Two ways to create usable space
A loft or attic conversion adapts existing roof-space conditions. A house extension or home addition creates new finished floor area. Project size and complexity can differ substantially.
Using existing space versus new floor area
An attic or loft project depends on roof space, floor structure, headroom, stairs, and access. An extension or addition depends on the new area, scope, and selected rooms.
Structural complexity, access, and rooms
Staircases, reinforcement, bathrooms, kitchens, and access can be important cost drivers. These projects may require professional structural or building assessment.
United Kingdom and United States terminology
UK profiles use Loft Conversion and House Extension. US profiles use Attic / Loft Conversion and Home Addition. The underlying market methodology also changes with the selected market.
Planning Low, Typical, and High
Planning ranges help compare possible scopes without promising an exact contractor price. Typical is a practical planning reference and may use documented HomeCostNest conventions.
Questions to consider
Consider usable area, access, structural conditions, selected rooms, and the level of finish. Use the calculators to prepare for a professional conversation rather than to replace it.
Plan with the right calculator
Enter your project details and select the United States or United Kingdom market for Low, Typical, and High planning estimates.