From 4:30 -7:30pm, The Bletchington Bash will see the grounds transform into an outdoor market set up for food and craft stalls, as well as children's activities. 

Principal Craig Booth will once again put himself up for a public pool dunk, in the hopes of boosting the fundraising tally which will go towards extensions to the school hall.

Mr Booth said the Parents and Citisens' Association event was the major contributor towards the school's aim of raising $10,000 a term, for the $400,000 hall upgrade.

"So if you want to see the principle dunked, you got to pay up," he said.

Built to fit around 500 children nine years ago, the school hall has been under utilised since enrolments have swelled to around 670 children.

The school has been tasked with raising half of the cost to have an extension to the hall, which would create extra space for band rehearsals and school assemblies.

Mr Booth said the "P and C" have raised around $100,000 so far and the school has contributed around $50,000.

A visit from the fire brigade, jumping castles and other children's activities are expected to add to that tally on Friday.