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Delta Home Additions & ADU: The Miami Owner’s Guide
A full Delta home addition or ADU in Miami typically runs $53,100 – $153,400 for a permitted, turnkey build, depending on square footage, foundation type, and finish level. Mason Remodeling Co Miami handles everything from the first site walk to final inspection, and we stock the framing, rough-in materials, and finish components these projects need, so we’re not waiting on supply houses in the middle of your schedule. Most Miami homeowners start this conversation because an existing addition or ADU has failed in some way: water intrusion at the tie-in wall, a sagging roofline where the old and new framing meet, or an unpermitted conversion that’s now a legal and structural problem. Here’s what to expect, what it costs, and who’s coming to your door.
Which Delta Models This Applies To
Delta doesn’t manufacture additions or ADUs, so the “model” here is really about the structural system you’re adding to or the prefab kit that’s already on site. In Miami, we see three situations most often: a framed addition tied to a 1950s – 80s concrete block home, a manufactured “Delta-style” sunroom or patio enclosure that predates current wind codes, and a garage conversion that was originally built under looser permitting rules. Each has different failure points. The block home tie-in requires control joints and proper flashing where the new wood frame meets the block, and if that flashing is missing or nailed wrong, you’ll see water stains inside within the first two rainy seasons. The older sunroom enclosures often have aluminum extrusions that don’t meet Miami-Dade County’s High-Velocity Hurricane Zone product approvals, so you’re looking at a tear-out and rebuild rather than a repair. The garage conversion issue is usually a slab that wasn’t engineered for habitable load, plus undersized headers over the new windows. Before we quote anything, we verify what’s actually there. An OEM-versus-aftermarket decision doesn’t apply the same way it does for fixtures, but the materials we specify do: pressure-treated sill plates rated for ground contact in our humidity, galvanized or stainless connectors, and either LVL or doubled framing lumber at any point load. We also note one compatibility gotcha Miami owners keep hitting: if your original Delta-era (pre-2001) addition was permitted as a “Florida room,” it cannot legally be reclassified as living square footage without new drawings, and some owners find this out only at resale.
Styles & brands we work with
Signs Your Delta Home Additions & ADU Is Failing
- Water staining at the seam where the addition meets the original house. This is almost always a flashing failure or a control joint that was never installed. In Miami’s daily afternoon storms, even a quarter-inch gap moves a lot of water. Once you see staining, there’s likely hidden rot behind it.
- Cracks wider than 1/8 inch in the floor slab or at corners of windows and doors. In poured-concrete additions, corner cracks often mean the concrete cured without proper saw-cut control joints. In the older conversions, it’s settlement from undersized footers. Either way, water follows the crack and rebar starts rusting from the inside.
- A roofline that dips or sags where the old roof meets the new roof. We see this constantly in Miami additions framed before current uplift codes. The original framing was undersized for wind load, and years of storms have worked the connections loose. A dip you can see from the street is a red flag, not a cosmetic issue.
- Doors and windows that stick only during the wet season. This tells us the framing is moving with moisture. Wood framing swells in Miami humidity, and if the rough openings weren’t flashed or sealed correctly, the fix is more than shaving a door edge.
- Mold smell that comes back after cleaning. Mold in an addition usually means a roof leak, a wall leak, or slab moisture wicking through an unsealed floor. Killing the mold without fixing the moisture source just guarantees it returns.
See the difference
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AfterReplacement Cost & What’s Included
Installed costs for a Delta home addition or ADU in Miami fall into a wide range because the scope varies as much as the lot. The $53,100 – $153,400 range on this page reflects a permitted addition or detached ADU built to current Miami-Dade wind codes: engineered drawings, footers and slab, framing, roofing, rough plumbing and electrical, drywall, finishes, and final inspection. Here’s how the budget lines up:
| Project Type | Typical Miami Installed Range |
|---|---|
| Home Addition (full permitted build) | $53,100 – $153,400 |
| ADU Construction | $106,200 – $259,600 |
| Garage Conversion | $35,400 – $94,400 |
| Roof Replacement (on addition) | $9,440 – $23,600 |
| Impact Window Installation | $9,440 – $29,500 |
What drives the range: whether you’re adding to an existing structure or building a freestanding ADU, whether the lot is accessible for equipment, whether interior finishes are builder-grade or specification-grade, and whether the existing structure needs structural correction before new work can tie in. Every quote we provide in Miami includes a written price before any work starts, line by line, with materials and labor separated. No change orders unless you change the scope. The work is covered by our 365-Day Done Right Promise: if anything we built fails within a year of completion, we make it right at no cost.
DIY or Call Us?
Things you can safely check yourself: visible cracking, water staining, and whether doors have shifted in their frames. Take photos, note when the problems appeared, and whether they get worse after heavy rain. That information helps us quote faster. What you should not do: open up walls or ceilings that may contain wiring, plumbing, or asbestos-era materials, and do not attempt any structural modification – moving a wall, cutting into a slab, or altering roof framing – without an engineer’s assessment. In Miami, unpermitted structural work also creates a resale problem and can invalidate your insurance. If you’re seeing any of the failure signs above, the smart move is a professional inspection. Call (850) 780-8123 and we’ll send someone who’s been doing this work in Miami for over a decade, with a name and photo sent to you before they arrive.
FAQs
How long does a Delta home addition or ADU last in Miami?
A properly permitted, code-compliant addition in Miami should last 50 years or more structurally, but the finishes, roofing, and flashing typically need attention every 15 – 25 years depending on exposure and storm frequency. The biggest factor is whether the original tie-in details were done correctly. Call (850) 780-8123 for an inspection-based assessment rather than guessing.
Can a failing addition be repaired, or does it need to be replaced?
Many Miami additions can be repaired: flashing can be redone, framing can be sistered or reinforced, and cracked slabs can sometimes be stabilized. The decision comes down to what the investigation finds inside the walls and under the roof. Repairs are almost always cheaper than a tear-out, and we’re honest about which one you actually need. Call (850) 780-8123 to schedule a walk-through.
How long does a home addition or ADU build take?
In Miami, a typical framed addition runs 4 – 8 months from permit approval to final inspection; a detached ADU often runs 6 – 12 months depending on site conditions and finishes. The planning and permitting phase typically adds 2 – 4 months before construction starts. We’ll give you a written schedule with the written price, and Isaac Pruett has a reputation for holding to the timeline he quotes. Call (850) 780-8123 for a realistic build timeline for your specific lot.
Do you stock materials for the build, or do we wait for orders?
We keep core framing, flashing, sill materials, and rough-in components on hand, and we order project-specific items like windows, doors, and specification-grade finishes only after your written approval. We work with the same supplier networks across KraftMaid and Cambria as our other trades, so we’re not held up waiting on unknown suppliers. Call (850) 780-8123 and we’ll walk you through the material timeline for your project.
Mason Remodeling Co Miami is an independent service provider and is not affiliated with Delta or any manufacturer mentioned. We work with Delta-era additions, older Florida rooms, and non-conforming conversions every week across Miami, Homestead, and the surrounding communities. If you have a failing addition or want to plan a new one, the first step is a straight conversation with someone who’s done this exact work here for years. Tell me what you need done. I’ll tell you what it costs and when it’s finished – and I’ll mean both.
Call (850) 780-8123 for a written, no-obligation estimate. A live person answers, every time.
Written by Isaac Pruett, Owner, Mason Remodeling Co Miami at Mason Remodeling Co Miami, serving Miami and nearby areas.
