Building a stone wall depends on its size, complexity, and construction method (e.g., dry stone walling or mortared). A typical 10-meter-long, 1-meter-high dry stone wall takes 4–5 days for skilled masons. Larger or bespoke projects may require more time. Remember excavations and footings may be required also. For more information you could contact the Drystone Walling Association at https://www.dswa.org.uk/