When an attic conversion makes sense
You have an unfinished attic with at least 7 feet of clear height at the peak, accessible stairs (or room to add them), and a roof that is in good condition. The home has a single story or a story-and-a-half layout where the attic is currently dead space. The conversion typically adds 400-1,200 sq ft of living space — usually a bedroom, bath, and possibly a small living area or office.
Cost in Louisville 2026
Basic attic conversion (bedroom + small sitting area, no bath, dormers if needed): $40K-$70K. Mid-range attic conversion (bedroom + full bath + dormers): $70K-$120K. Premium attic conversion (primary suite with walk-in closet, full bath, custom built-ins, dormers, sky lights): $120K-$200K. These are turnkey including electrical, HVAC, and finish.
The 3 things that surprise homeowners
1. The stair. Building a code-compliant stair to a new attic space often costs $8K-$15K. You need a minimum 36-inch width, proper rise/run, handrails, and headroom at top and bottom. 2. The HVAC extension. Your existing HVAC may not have the capacity. Ductwork extension to the attic costs $3K-$8K. 3. The roof penetrations. Every skylight, dormer, and roof vent is a potential leak point. We use high-quality flashing and ice-and-water shield under all penetrations.
Do you need a permit
Yes. Louisville Metro requires a building permit for any attic conversion that adds living space. You also need: (1) construction drawings, (2) structural drawings sealed by an engineer (the floor joists and rafters need to support the new loads), (3) electrical permit, (4) plumbing permit if you are adding a bath, (5) HVAC permit.
What about the roof
If your roof is over 15 years old, replace it AT THE SAME TIME as the attic conversion. The cost difference between doing it during the conversion and doing it 2 years later is minimal. The disruption difference is huge. We will tell you upfront if your roof needs replacement.
How long does it take
A basic attic conversion: 4-6 weeks. A mid-range with bath: 6-10 weeks. A premium with dormers and primary suite: 10-16 weeks. The schedule depends on permit timing, structural surprises, and material lead times.
Common mistakes
1. Skipping the structural engineer. "We have attic trusses, we are fine" — sometimes yes, sometimes no. 2. Not planning for the stair. A pull-down ladder is not a permanent access solution. 3. Underinsulating. Attics need R-38 to R-60 in Louisville. Spray foam is the best option for sloped attic ceilings.
How we approach attic conversions
We do a structural assessment first. We tell you upfront if the attic can be converted and what it will cost. We do a feasibility study with floor plans and a fixed price before we sign a contract. We sequence the work: structural reinforcement, HVAC extension, electrical, plumbing, drywall, flooring, finish.