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Cover Home Additions & ADU: The Miami Owner’s Guide
If you’re planning a home addition or ADU in Miami and you’ve been working with Cover, you already know the platform gives you a clean design, a set of specs, and a permitted plan set. What it doesn’t give you is a crew that shows up verified, a written price before work starts, and a one-year guarantee on the build. That’s where we come in. A Cover home addition in Miami typically runs $53,100 – $153,400 fully permitted and built, while ADU construction ranges from $106,200 – $259,600 depending on size, site conditions, and finish level.
Most owners reach out to us after hitting a wall with the Cover process. The plan exists. The financing might even be approved. But the project stalls because finding a contractor who will actually honor the Cover spec sheet, pull Miami-Dade permits correctly, and show up with a crew you can verify by name and photo turns out to be the hard part. We’ve built enough Cover-spec projects across Miami to know exactly where the gaps are, and we close them.
Mason Remodeling Co Miami is an independent contractor. We’re not affiliated with Cover, and we don’t sell Cover-branded products. What we do is take Cover’s design intent and build it to Miami-Dade code, with real numbers and real accountability.
Which Cover Models This Applies To
Cover’s home addition and ADU plans span a few common configurations, and the cost to build them in Miami depends heavily on which one you have. The single-story rear addition is the most common, running roughly 400 – 700 square feet. The detached ADU is next, usually 500 – 1,000 square feet with its own electrical panel and meter. Garage conversions are a third path, especially in older Miami neighborhoods where the garage is already detached and underused.
The compatibility issue most owners miss: Cover’s plans assume California structural minimums unless you specifically requested Miami-Dade wind load. That’s the single biggest change order we catch. Miami-Dade requires impact-rated windows, stronger roof tie-downs, and different foundation details than a California plan will show. If your Cover plan set hasn’t been engineered for Miami-Dade County, it needs a Florida-licensed engineer to revise it before we can pull permits. That revision typically adds $2,500 – $6,000 to the job, so ask Cover about it before you buy the plan.
Spec-wise, Cover additions typically call for 2×6 exterior walls, which is fine for Miami. The roof slope is usually low, which is why we specify peel-and-stick underlayment and a high-temperature cap sheet rather than standard felt. Humidity inside a Miami ADU is a real thing; the bathroom exhaust fan in a stock Cover plan is often undersized for our climate. We swap in a 110 CFM unit as standard.
Styles & brands we work with
Signs Your Cover Home Additions & ADU Is Failing
- Permits rejected on first submittal. This is the most common failure point. Miami-Dade plan review rejects Cover’s stock drawings for wind load, flood zone, or egress. Each rejection cycle costs you three to five weeks.
- Contractor won’t honor the Cover spec. You get a quote that’s $40,000 over, or the contractor ghosts you after seeing the plan set. The plan isn’t the problem; it’s that the spec requires more precision than a typical crew wants to deliver.
- Foundation cracks within the first year. South Florida soil settles unevenly. If the slab wasn’t poured with proper compaction and rebar spacing, hairline cracks show up fast, especially near the tie-in between the new slab and the existing house.
- Moisture and mold at the roofline. Miami’s humidity finds every gap. If the roof-to-wall flashing was rushed or the vapor barrier wasn’t taped correctly, you’ll see staining at ceiling corners within six months.
- HVAC that can’t keep up. A 500-square-foot ADU in Miami needs a real load calculation, not a rule of thumb. Undersized units run constantly, spike your bill, and still leave the space humid.
See the difference
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AfterReplacement Cost & What’s Included
For the build itself, here’s what we quote in Miami right now:
- Home addition (400 – 700 sq ft): $53,100 – $153,400
- ADU construction (500 – 1,000 sq ft detached): $106,200 – $259,600
- Garage conversion (400 – 600 sq ft): $35,400 – $94,400
The spread comes down to three things: finish level, site conditions, and whether the Cover plan needs Miami-Dade engineering revisions. A basic addition with builder-grade finishes sits at the low end. A detached ADU with its own kitchen, impact windows throughout, and a separate electrical service sits at the high end. Tree removal, underpinning, and flood zone elevation requirements all push the number up.
Every quote we give includes permits, engineering revisions, materials, labor, and a written line-item breakdown. No allowances that balloon later. The price we write down is the price you pay, unless you change the scope. And the whole build carries our 365-Day Done Right Promise: if something isn’t right within a year, we make it right at no cost.
DIY or Call Us?
If you’re still in the planning phase, there’s real value in doing your own homework: confirm your property’s flood zone on the Miami-Dade GIS map, check your setback requirements, and ask Cover directly whether the plan set includes Miami-Dade wind load. That research is safe, free, and will save you a cycle of permit rejection.
What you shouldn’t do is act as your own general contractor on a full addition or ADU. This isn’t a vanity swap. You’re tying a new foundation into an existing structure, running new electrical service, and waterproofing a roofline against Miami’s hurricane season. Code violations here don’t just fail inspection; they fail insurance claims after a storm. If you want the work done right, with a written price and a real guarantee, call us at (850) 780-8123. Tell me what you need done. I’ll tell you what it costs and when it’s finished, and I’ll mean both.
FAQs
A properly built Miami-Dade addition or ADU should last 50+ years on the structural shell, with the roof needing replacement every 15 – 20 years and the HVAC lasting 10 – 12 years in our climate. The key is the initial build quality: tie-downs, flashing, and slab compaction determine whether you get a 50-year structure or a 15-year headache. Call (850) 780-8123 if you want a build that lasts.
In our experience, roughly 80% of Cover plans need at least one Miami-Dade engineering revision before permits clear, usually for wind load, flood zone, or egress. You should budget $2,500 – $6,000 for that revision. We include it in our quote; call us and we’ll line-item it so there’s no surprise.
A home addition typically takes 4 – 8 months from permit approval to final inspection. A detached ADU runs 6 – 12 months. Garage conversions are faster at 3 – 5 months. The permitting phase in Miami adds 4 – 12 weeks on top of that, depending on your municipality. We give you a schedule up front and we hold to it.
We stock the common infrastructure: Miami-Dade rated fasteners, hurricane ties, standard-size impact windows, and roof underlayment. For finish materials like cabinetry, we order through our trade partnerships with KraftMaid, Cambria, and Silestone, which gives you spec-grade options without retail markup. The order is placed once the slab is poured, so there’s no material sitting in a Miami warehouse warping in the humidity.
Written by Isaac Pruett, Owner, Mason Remodeling Co Miami at Mason Remodeling Co Miami, serving Miami and nearby areas.
