Costain is suing defunct engineering consultant Haswell for more than £3.5 million after claiming it botched the groundwork designs for two water treatment plants at Bolton.
Haswell was taken over by Severn Trent in 1990 but ceased trading two years ago. The staff were then transferred across to the utility giant.
In the writ, filed at the Technology & Construction Court in London, Costain says the firm failed to “act with reasonable skill and care” when advising on the new works at Lostock and new sludge treatment plant and potable water pumping station at Rivington for United Utilities.
In addition to the multi-million pound claim, Costain is suing its former contractor for interest, damages and costs.
In the writ Costain says: “The claim concerns the defective design of the ground treatment works.”
It alleges Haswell recommended it undertake a preloading scheme on the sites prior to construction which started in 2002.
But Costain says this had not taken into account the high silt and clay contents detected in an earlier ground report “and accordingly failed”.
It says: "A civil engineer acting with reasonable care and skill would have concluded from the (report) that post-construction creep was unlikely to be small given the presence of the compressible clayey silts in the ground.
"Haswell failed to act with reasonable care and skill when it advised Costain that preloading was an appropriate treatment for the ground."
It adds that at pre-tender stage Haswell did not say piling work would be needed to be carried out and as result could not bill United Utilities because piling had not been included in the original contract.
The court papers say: “If Haswell had acted with reasonable care and skill at the pre-tender stage, Haswell would have advised Costain that the ground… would have to be piled.
“Costain would have prepared its tender in accordance with this advice and would have… been paid the cost of piling by United Utilities.”
It alleges Haswell’s failure to outline all necessary works – which also included the installation of a drainage blanket – and tests pre-tender delayed the project by 12.8 weeks. Therefore the claim also includes prolonged site overheads and increased inflation costs.
In addition Costain hopes to recover £462,000 it was required to pay to water treatment specialist Ondeo Degremont, which had sued the main contractor for delays and disruption to the project.
Severn Trent was unavailable for comment.