PopularMechanics.com, TreehouseByDesign.com, OutdoorLife.com and TreehouseGuides.com offer treehouse construction plans. In "How to Build a Treehouse in the Backyard," PopularMechanics.com author Logan Ward describes using a chain hoist to raise the building supplies into the tree. Ward anchored crossbeams to an 8-by-8 green lumber platform with heavy lag screws and installed tongue-in-groove yellow pine floorboards. He left a gap between the platform and the tree to allow it to grow.
TreehouseByDesign.com is a directory for treehouse plans and offers links to other treehouse sites. Some of these plans include a treehouse/swingset combination, a two-level treehouse and an A-frame treehouse. An article on the site instructs visitors on how to build a treehouse using a fire tower as a platform. There is also a discussion about hanging treehouses, which suspend from branches on cables.
OutdoorLife.com provides plans to build an A-frame treehouse, including blueprints and diagrams. TreehouseGuides.com sells blueprints, building instructions and cutting lists for each section. The company provides material lists with each treehouse plan and gears its plans toward beginning builders. Many of its designs are pre-assembled before being raised into the tree. One simple model, the San Pedro, measures 50 square feet and features window seats and a covered balcony. This house takes about two weeks to build.
TreehouseGuides.com also offers plans for multi-tree houses, such as the Alpino model. This house uses a sliding joint to secure the supports to more than one tree without restricting the trees or damaging the structure. Other structures on the site offer options for builders with no trees, including a freestanding treehouse. TreehouseGuides.com advises builders to observe setback rules and utilize healthy trees that can withstand the minor damage caused by anchoring screws.