A solid hardwood tree is the foundation of this DIY project. You need to select a strong, healthy tree with deep roots and strong branches, says Michael Feazel, CEO of Roof Maxx. Oak and maple are the ideal treehouse trees, in my opinion.Account for the trees placement in the yard and consider how the treehouse will affect things like light and shadow, the view, and the rain or snowfall in the space. And if you have any doubts about the vitality and viability of the tree you are considering for your treehouse building project, consult with a professional arborist.Should I build a treehouse from scratch or use a treehouse kit?There are essentially two approaches to building your own treehouse: designing it from scratch or using a treehouse kit. Deciding between building from scratch [or] using a kit really depends on the vibe youre after and the level of craftsmanship youre comfortable with, Harvey says. If youre not sure about going full DIY, kits are a good middle ground. They usually come with precut wood, hardware, and instructions, which can save time and headaches. Look for kits that offer flexibility in terms of design so you can add your own personality.If you have some carpentry experience and want to try to DIY your treehouse design, building a treehouse from scratch might be best for you. But if youre looking for some assistance, consider calling in the professionals or purchasing a treehouse building kit to help you along the way.Photo: Sturti/Getty ImagesFor the full experience, building from scratch gives you complete creative control, Harvey says. Its the way I personally love to design, as it allows for custom touches like wraparound balconies, multiple levels, and unique features like a rope bridge or secret passagesor a pulley, zip line, climbing wall, trap door, or whatever else you dream up.Regardless, make a full plan ahead of time, complete with blueprints showing the measurements and materials. The only parts of your treehouse design that should be left more to whim are the finishing elements that are purely ornamental.How to build a treehouseWhat items do I need to build a treehouse?You have to choose durable hardware for your treehouse, and thats true in terms of wood, fasteners, and roofing materials. Use purpose-built hardware, such as lag bolts ora treehouseattachment bolt (TAB), to anchor the structure securely while allowing thetreeto grow and flex naturally, says architect and founder of QY Models Ping Wang. Use sustainably sourced or reclaimed wood for construction, and avoid toxic chemicals in paints, stains, or adhesives.Building with rot-resistant wood is key to a long-lasting treehouse.Photo: Bruce Turner/Getty ImagesAdding to that, Harvey says: For the build itself, use treated wood thats resistant to rot, especially for the platforms and supports. You can also consider cedar or redwood, both of which are quite weather-resistant, but an exterior coating is still a good idea.