Home Additions & ADU in Miami - One Fixed Price, Permits Handled

Fast, Reliable Home Additions & ADU Across Miami

Home additions and ADU construction in Miami run $53,100-$153,400 for attached room additions and $106,200-$259,600 for detached accessory dwelling units, with garage conversions falling between $35,400 and $94,400. Every project must comply with Miami-Dade County’s High-Velocity Hurricane Zone standards, including current Notice of Acceptance numbers on all impact-rated openings. Call (786) 321-4970 to schedule your free written estimate - we deliver the full price before any work starts.

Call (786) 321-4970

Our crews serve Miami from our South Florida dispatch office, with local permitting experience in Miami-Dade’s product-control system. We know the difference between a window that’s impact-rated and one that carries a current NOA, and we know what that distinction costs if you get it wrong at rough inspection.

Why Rowan Construction Group Miami Is Miami’s Preferred Home Additions & ADU Company

We’ve delivered 4,000-plus projects since 2007, every one with a written flat price before work began and a documented photo record when the crew left. In Miami, that discipline matters more than most places - the HVHZ code layer and FEMA flood-elevation requirements here add permit complexity that out-of-area contractors routinely underestimate.

Our Miami customers leave reviews mentioning the same things: the quote arrived in writing, the change order was signed before the extra work started, and the photo record showed what was behind the wall. The 365-Day Done Right Promise is printed on every contract, backed by The Haven Standard terms page, not an asterisk. Under Clause 1, the price is written before anyone picks up a tool.

Calls are answered by a live person 24/7. Crews are background-checked and uniformed. Grant Rowan built this discipline into the company from the founding year, and it’s what Haven acquired Rowan for - the administrative rigor that keeps projects within a few percent of the agreed number.

Our Home Additions & ADU Services in Miami

ADU Design & Permitting

ADU design and permitting in Miami starts with two questions most generic designers miss: what’s your FEMA flood zone, and what’s the current NOA status on your proposed impact package? Miami’s oolitic limestone bedrock sits feet below grade with a rising water table, so foundation design and flood-elevation compliance here differ from anywhere else in Florida. We handle the Miami-Dade product-control submittal, verify every window and exterior door against the live NOA database, and deliver a permit-ready package with a written price before any dirt moves.

Garage Conversion ADU

Garage conversions in Miami run $35,400-$94,400 and face a specific trap: the existing structure was likely built before Hurricane Andrew or to pre-HVHZ standards, so the roof-to-wall connections, the garage door opening, and the slab elevation may all need upgrade to current code. In neighborhoods like West Flagler and Allapattah, we’ve seen pre-1992 CBS garages without proper hurricane straps that required structural retrofit before the conversion could proceed. We price that work into the original quote, not as a surprise change order.

New Detached ADU

New detached ADUs in Miami are the most complex residential project we handle - $106,200-$259,600, full utility runs, and every exterior component must carry a current NOA. On a detached ADU in Little Havana, our crew pulled the Miami-Dade permit and had to reject a window package the supplier shipped because the NOA on file had lapsed - the units were impact-rated, but without a valid NOA the rough inspection sign-off was never going to happen. We swapped to a current-NOA impact opening package, used hot-dip galvanized anchor bolts on the CBS stem wall instead of the standard fasteners, and worked the open-structure phase ahead of the June-November window so the envelope was closed before storm season. That’s the difference between a quote that includes local knowledge and one that doesn’t.

Junior ADU & Interior Conversion

Junior ADUs and interior conversions in Miami work within existing footprints - often in the pre-Andrew housing stock of Little Havana, Allapattah, and West Flagler - but still trigger HVHZ requirements when any exterior wall is modified or any new impact opening is cut. We evaluate the existing CBS construction, the current roof-to-wall strapping, and the slab elevation against FEMA requirements before quoting, so the price accounts for what we’re actually working with.

Room Additions

Room additions in Miami - $53,100-$153,400 - require matching new HVHZ-compliant construction to existing structure, often pre-1992, often with incompatible fastening and glazing systems. We specify the transition details in the written scope: how the new roof ties to the old, how the impact windows integrate with existing walls, what hardware goes into the new foundation versus what we find in the old one.

ADU Site Prep & Utilities

Site prep and utilities for Miami ADUs must account for porous limestone and high water tables. Standard foundation details from Orlando or Tampa won’t work here - the excavation, the drainage, the sewer lateral depth, and the electrical service routing all require local knowledge. We price this from surveyed conditions, not from a standard template.

Second Story Additions

Second story additions in Miami add lateral load to existing CBS walls that may not have been engineered for it. We evaluate the existing structure, specify the connection hardware, and pull permits with structural calculations included - not as an afterthought.

Sunrooms & Enclosed Patios

Sunrooms and enclosed patios in Miami must meet the same HVHZ standards as the main house if they’re conditioned space or if they alter the existing envelope. We specify impact-rated glazing and proper roof-to-wall connections in the original quote, not as upgrades.

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Trusted Brands We Service in Miami

Our sourcing depth runs across fifty-plus vetted brands, and we specify from that list based on what carries current Miami-Dade NOAs and performs in salt-air conditions. For roofing assemblies on additions and ADUs, we use GAF and Owens Corning systems with HVHZ-approved fastening patterns - not because the brand matters to everyone, but because the documented approval matters to Miami-Dade inspectors and to your insurance underwriter later. We stock local-accessible product lines so replacement windows, roofing shingles, and hardware aren’t delayed by supply-chain gaps when the permit is active and the clock is running.

Common Home Additions & ADU Problems We See in Miami Homes

• Failed rough inspections on impact glazing. Subcontractors from outside Miami-Dade submit impact-rated windows and doors without pulling the current NOA number into the permit submittal. The product is legal in Tampa, Orlando, and every other Florida county, but Miami-Dade inspectors fail the rough inspection anyway. We verify every NOA against the live database before submittal.
• Open structures exposed through hurricane season. Additions and detached ADUs with open-structure phases scheduled into June through November sit exposed through permit backlogs and named storms. We sequence the envelope closure ahead of the window, with contingency built into the schedule.
• Corroded fasteners in coastal CBS assemblies. Standard steel anchor bolts and rebar ties are used instead of stainless or hot-dip galvanized hardware, and Miami’s salt air starts corrosion within a few seasons. We specify corrosion-resistant hardware as baseline on any project near the coast or bay - not as an upgrade.
• Pre-Andrew roof-to-wall connections. Homes in Little Havana, Allapattah, and West Flagler built before 1992 often lack proper hurricane straps. We find this during pre-quote evaluation and specify the retrofit in the original scope, not as a discovered-condition change order.

Pricing for Home Additions & ADU in Miami, FL

We Also Serve Cities Near Miami

Our crews work throughout Miami-Dade and into adjacent municipalities. We regularly permit and build in Miami Beach, where historic-preservation review adds a layer to Art Deco and MiMo structures; Coral Gables, with its strict architectural board; Key Biscayne, where salt-air corrosion resistance is non-negotiable; and Hialeah, with its mix of pre- and post-Andrew housing stock. Each jurisdiction has distinct requirements, and our Home Additions & ADU team knows the difference.

FAQs - Home Additions & ADU in Miami