The major investment will deliver additional and enhanced facilities for the school, which provides primary and secondary education for young people with complex needs from across West Lothian.
The scale of the works includes demolition of the original block, construction of a new extension comprising a games hall, dining, office accommodation and additional classrooms.
It also includes improved vehicular access from Elm Grove and enhanced car parking with 66 vehicle spaces, disabled parking bays, day-time visitor parking and improved drop-off and pick-up zones. Arrangements have been made for staff to use additional parking at the nearby Blackburn and Seafield Church to minimise disruption while the work is ongoing.
This is the third extension to Pinewood in the last 12 years, and will be open in 2022 as part of a £26.5 million investment programme in schools for pupils with additional support needs.
Executive councillor for education David Dodds said: "It's fantastic that work will soon start on the £5.8 million extension to Pinewood School in Blackburn.
"It will deliver first-class facilities for many of our young learners with complex needs for many years to come.
"West Lothian already has one of the best learning estates in the county and this extension as part of the wider £26.5 million in schools for pupils with additional support needs will ensure this going forward."
Hub South East is delivering the new facility on behalf of the council, with BAM Construction appointed as the main contractor.
Roddy Clark, Hub South East's Operations Director, said: "We're delighted to have reached the milestone of starting construction on the new Pinewood School.
"Delivering this important investment in education for West Lothian Council will make a real difference to young learners with severe and complex needs and we look forward to making the plans for a progressive new learning space in Blackburn, a reality.
"We're also committed to ensuring that during construction, local people and SMEs benefit from a range of opportunities. From new jobs and work placements, to apprenticeships and curriculum support, this project will support both individuals and businesses and will result in increased social value for West Lothian, further promoting Hub's commitment to local community benefits."
Martin Cooper, BAM's Construction Director, said: "We will bring our vast experience in school building, our collaborative approach, and our community-minded people to bear on these new facilities which will help transform so many lives in years to come.
"As a result of this scheme staff and pupils will benefit from a more sustainable and purpose-built environment to teach and learn in that will help provide better outcomes."