The Nottingham-based firm recently handed over the 420-place New Lubbesthorpe Primary Academy at New Lubbesthorpe in Blaby, Leicestershire.
Clegg Construction invited children and families from the local community to bury the time capsule at the site to mark the opening of the school.
The new school, designed by GSS Architecture, accommodates children aged 4-11 and is the first school to be completed on the new large-scale residential development in West Leicestershire. It was handed over to Leicestershire County Council which has appointed the OWLS Academy Trust to run it.