KZ: Hi Andy! We have loved the entire Treehouse book series, and The 169-Storey Treehouse is an epic conclusion to the adventure! Why did you decide to do a zoom out ending?

A: It was a last minute thing, one last cherry on top. They're all living happily ever after and I love that we got Jill into the Treehouse finally. I would have loved to put her in right from the start, but I liked that she had her own life. As the series has gone on, she's become a crowd-favourite and had more of a role in each book. It felt mean to not have her there, and the storm blowing her house away was the perfect reason.

KZ: Did you have many different ideas for how to end the final book?

A: I think the original ending was just a happy ‘there's no treehouse like home’. I do love zoom out endings. It’s something that we haven't done in any other book, so we put everything into the last one. How the series ends really affects how you perceive the whole adventure. It was just so poetic a dream to have 13 books, because we started with 13 levels and 13 chapters for every book.

KZ: How did the number 13 become important, and how did it feel to end the series?

A: When I told everyone, there was a moment of sadness but everyone also thought this was the perfect place to end. We wrote The 13-Storey Treehouse without the idea that it would be a series, but when the response from the kids was so strong, we said we would do another book. We discussed whether we would add one more storey, so it was the 14th Storey, and the 15th Storey, but that seemed a bit mean, so we decided to double it. So we just went with thirteens, and that's an accidental amount of flaws that Terry happened to draw, and it became like a law in the treehouse.

Want to read the full interview with Andy Griffiths? Grab the November 2023 ‘Spooky Battle Royale’ issue of K-Zone, on sale now!

Want more Treehouse? Check out these throwback K-Zone interviews with Andy Griffiths in 2014, and Andy Griffiths and Terry Denton in 2015!