West Ham need to make "substantial repairs" to their Upton Park home even if they confirm their move to the Olympic Stadium in nearby Stratford, a report has said.
The Hammers hope to relocate to the London 2012 stadium by the 2016-17 season - but their current home requires major work to tackle corrosion, documents seen by the Guardian have revealed.
A report by the Newham Council-run West Ham safety advisory group show that "concern [has been] expressed" about the state of parts of Upton Park and major works would have to be undertaken before 2015.
Although there is no suggestion the problems would affect fan safety, they mean the east London club would need to carry out work before 2016-17, with further major repairs needed if they ended up staying at Upton Park.
The report says there is a need for "essential works [to solve problems] such as the rust in the steelwork which is, at the moment, just surface corrosion but if not treated will get worse".
David Grant, Newham's principal licensing officer, told the West Ham safety advisory group that "if the [Olympic Stadium] deal does not go through, extensive work would need doing".
West Ham are waiting for the London Legacy Development Corporation to finalise approval for their move to Stratford, but several other agreements still remain to be concluded before they can begin planning a relocation.
West Ham officials told the Guardian that maintenance work was on hold while they waited for the Olympic Stadium go-ahead and said it was the sort of work needed at football grounds every decade or so.