Work to address concerns about potentially dangerous concrete at Forres Academy is expected to take up to four weeks.
Contractors arrived at the school this week after RAAC (reinforced autoclaved concrete) was found in the building.
The material has caused concerns across the UK after the roof of a primary school in England collapsed.
Urgent work is now taking place across the country to avoid similar incidents.
What work is being done at Forres Academy?
A survey from external structural engineers commissioned by Moray Council reported RAAC concrete was in a “small number” of classrooms at Forres Academy.
Since the summer holidays the science and art corridors have been closed while assessments are done.
A letter from the council’s head of education, Vivienne Cross, and head of property, Edward Thomas, has now been sent to parents to explain the safety of pupils and staff and continuity of education is the main focus.
They wrote: “The work is ongoing. However, the contractors are mindful of noise levels and are working with the school to consider the best time to undertake certain aspects of the work so as not to disrupt learning.
“We expect the work to take around four weeks and classrooms will be brought back
into use as they are completed.
“The council continues to follow current guidance and best practice issued by the Institution of Structural Engineers and the Scottish Government, which means only closing areas of high risk.”
What is RAAC concrete latest?
Councils, NHS boards and countless public and private agencies have been carrying out urgent surveys after RAAC concrete concerns were raised in recent weeks.
The material was used in construction from the 1950s to the 1990s and is less durable than reinforced concrete.
It is estimated it has a life expectancy of about 30 years, meaning many buildings with it could be at risk of safety concerns.
The roof of a primary school in Kent in 2018 collapsed just 24 hours after signs of stress began to appear.
The Scottish Government has now confirmed 40 schools, including Forres Academy, are known to contain RAAC concrete.
Deputy First Minister Shona Robison has written to the UK Government to request additional funding to cover repairs.