This is a treehouse I built with my father over the summer of 2013. The walls are two layers thick and insulated. The porch is cantilevered out about five feet.

We used salvaged materials from a renovation to build the treehouse. The wall studs and windows were salvaged.

The design was almost entirely my own. A structural engineer, a friend of my father's, helped design the support bracing on the bottom. 

Below are some of the plans I drew and some photos I took during construction.

 

Above: plans

Below: photos of construction