Detached, attached or converted?

A separate building.

A detached proposal creates a physical separation from the main home. Think through the walking route, entrances, shared outdoor space and views between the two households. Where would someone arrive with groceries, meet a visitor or sit outside?

A separate building also needs a complete site and utility conversation. Ask which areas would be affected by construction and how the main home would function while the work is underway.

Space connected to the house.

An attached proposal starts with the meeting point between old and new. Consider household privacy, sound, circulation and the parts of the existing home affected by the connection. Ask your designer to explain the relationship in plan and section.

Do not assume that sharing a wall makes the proposal simpler overall. Structural connections, services, finishes and the intended dwelling use still need assessment for the particular house.

A new use for existing space.

A garage or other existing area may suggest a conversion. Record its current use, structure, access and known services. Ask which elements can remain and which would need alteration for the proposed use. An existing shell is a starting condition, not a cost or approval guarantee.

ADUs and junior ADUs have different requirements. Use the current state handbook and your local authority to establish the category before comparing designs or budgets.

Use one brief for all three options.

Compare the same priorities: who lives there, privacy, access, outdoor use, the effect on the main house, and the complete scope. List unresolved property questions beside each option rather than choosing on a speculative construction number.

• Who will use the space now and later?
• Which routes and outdoor areas would be shared?
• What changes in the main house or garage?
• What needs professional property review?