reasonably foreseen at the contract date, then this can generally be claimed as a CE.

Pricing a job on soft, waterlogged ground requires converting unknown physical risks into quantifiable items. Though there is no specific way to price for ground uncertainty with every project being different, some measures can be broadly applied.

Firstly, try to avoid broad assumptions and pricing “blind”. If the employer has not provided an intrusive ground investigation report, formally request it and do not enter into a contract without one. Dependent on the level of perceived risk, with a specialist’s advice you should determine what tests and reports are applicable.

Make specific and informed allowances for dewatering and temporary works. If the water table is high, a dewatering system must be in place to allow works. Soft ground limits standard machinery access.

This in turn will impact construction and delivery of materials. Within your price, allow for enhanced haul roads and piling mats. Increased costs for safety measures regarding reinforced trench support must also be accounted for.

Pricing a job in boggy and waterlogged conditions without contractual protection is a high-risk strategy that can have severe cost consequences.

Under an unamended JCT contract, the financial and timeline liabilities sit entirely with you, whereas the NEC framework provides a structured mechanism for relief through CEs, provided the risks were truly unforeseeable based on the site information.

Importantly, to safeguard you must price each project individually. Do not price blind and use the specific site information to mitigate the potential extraordinary costs.

Ultimately, your best commercial defence is to negotiate clear contractual baselines and limits from the start ensuring that once the ground conditions cross a known defined threshold of severity, the risk and cost transfer back to the employer.

Mark Roskell is senior consultant at Decipher.