Converting a bi-level (split-level) house into a single-level living space is one of the smartest remodel moves a homeowner can make — especially if you want easier mobility, a modern open plan, and a resale-friendly layout. This guide walks you through why people convert, what to expect in costs and permits, practical construction approaches, flooring and structural tips, U.S.-based vendor suggestions, real-life examples, and a clear checklist you can use to plan your project.
Quick Overview
This post covers:
- What a bi-level/split-level house is and why homeowners convert them.
- High-level costs and market context in the USA.
- Permits, structure, and code basics.
- Practical construction methods (fill, raise, bridge, or add an addition) with product recommendations.
- Design and layout tips.
- Timeline, budget checklist, and contractor selection tips.
Why Convert a Bi-level to Single-Level Living?
Homeowners often convert for these reasons:
- Accessibility: Fewer stairs make life easier for kids, aging relatives, or anyone with mobility challenges.
- Open layout & flow: Single-level plans feel larger and allow modern kitchen/living combinations.
- Resale appeal: Buyers prefer ranch/one-level homes; conversions can improve marketability.
- Energy & HVAC efficiency: Heating and cooling one continuous floor is often simpler than multiple zones.
Tip: Converting a bi-level is a structural change, not cosmetic — expect permits, structural engineers, and solid budgeting.
Common Approaches for Conversion
1) Level Up the Lower Floor (Fill + Raise)
What: Raise or infill the lower-level floor to match the upper level using framed floors, concrete, or lightweight fill with self-leveling underlayment.
Good When: Lower level has enough headroom and foundation allows it.
Pros: Keeps footprint, maintains foundation.
Cons: Structural work, possible underpinning, ceiling height reduction.
Materials/Vendors: Self-leveling underlayments (Rapid Set, LevelQuik, MAPEI) from Home Depot or Lowe’s.
2) Lower the Top Floor (Rare)
What: Remove subfloor and lower framing.
Good When: Ceiling heights and structure allow.
Cons: Often impractical; expensive due to roof, framing, and utility impacts.
3) Build a Short Addition or Ramp (Bridge the Difference)
What: Create a small lateral addition to connect levels on one plane.
Pros: Less intrusive; can add value.
Cons: Exterior work, permits, grading required.
4) Reconfigure Interior (Stair Minimization + Ramps)
What: Reduce stair count with gentle ramps or intermediate landings.
Good When: Full leveling is too costly; improves accessibility incrementally.
Planning, Permits, and Code Basics
- Hire a structural engineer/architect: Confirm load-bearing walls, foundation, and framing can handle changes.
- Check local permits: Structural work, new floors, or plumbing/electrical changes require approval. Experienced remodelers (SeaPointe, NARI members) can pull permits.
- Research zoning and setbacks: Small additions may be blocked by local rules.
- Ask about “Alteration Level 1” under IEBC: Smaller interior adjustments differ from full structural alterations.
Real Costs & Budgeting (USA 2024–2025)
Minor re-level & interior work: $20,000–$60,000
Major conversion with foundation/addition: $60,000–$200,000+
Per sq ft: $200–$500 depending on finishes
Cost drivers:
- Foundation underpinning/new footings
- Plumbing relocations
- Structural reinforcements (LVLs, steel beams)
- High-end finishes
Cost savers:
- Maintain the same footprint
- Reuse mechanical systems
- Choose mid-range materials from Home Depot/Lowe’s
Structural & Materials Checklist
- LVL beams for load-bearing wall replacement
- Steel support beams for long spans
- Self-leveling underlayments (Rapid Set, LevelQuik, MAPEI)
- Subfloor systems and plywood for finishes
- Insulation & vapor barriers
- Floor finishes: engineered hardwood, LVP, tile
Design & Layout Tips
- Prioritize circulation: Kitchen, living, and dining on the main plane.
- Gradual transitions: Use short ramps or gentle steps if floors aren’t flush.
- Daylight & openness: Remove partial walls, add transom windows/skylights.
- Preserve lower-level space: Convert parts to garage, mudroom, or flex space.
Case Study:
The Johnsons in Ohio added a 200 sq ft lateral addition to tie levels together. Used LevelQuik on subfloors and engineered hardwood for a smooth finish. Result: improved flow, aging-in-place mobility, and higher resale value.
Finishing Choices & Trade-offs
- Flooring: Engineered hardwood/LVP forgive minor unevenness; tile requires precise leveling.
- Doorways & thresholds: Low-profile transitions improve mobility.
- Lighting & ceiling: Adjust for floor height changes; consider dropped ceilings if needed.
Hiring Contractors & Comparing Quotes
- Get 3+ detailed quotes including scope, materials, timeline, and permit fees.
- Ask for references with photos and permit numbers.
- Confirm who pulls permits and handles inspections.
- Check NARI membership, HomeAdvisor, or Angi reviews.
- Use contracts tied to milestones (foundation, framing, drywall, finish).
Timeline Expectations
| Stage | Duration |
| Planning & permits | 2–8+ weeks |
| Structural work & framing | 2–6 weeks |
| MEP rough-ins | 2–4 weeks |
| Finishes | 2–6 weeks |
Total: 2–4 months (minor) / 4–8 months (major).
Quick Budget Checklist
- Structural engineer: $800–$3,000
- Architect/design: $2,000–$8,000+
- Permits: $200–$3,000
- Foundation/underpinning: $5,000–$50,000+
- LVL/steel beams: $1,500–$10,000+
- Subfloor leveling: $1,000–$8,000
- Kitchen/bath upgrades: $10k–$60k
- Floor finishes: $2–$15/sq ft
- Contingency: 10–20%
Practical One-Story Conversion Tips
- Start with a structural engineer site visit.
- Keep plumbing close to existing lines.
- Use engineered lumber for long spans.
- Use Rapid Set, LevelQuik, MAPEI for floor leveling.
- Factor in permit/inspection delays.
Local Brands & Places to Shop (USA)
- Home Depot: Self-leveling underlayments, engineered flooring, LVLs, tools
- Lowe’s: MAPEI self-leveler, flooring options, contractor services
- Local contractors: Search HomeAdvisor/Angi for split-level conversion experience
- Specialty suppliers: Regional lumber yards for LVLs, concrete suppliers for lightweight fill
Pitfalls to Avoid
- Skipping structural review
- Under-budgeting for foundation/structural work
- Choosing finishes before confirming floor heights
- Ignoring permits
Step-by-Step Example Plan
- Hire engineer & draw plans (2 weeks)
- Pull permits (2–6 weeks)
- Remove interior partitions & install LVL beams (2–3 weeks)
- Build small addition or frame joists; use self-leveling underlayment (3–6 weeks)
- MEP rough-ins (1–2 weeks)
- Insulation, drywall, paint (2–3 weeks)
- Finish floors, cabinets, trim (2–4 weeks)
- Final inspections & punchlist (1–2 weeks)
Wrapping Up
Converting a bi-level to single-story living improves accessibility, flow, and resale appeal, but it’s a major remodel. Start with a structural engineer, budget carefully, shop trusted brands (Home Depot/Lowe’s), and get multiple contractor bids.
Next Steps:
- Photograph and measure your floor plan
- Book structural engineer visit
- Get 3 contractor quotes including permits
- Request references and permit documentation
- Build 10–20% contingency into budget