Essex County Council has said the John Ray Infant School in Braintree will not be open next week after it was destroyed by fire.
Councillors have met to decide on temporary accommodation for the school as soon possible. However, the school will not be able to open on Tuesday September 3 as planned.
Cllr Ray Gooding, Cabinet Member for Education and Lifelong Learning, said: "I am very sad for the community as this very fine school has lost its building.
"The school has excellent leadership and I have every confidence that once we can arrange temporary accommodation they will continue to provide very good education.
"I am also immediately looking into plans for a properly rebuilt school and will be working with the school leadership on this."