Top 5 Challenges When Hiring an ADU Contractor — What to Expect and How to Prepare Building an Accessory Dwelling Unit (ADU) is a practical way to add living space and potential rental income. But the outcome depends on one thing above all: choosing the right contractor. hiring the right contractor is essential to avoid delays, unexpected costs, and unnecessary stress. This guide walks you through the five most common challenges homeowners face when hiring an ADU contractor —