Human remains, archaeology and delays in a limestone delivery from France are being blamed for renovation work overrunning at Gloucester Cathedral.
Work on the outside of the building was due to be done in time for Christmas but will now finish next year.
Local traders say delays in the £6m project has put off visitors coming by coach.
However, project manager Anne Cranston said coach numbers were "up".
In March, it was reported work on the outside of the building would be completed by September.
Last month the team promised that it would be "done and dusted" by 3 December.
It has since been announced the work has been halted over Christmas and will not restart until January.
"We've not had so many tourists and business has fallen a little flat - not just for me but generally in the street," one local retailer said.
"So I'm a bit concerned about the deadline change."
However, Ms Cranstone said it was a "complicated" project that had been hampered by the discovery of "an awful lot of archaeology" and a "number of human remains".
"We've also used an awful lot of limestone but we can't get it from Painswick or Minchinhampton so it comes from the same seam from a quarry in France and unfortunately it has been delayed," she added.
"We've had a slight drop in our visitor figures - they've gone down by slightly less than 20 percent - but the number of people visiting on coach trips has gone up so the comments about coach drivers not wanting to come here is surprising."
She said she could not guarantee a completion date but it would be in the early new year.