Check local building codes, permits, and property boundaries
Choose a healthy, sturdy tree with a strong trunk and large branches
Inspect the tree for disease, rot, cracks, and insect damage
Decide on the treehouse size, height, and design
Gather materials, tools, fasteners, and safety gear
Measure and mark the support points on the tree
Build a safe platform frame using appropriate supports
Attach the frame with tree-friendly hardware
Install floor joists and decking boards
Add wall frames, railing, and roof structure if needed
Build and secure stairs or a ladder
Install walls, roof, windows, and door as desired
Sand rough edges and secure all loose fasteners
Test stability and weight capacity before use
Apply weatherproofing and protective finishes
Inspect regularly for movement, wear, and tree growth adjustments