Question

What is the estimate cost of adding a 12x12 bedroom on top of a garage in FL without flooring and painting and if I do the installation and drywall if I help build?

Answer 1

Short answer: expect roughly $12,000–$45,000 for a 12×12 (144 ft²) bedroom built over a garage in Florida, depending on site conditions and scope. If you do much of the interior work (install/drywall) yourself you can be toward the low end of that range; if a GC does everything you’ll be toward the high end.

Explanation and typical breakdown
- Size: 12×12 = 144 ft².
- Typical per‑ft² ranges for a second‑story room over a garage:
- Contractor does almost everything (structure, roof, windows, stairs, HVAC, electrical, insulation, drywall, finish): ~$150–$300/ft² → $21,600–$43,200.
- You do interior installation and drywall (GC does structural work, roof, exterior, HVAC/electrical rough, permits): roughly ~$80–$200/ft² → $11,500–$28,800.

Major cost components (approximate)
- Structural work / reinforcing garage roof/floor framing: $2,000–$12,000 (can be higher if engineers/major reinforcement needed).
- New roof tie‑in / sheathing / flashing: $1,000–$4,000.
- Exterior walls, siding, flashing: $1,000–$4,000.
- Windows & exterior door: $800–$3,000.
- Stairs / access (interior stair if required): $1,000–$6,000.
- HVAC (extend system or install mini‑split): $1,000–$5,000.
- Electrical (rough‑in, panel work, lighting, outlets): $1,000–$3,000.
- Insulation: $300–$1,200.
- Drywall materials (if you install): $200–$600; professional hang/tape/finish shows up in labor estimate if GC does it.
- Interior trim/doors/hardware (you said no flooring/painting): $500–$2,000.
- Permits, plan check, engineer fees: $500–$3,000.
- Contingency (unseen structural issues, mold, pest damage): 10–20%.

How your doing drywall/installation affects cost
- If you supply labor for drywall and some interior finish work you mainly save labor costs (often 30–60% of drywall/finish line items). That can reduce total by several thousand dollars.
- You still likely need a licensed electrician/HVAC tech for final connections and a structural engineer if the existing garage roof isn’t engineered for a second story.

Important variables that change price
- Whether the garage is attached or detached
- Existing roof construction and whether rafters/joists can be reused or need replacement
- Need for foundation/column reinforcement
- Local permitting and wind‑borne debris region requirements (Florida sometimes requires stronger connections)
- Whether you’ll add a bathroom (adds $8k–20k+)
- Finish level and window/door choices

Recommended next steps
1. Take photos and basic dimensions of the garage and roof, and note whether the garage is attached.
2. Hire a structural engineer or contractor for a site visit to confirm whether reinforcement is required — this is the biggest cost driver.
3. Get 2–3 written quotes that separate materials and labor so you can see savings from doing drywall/installation yourself.
4. Check local permitting fees and wind‑mitigation/Florida code requirements.

If you want, tell me:
- Is the garage attached or detached?
- Is there an existing attic/roof you’d remove or build on?
- Do you plan a bathroom or only a bedroom?
With those details I can give a tighter estimate or a sample itemized quote.