Treehouse

Tree houses can be built with a wide range of materials. Wood is commonly used for structural parts and cladding due to its strength, light weight and low cost. Steel is used for brackets, cables and bolts, including specialized tree bolts capable of supporting up to 6,000 pounds (2,700 kg). Builders of tree houses sometimes use recycled materials or parts, such as reclaimed window frames, doors and used lumber. One motivation for this is to promote sustainability by re-using resources. Reclaiming materials can also save money compared with buying new materials and can add a retro or abstract style to the design of the structure. Fabrics can be used to produce non-rigid temporary structures that are more like tree tents than tree houses.
Popularity
Since the mid-1990s, recreational tree houses have enjoyed a rise in popularity in countries such as the United States and parts of Europe. This has been due to increased disposable income, better technology for builders, research into safe building practices and an increased interest in environmental issues, particularly sustainable living.