What is an attached ADU?
It is a complete living unit built onto the side or back of your house. It shares at least one wall with the main home but has its own door, kitchen and bathroom. Many Miami families call it an in-law suite because it is often built for parents or grandparents.
How large can an attached unit be?
Published summaries of Miami 21 put an ADU inside or attached to the house at up to 500 sq ft, as of October 2026. In unincorporated Miami-Dade, the county range for RU-1 lots is 400 to 800 sq ft. Other cities differ. We confirm your limit before sketching.
Does the entrance have to face a certain way?
In the City of Miami, published summaries say an ADU inside the house needs a separate entrance that does not face the street. Even where no rule applies, a side or rear entrance keeps the house looking like a single-family home from the sidewalk, which many neighborhoods expect.
What does hurricane code mean for an addition?
The new walls, roof and openings must meet current High-Velocity Hurricane Zone requirements, even if the original house was built under older rules. The roof tie-in between old and new sections is a common place for leaks and uplift problems, so we detail it carefully in the plans.
Can my parents age in place there?
We can design for it: a no-step or low-step entry where flood elevation allows, wider doors, a roll-in shower and lever handles. If the suite must be raised for flood rules, a ramp or a short lift may be needed, and we show that in the site plan.
Attached suite or detached cottage?
It depends on your lot and your family. An attached suite usually needs less yard and shorter utility runs. A detached unit gives more privacy and is easier to rent to someone outside the family later. We price both if your lot allows both.
Related
As of October 2026. Sources: published summaries of Miami 21 ADU rules; Miami-Dade County ADU and guesthouse page; Florida Building Code High-Velocity Hurricane Zone provisions.
Check what your lot allows
Tell us who the suite is for. We check size limits and the best place to attach it.