Council Executive voted to continue to progress a preferred option for St Kentigern's, that would see the parts of the school affected by reinforced autoclaved aerated concrete (RAAC) roof planks demolished and a new wing constructed in the same location.
A further £10 million has been allocated towards delivering this three-year project, taking the total funding commitment by the council to £20.2 million.
This leaves £10 million outstanding, and it was agreed to approach the Scottish Government for financial support for the remaining funding required to deliver the project, as further borrowing would negatively impact on the budget available for education in West Lothian.
Design work will continue over the summer, with the aim of a further report back to committee in Autumn 2023 to give final approval for the project, if additional funding can be secured.
Executive councillor for education Andrew McGuire said: "It's a hugely challenging situation at St Kentigern's, and I'd like to thank everyone involved for their hard work to get us to this stage.
"We believe that the £30 million proposal to replace the parts of the school affected by RAAC represents the best option to secure the long-term future for St Kentigern's. The new build replacement wing would provide an opportunity to deliver the best possible environment for modern education.
"Unfortunately, the huge pressures on council finances at this time means we are unable to deliver such a large-scale project within current resources, without impacting on other budgets within education.
"We will be approaching the Scottish Government to ask for their support to identify potential funding for the remaining £10 million required to deliver the project and a positive long-term future for St Kentigern's."
An additional £300,000 was also allocated to maintain the temporary units at the school for a further year to provide the additional classroom space necessary in the short-term.