Pupils donned hard hats as they took a closer look at how their school is being expanded to meet the growing demand for primary places.
Eight new classrooms are being built at The Blue School CE, in North Street, Isleworth, where the library, technology suite and playground are also being renovated.
Pupils were joined by Isleworth councillor Sue Sampson as they saw for themselves how work was progressing during a guided tour earlier this month.
The new rooms, which are due to be ready in time for the beginning of the autumn term this year, mark the latest stage in the school's expansion to two-form entry.
It first admitted 60 pupils into its reception class in September 2012 and opened two new classrooms last September.
Jon Frostick, headteacher of The Blue School, said: "The substantial building works have not had an adverse effect on the children's learning; indeed we have used the project as an opportunity for them to learn about construction projects. We are thrilled with the progress to date and look forward to seeing the end result."