The Duchess of Cambridge, whose visit on 23 April will still go ahead, had been due to see the playground and climbing frame, known as 'The Fort', which was destroyed in the fire.
Local residents and businesses, as well as staff at The Willows Primary School, are standing up against the deliberate blaze and plan to rebuild the playground in time for the royal visit.
"We're determined to rebuild the fort with the help of the local community and others," said head teacher Ann Whitehead. "And have had offers already from companies wanting to help us with this."
"We were all devastated when we heard about the fire," she added. "But we're not going to let them beat us."
Three boys, all aged 13, have been arrested on suspicion of arson in response to the fire.
Kate's attendance at Willows Primary will be closely followed by her visit to the National Portrait Gallery on 24 April and a newly announced trip to the Warner Brothers Studios.
The Duchess will be joined by husband Prince William and her brother-in-law Prince Harry as the trio enjoy a tour of the Harry Potter set. William, Kate and Harry will journey to the studios in Leavesden, Watford where they will meet some of the creative teams behind several recent Warner Brothers productions as well as some of the props and costumes.
Prince William will then give a short speech before the three host a meeting for their Charities Forum.