How much does it cost to build a safe and secure tree house for the kids?
I think it mostly depends on the material used and also the house plan.
My neighbor recently got a play room made for his sons, it more of a granny flat not a tree house exactly. Anyway it cost him around 1.2 k approx for the two room house, but said it was furnished and upgraded according to the needs of his sons.
I am sorry I could not get the answer to the query you asked, but hope this helps.
For more design ideas, have a look at - http://grannyflatsolutions.com.au/
Search the TrustedPros directory and discover the best contractors in your area.Find your home service pro