Pemberton Centre work cost £400,000 more than estimated
Work to improve a council leisure centre cost £400,000 more than expected because the initial estimate was "not robust enough", a report has found.
East Northamptonshire Council agreed last year to refurbish the Pemberton Centre in Rushden at a cost of £1.2m, but the figure later rose to £1.6m.
A council working party found the initial estimate had not taken into account all the work that was needed.
The council said it had adopted the report's recommendations.
The original estimate was obtained as part of an "invest to save" study of the council's leisure facilities, but the total cost subsequently changed five times.
The working party set up to examine why it fell so far short said the £5,000 budget for the study was "clearly not sufficient to provide a robust estimate".
It did not take into account the additional costs of moving the heating and air conditioning and of providing a project manager, quantity survey or clerk of works.
The working party made seven recommendations and in a statement, a council spokeswoman said the authority reviewed its "processes in a transparent way so that we learn from them".
She added: "Normal services at the Pemberton Centre will resume as planned during November and the centre has remained open throughout the work."