Eco-Friendly Day Spa Design

I need a comprehensive design and construction plan for a relaxation-focused day spa. The spa will feature sauna and steam rooms, a snow room, and a salt room.

Key Requirements:
- Natural and eco-friendly ambiance
- Incorporation of specified features

Ideal Skills and Experience:
- Experience in spa design and construction
- Strong understanding of eco-friendly materials and practices
- Ability to create a cohesive natural aesthetic

Please provide examples of previous work.