February 25, 2026 - Teardown and Build New, or Remodel in Keystone Islands?
Should you breathe new life into that mid‑century canal home or clear the slate and build your dream estate from the pilings up?
In this guide, you will learn a framework to compare a remodel to a teardown, the permitting path for seawalls and docks, realistic cost ranges, and the due‑diligence steps that protect your budget and timeline.
How property value works in Keystone Islands
Waterfront property value in Keystone Islands and other coastal neighborhoods are highly sensitive to a number of criteria including linear water frontage, lot size, property age, and exposure to open water versus interior canals. Buyers pay more for larger lots, new(er) homes, updated dock infrastructure, deeper water, open water views, privacy, and quick access to Biscayne Bay with no fixed bridges. Interior finishes, style and design do matter, but on resale, your water frontage, property age, lot size and position, dock infrastructure and boating capability carry more weight.
Frontage and exposure
More linear feet on the water generally means a larger lot and higher price ceiling on resale. Lots with wider canals or open‑bay views have stronger sight lines and less visual obstruction. Corner and outer‑canal parcels trade at a premium because they often deliver faster access to the bay and more privacy.
Dock depth, vessel size and navigable
Serious boaters care about draft, tidal range, excessive wake and turning space. If your canal depth supports larger yachts and your permit envelope allows a lift or slips without over‑projecting into the waterway, you expand your buyer pool. Before you model resale value, confirm true depth and feasible dock dimensions with a local marine engineer.
Turnkey premium
Turnkey and new(er) contemporary waterfront homes with modern systems, newer dock infrastructure, and deep‑water dockage are marketed at the top of the Keystone range. Renovated older homes trade at significantly lower per‑foot prices than new, elevated builds on the same lot. If you can pair a superior lot with a modern build and strong dock specs, you typically maximize the exit price.
Remodel vs teardown framework
Use this three‑part test to compare scenarios on your specific lot.
Test the 50 percent rule
Under FEMA’s Substantial Improvement rule, if your renovation cost equals or exceeds 50 percent of your building's current market value, the entire structure must meet today’s flood and building codes. That can mean elevating the home to Base Flood Elevation, adding flood openings, changing foundations, and upgrading materials. Always confirm with an Elevation Certificate and a pre‑permit review so you know if your scope will trigger the rule.
See FEMA’s guidance on when a home must be elevated for details: FEMA’s 50 percent rule overview. Also, see the Forerunner geospatial tool to determine the specific property's flood zone and base flood elevation. Currently, the majority of Keystone and Sans Souci homes are located in flood zones AE or VE, which require a base food elevation from 8 to 11 feet.
Costs to compare
Create side‑by‑side budgets that include hard and soft costs for both paths.
- Demolition: often $6 to $15 per square foot in Florida, plus permits and disposal. See a Florida overview of demo costs in this guide to house demolition pricing.
- New luxury waterfront construction: commonly $400 to $1,000 plus dollars per square foot, depending on elevation, complexity, and finishes. For context, review this luxury home cost guide.
- Seawall work: typical replacement ranges $1,000 to $1,500 per linear foot, with premium systems higher.
Include design, surveys, engineering, permits, and a robust contingency. If seawall or dock work is needed, budget these as separate line items.
Timeline expectations
Expect a city building review plus county and possibly state or federal approvals for water‑adjacent work. Miami‑Dade’s Department of Environmental Resources Management reviews most seawall, dock, and dredge permits, and the county adopted a 2025 ordinance to streamline and track processing with a new Gold Key workflow. A conservative entitlement window is still 6 to 18 months for typical projects that do not require extensive state or federal reviews. See the county’s permit process update in the 2025 seawall ordinance summary.
Seawalls and docks matter
Common seawall issues include failing caps, tieback loss, and scour under the toe. A marine engineer inspection with diver assessment is essential. Replacement costs vary widely with access and exposure, and some sites may qualify for living seawall solutions. The county’s 2025 update includes measures to improve permitting clarity for these projects.
Dock limits and dredging
Miami‑Dade sets dimensional limits on private docks, including general guidance that docks should not protrude more than 25 percent of a waterway’s width without higher review. Enlargements, new slips, or dredging can trigger Class II or III permits and, in some cases, state and federal approvals. See county guidance summarized in this dock and dredge policy reference.
If work moves waterward of the mean high water line or modifies the bulkhead line, Florida sovereignty submerged lands rules can apply, and you may need a joint coastal permit or other authorization. In navigable waters, the U.S. Army Corps may also review.
Lot and soils realities
Coastal lots in North Miami typically sit over oolitic limestone with near sea‑level groundwater. Elevated, pile‑supported foundations are common for new builds that must meet current flood standards.
Step‑by‑step due diligence
Use this suggested sequence to limit your risk and protect your timeline.
(1) Zoning confirmation
Request a zoning verification and pre‑application meeting with the City of North Miami to confirm setbacks, height, and coverage per the Land Development Regulations.
(2) Flood and elevation data
Order any existing Elevation Certificate or commission a new one. Review current flood zone data using FEMA’s Map Service Center tools.
(3) Seawall and dock inspection
Engage a marine or structural engineer for a seawall inspection that includes underwater review. Seek two contractor opinions with repair versus replacement pricing.
(4) Survey and records
Order a boundary and topo survey. Identify canal easements, bulkhead lines, and rights‑of‑way. Check recorded permits and folio data through the county’s building and permitting portal and the Miami Dade Property Appraiser.
(5) DERM pre‑screen
Ask Miami‑Dade DERM to pre‑screen your seawall and dock scope. Confirm whether state or federal approvals are likely and inquire about the county’s Gold Key tracking. Reference the 2025 seawall permit process update.
(6) Side‑by‑side budgets and comps
Obtain three estimates from a qualified GC: A) remodel, B) partial teardown while retaining seawall, and C) full teardown and elevated new build. Include soft costs, contingencies, and seawall or dock work as separate lines. Pair your budgets with island‑specific comparable sales modeled by a waterfront real estate specialist to determine exit prices.
When teardown often wins
Teardown plus new construction usually pencils better when:
Your remodel budget will likely exceed the 50 percent threshold, which would force full code upgrades anyway. See how the rule applies in FEMA’s overview.
- The seawall needs full replacement, and the combined wall plus remodel cost approaches a large share of total project value.
- The market expects an elevated, modern floor plan, and your existing structure cannot deliver that layout efficiently.
- Your lot has strong waterfront metrics, such as wide frontage, deep water, and quick bay access, which support a premium exit price.
When a remodel can still work
A carefully scoped remodel can be a good option if:
- Your renovation stays safely below the 50 percent threshold after an official valuation.
- The seawall is structurally sound or needs only modest repair, and your dock already fits your boating needs.
- Your timeline favors speed and you can deliver move‑in ready condition without major foundation or elevation changes.
- The lot is on an interior canal with a more modest price ceiling, where a cost‑controlled refresh can meet the market efficiently.
Resale and insurance effects
Under FEMA’s Risk Rating 2.0, flood insurance pricing reflects first floor height, distance to water, and replacement cost, among other factors. Elevating a new build and improving flood resilience may lower premiums for future buyers, which can support marketability. Review how Risk Rating 2.0 works here: FEMA’s Risk Rating 2.0 overview.
Work with a hyper-local waterfront specialist
Your decision should come from facts on your specific lot, not rules of thumb. A clear path includes verified flood and elevation data, a real seawall inspection, a candid look at dock potential, and a builder’s budget for each scenario. If you want a captain’s‑eye view of dockage, seawalls, and navigation paired with luxury marketing and precise comps, connect with Captain Ross to book a Dock‑to‑Doorstep consultation.