Pool projects take varying amounts of time to complete, depending on their complexity and scale. A project can also be delayed by bad weather. The project manager will follow an established timeline, but most projects take between three and four weeks to complete. The landscaping and construction of a substantial backyard project can take two to three months. This accounts for permits, design work, excavation, plumbing and electrical work, construction, the final deck architecture, and details pertaining to landscaping.