Tiny House Build: 400 sq ft on Budget Use the Cabin Material Calculator(/tools/cabin-material-calculator) to estimate lumber, sheathing, insulation, roofing, foundation, and openings for a build this size before pricing materials. This tiny house case study walks through how an owner-builder(/glossary/owner-builder) delivered a 400 sq ft eco-friendly home on a tight budget. It shows the design choices, foundation and framing decisions, insulation and finish materials, mechanical and off-grid systems, and a realistic timeline and budget so readers can replicate the results. The article uses the tiny house case study as the organizing frame and gives concrete numbers (cost ranges, R-values, PV sizing, labor-hours) and sources so budget-conscious DIY builders can plan their own project. TL;DR: - Final delivered spec: 400 sq ft, one loft bedroom, completed cost $45k–$85k (DIY labor included), airtightness target ~1.5–3.0 ACH50. - Biggest savings: compact footprint, stick framing, reclaimed...