ADU Site Prep & Utilities in Ojus - Same-Day Service, Done Right the First Time

ADU Site Prep & Utilities in Ojus, FL - Scope, Timeline, and What You’ll Pay

ADU site prep and utilities in Ojus covers everything from clearing your build pad and trenching for sewer, water, and electrical service to pouring footings and roughing in mechanical systems before the structure goes up. Most Ojus projects we handle take 4 to 8 weeks for this phase alone, depending on whether we’re cutting through Miami Limestone or tying into existing mains. Call (844) 665-0162 for a free estimate - we’ll walk your property and give you a written breakdown of exactly what your site needs.

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How We Handle ADU Site Prep & Utilities Step by Step

Every ADU site prep and utilities job in Ojus follows a sequence we’ve refined across dozens of Miami-Dade County builds. Here’s what actually happens, what you’ll need to decide, and how long each stage runs.

Site Survey and Utility Locates (Days 1-5)

We start with a boundary and topographic survey to confirm setbacks, then call in Florida 811 for underground utility locates. In Ojus, this means marking existing water and sewer laterals from Miami-Dade Water and Sewer, plus any private lines from the original 1950s-1970s build. You’ll decide now whether the ADU connects to your main home’s meter or gets independent service - independent adds roughly $3,500-$8,000 but simplifies resale and rental permitting down the road.

Demolition and Clear-Out (Days 6-12)

If we’re replacing an old shed, garage, or clearing mature landscaping, this is when it happens. We haul off debris and test the soil for contamination - older Ojus properties sometimes have buried fuel oil tanks or asbestos siding from mid-century construction. Homeowner decision point: keep any salvageable oak or mango trees, or clear everything for equipment access? We flag protected species per county code before a saw touches trunk.

Excavation and Rock Cutting (Days 13-20)

Here’s where Ojus gets interesting. Miami Limestone sits 1-3 feet below grade across this area, and the water table rides almost as high. Standard backhoes quit; we bring in pneumatic rock hammers or hydro-vac equipment for trenching. Dewatering pumps run continuously during this stage. You’ll choose trench depth and bedding material - crushed limestone base is standard, but we can spec flowable fill if groundwater is aggressive. This stage typically adds 3-5 days versus inland Broward County jobs.

Underground Utilities and Rough-In (Days 21-35)

Sewer lateral, water main tap, electrical conduit, and gas line if you’re heating with propane or natural gas. In Ojus’s HVHZ zone, all underground electrical must be in rigid PVC or Schedule 80 conduit - no direct-burial cable. We coordinate Miami-Dade County inspections for each trade: plumbing rough, electrical trench, gas pressure test. Homeowner call: tankless vs. tank water heater, which determines gas line sizing and electrical panel load calculations.

Footings, Slab, or Piers and Final Grade (Days 36-50)

With utilities in place, we form and pour your foundation. Most Ojus ADUs go on monolithic slabs with post-tension cables or stem-wall construction with fill - your soil report and ADU size drive this. We install vapor barriers and perimeter drainage to combat the moisture intrusion we see constantly in local slab-on-grade homes. Final grading slopes away from the structure per county stormwater requirements. Then we’re ready for the prefab delivery or stick framing crew.

This is part of a full Home Additions & ADU in Ojus project, and our Home Additions & ADU crew coordinates every phase so you’re not managing separate excavators, plumbers, and electricians yourself.

