how to build a treehouse?

I want to build a treehouse for my kids, well actually not a real treehouse a little house just for them, but with that style.

Start here: stilesdesigns.com
Any of their books is a good clearly-written beginning for thinking and planning treehouses, playhouses, and even raft houses.
For example, we redesigned one of their raft houses into a strong, lightweight, lovely treehouse 20 feet up in our redwood clump. One of these days we'll get around to instructablizing it.
Meanwhile, trust the Stiles people.
Also, keep your eyes open for free doors, windows, plywood and other wood from local home remodels, yard sales, and Craigslist.
We built most of our treehouse from free recycled wood. And great old doors and windows with lots of character, too.
PS-Listen to Wolf
Wolf Seril8 years ago
My dad made a fort for me and my brothers when I was very young. We didn't have any trees, So he used 4x4s for as the stilts, and I believe the platform was made of 2x4s. If you don't want the floors to be slats, use at least 3/4 inch plywood. Make sure to put some cross beams for strength, and outriggers for support. If you want several kids or an adult or two to be able to go on it, use 2x6s or even 2x8s. No offense, but by your question I'm guessing you don't know much about construction. Make sure you do your research, and get a friend who knows what he's doing to help you. When it comes to your kids' safety, you can't take any chances.
Just remembered, use bolts for the structural parts, not screws.
ok first pick a tree obvioulsy and build a ladder thats easy to use for little ones i would pick a nailed wood on a tree two or three steps up to a branch you feel youre kids is safe on and on a sturdy branch lay out a big thick wooden pave stone like on the branch and lay it down but nail it down all the way and under it properly hold it up with other bits of wood until YOU can stand on it and then start making the walls by possibly making a pole in the middle to make a roof then gradualy build the walls if you are still concerned please instructable mail me