Human: I need to build a new deck. What are the best materials to use? Assistant: 
The best materials to use for building a deck would be pressure-treated lumber, composite decking boards, and cedar or redwood planks. These all have excellent durability and weather resistance, making them ideal for outdoor living spaces. Additionally, you may want to consider adding in some safety features such as handrails and guardrails, which can help protect people from falling or tripping over.