After pre-construction, foundation work, and utility hookups are complete, a DADU enters one of the most visible and exciting phases of the build: rough construction, often referred to as the shell or dry-in. This is when the structure takes shape, walls go up, and the project begins to feel tangible.
From a cost perspective, this phase represents a major milestone—and a meaningful portion of the overall construction budget.
Construction of the floor system (if applicable), walls, and roof structure that define the shape and layout of the DADU. Simpler designs and lower roof heights fall on the lower end, while taller walls, complex rooflines, and tighter site conditions increase costs.
Typical Cost: $30,000 – $60,000+
Roof underlayment and finished roofing material installed to fully weatherproof the structure. Typical Cost: $6,000 – $15,000, with many straightforward DADU roofs landing toward the lower end of the range.
Installed to secure the building envelope and meet energy requirements. Standard sizes and simple door packages fall on the lower end, while larger openings and higher-performance units increase costs.
Typical Cost: $8,000 – $20,000
Installed to secure the building envelope and meet energy requirements. Standard sizes and simple door packages fall on the lower end, while larger openings and higher-performance units increase costs.
Typical Cost: $8,000 – $20,000
Phase | Expected Range |
Rough Construction | $45K -$95K |
Rough construction is where structural decisions, material choices, and detailing have long-term consequences. Framing accuracy affects everything that follows—from drywall and cabinetry to flooring and trim. Getting the shell right helps control costs later by reducing rework and delays.
This phase also tends to move quickly compared to permitting and foundation work, which can make cost progress feel sudden. Understanding what’s included helps homeowners track the project’s value as it progresses.
