Builders at Clifton-upon-Dunsmore first school in Rugby have been teaching the children about foundations, timber, and bricks.
The Warwickshire school has developed a special relationship with building contractors Tom Pettifer, and architects Corsphine and Wright, during the construction of a Pounds 600,000 extension.
Site manager Les Hardiman talks to the children every three weeks about how the extension is progressing, and brings building materials into the classroom to illustrate his talks.
The 150-pupil school was constructed in 1850 and the contractors are building the extension in the same Victorian style. The children were allowed to visit the building site to see the diggers at work, but when the scaffolding was erected they had to watch from behind a mesh barrier.
Headteacher Sandra Rossborough said: "It's a very good learning experience for the children. They've never got so close to diggers before."
Mr Hardiman said: "The children have asked really interesting questions - how many nails in the construction, how many tiles and why we had to dig foundations? I was amazed at how knowledgeable six and seven-year-olds were."
He has calculated that his colleagues have used 6,500 nails, but hopes to give the children an exact figure at the end of the contract.
As the building site is in the children's playground, safety was the subject of one of his first talks. He has also spoken about the impact of construction on the environment - for every tree cut down for construction, another one has to be planted.
The extension, which will transform the building into a seven-form entry primary school, will be completed in three weeks, and the children have already painted an underwater scene on one of the new classroom walls.
A time capsule in the extension's footings, containing photographs, newspapers, the Top 10 in the music charts, a tea towel depicting all the children, and a letter from the editor of the Rugby Advertiser will be opened in 50 years, when Mr Hardiman is 80.