The delay in making a decision is also designed to give both communities much-needed "breathing space" after a number of fights and arguments have recently broken out between pupils.
Council bosses had hoped to deal with the overcrowding problems at St Joseph's by swapping its building with the under-subscribed Broomhouse Primary, which shares a site with the school.
After opposition from Broomhouse parents, council bosses agreed to consider the alternative option of giving St Joseph's some extra classrooms in the Broomhouse infant wing – a proposal which parents from the Catholic school strongly objected to.
At a special meeting of the education committee held yesterday , Carol Munro, chair of the Broomhouse parent council, told of the "terrible" few weeks the school communities have suffered.
She said: "Fights have already taken place in school and in Sighthill Park. There are tensions between the two schools and the community at large.
"Parents are not able to even look at each other crossing the street. Kids have been calling each other names, there's been a few squabbles and fights.
"A year would certainly give us time to start bridge building."
City education leader Marilyne MacLaren said: "I realised very early on that this was a no-win situation. We do need time to settle down, calm down and find a way to talk to each other."
With both sides entitled to lodge a time-consuming legal appeal with Scottish ministers against either decision, education director Gillian Tee ruled that the "status quo" would have to be maintained in the meantime, regardless of any ruling taken by councillors. The primary one intake figures were therefore re-examined by officials to see if any short-term solution could be met to accommodate the pupil roll.
These showed a predicted intake of 47 P1s – not 56 as previously expected – that could be managed through team teaching and a composite class and would not require any extra accommodation.
Ms Tee came under fire from councillors for not producing these figures sooner.
Deputy council leader Steve Cardownie said: "Why was this exercise not undertaken irrespective of the threat of legal action?"
Green education spokeswoman Alison Johnstone added: "It simply beggars belief that we are expected to believe that full details regarding the number of catchment pupils expected to attend St Joseph's Primary School this August only became available (yesterday] morning."
Labour education spokesman Ricky Henderson added: "It's deeply ironic that the council has created this mess and are now asking the affected local communities to clear it up."