The Material and System Choices You’ll Face

• Foundation type: monolithic slab vs. stem wall. Slabs run faster and cost less upfront - typically $8,500-$14,000 for a 400-square-foot ADU footprint in Ojus. Stem walls with raised floor joists add $4,000-$7,000 but buy you mechanical access underneath and better flood resilience in low-lying pockets near the Intracoastal. If your lot sits below the BFE (Base Flood Elevation), stem walls may be mandatory.
• Water service: tap existing meter vs. independent meter. Tapping your home’s meter saves the Miami-Dade Water and Sewer new connection fee, but caps total flow capacity. Independent service future-proofs for rental use and avoids main-house pressure drops when both units run simultaneously. Budget $2,200-$4,500 for tap and meter vs. $6,000-$12,500 for independent service with trenching.
• Electrical service: overhead drop vs. underground. Overhead is cheaper to install but fails first in hurricanes - and Ojus is HVHZ. Underground costs 40-60% more but satisfies current Miami-Dade wind-load requirements and eliminates the visual clutter of a second service mast. We spec underground for every ADU site prep and utilities job we do in Ojus.
• Sewer lateral material: PVC SDR-35 vs. ductile iron. PVC works for most residential runs and carries a 50-year rating. Ductile iron adds roughly $1,200-$2,800 but resists root intrusion from mature oak canopies common in Ojus’s older neighborhoods and handles ground settlement better if we’re cutting through limestone voids. We recommend iron for runs over 75 feet or where trees overhang the trench line.
• Drainage and moisture protection: basic vapor barrier vs. full sub-slab system. Code minimum is 6-mil poly. We typically upgrade to 10-mil reinforced with a capillary break layer and perimeter French drain - adds $1,800-$3,200 but prevents the musty, efflorescence-prone slabs we repair in neighboring 1960s ranch homes. Given Ojus’s shallow water table, this isn’t where we recommend saving money.

What ADU Site Prep & Utilities Costs in Ojus, FL

Five factors push your number up or down. First, lot flatness and access - a sloped backyard or narrow side yard in eastern Ojus means mini-excavators instead of full-size, adding labor hours. Second, rock encounter depth; we’ve hit solid limestone at 14 inches and at 4 feet, and the difference is a week of hammer time. Third, utility relocation distance - moving your main electrical panel or sewer cleanout to serve the ADU adds $4,000-$12,000 depending on trench length. Fourth, flood zone designation; AE zones require engineered fill and elevated foundations that A zones don’t. Fifth, finish grade and hardscaping - if you want the site restored with pavers or sod versus rough grade, that’s additional.

Our written estimates itemize each of these: earthwork, rock removal, dewatering, utility materials, labor, permits, and inspection fees. What’s not included: Miami-Dade County permit fees themselves (we pass through at cost), landscaping beyond basic sod or seed, and any hazardous material remediation if testing finds buried tanks or asbestos.

Homeowners often pair ADU site prep with other improvements while our crews are mobilized. Many schedule Small & Partial Kitchen Remodels in Ojus or Full Bathroom Remodeling in Ojus to leverage the same project coordination and material procurement.

What Ojus Specifically Does to This Job

Ojus sits unincorporated in Miami-Dade County, which means every permit for ADU site prep and utilities pulls through the county’s Building Department - not a city office like Aventura’s. Contractors who work Aventura or Hallandale Beach regularly often mis-file here, expecting municipal plan review that doesn’t exist. The county-wide inspection queue runs longer than incorporated cities, and the fee schedule is different. We file directly with the Miami-Dade Permitting and Inspection Center and know the specific inspectors assigned to Ojus’s 33160 ZIP.

The HVHZ requirement is the bigger factor. Every structural fastener, window, door, and roofing product must carry a Miami-Dade Notice of Acceptance - stricter than Florida state approval and non-negotiable. We’ve seen out-of-area contractors spec Broward-compliant hardware that fails inspection here, adding weeks and change orders. Our ADU site prep and utilities work in Ojus uses NOA-certified anchor bolts, hold-downs, and connector plates from the start.

The housing stock matters too. Most Ojus homes are 1950s-1970s concrete-block ranches with original single-pane jalousie windows and flat built-up roofs. When you add an ADU, the existing home’s electrical panel and sewer lateral often need upgrading to handle combined load - a hidden cost we flag during our first site walk. And that shallow Miami Limestone with high groundwater? It turns a standard footing excavation into a dewatering operation that inland contractors simply don’t encounter.

Frequently Asked - ADU Site Prep & Utilities in Ojus

Ready to Start Your ADU Site Prep & Utilities in Ojus?

Call (844) 665-0162 to schedule a free on-site estimate. Raymond Estevez or a senior project manager will walk your property, assess rock depth and utility access, and deliver a written, itemized breakdown within 48 hours. No deposit required to get your number.

Written by Raymond Estevez, Owner at Groundwork Construction Co., serving Ojus and South Florida.