Case 1 — Ashiya wooden residence (two storeys + basement)
Site: Ashiya hillside / 220 m² / Category I low-rise residential / north-side setback strict
Structure: timber frame + RC basement / 180 m² GFA
Budget: JPY 120M / Timeline: 10 months
Design decisions
Faced with the north-side setback we chose between sacrificing second-floor volume or excavating. We chose the basement, creating a wine cellar / study. Water table at –3.5 m drove a double-layer waterproofing detail.
Notable details
- South-facing fixed glazing with deep eaves for solar control
- Charred-cedar exterior set against white plaster
- Basement humidity held below 70% with under-floor air supply
Case 2 — Nishinomiya sea-view residence (three-storey RC)
Site: Nishinomiya Shukugawa / 330 m² / Category II mid-rise
Structure: RC wall-frame / 310 m² GFA
Budget: JPY 250M / Timeline: 18 months
Design decisions
The southwest sea view became the brief. We placed the living floor on level three — kitchen, lounge, guest suite, jacuzzi terrace. Ground floor held three cars and services.
Notable details
- 8 m column-free opening on level 3, achieved with prestressed beams
- Jet-finished granite envelope
- Inverted-beam roof for clean, leak-resistant waterproofing
Case 3 — Hokusetsu two-generation residence (hybrid two-storey)
Site: Toyonaka Shinsenri / 280 m²
Structure: RC ground + timber upper / 240 m² GFA
Budget: JPY 90M / Timeline: 12 months
Design decisions
Parents on level 1, children on level 2. RC at ground for acoustic separation and fire safety, timber above to keep the structure light — also seismically favourable. A courtyard divides the circulation while preserving sightlines.
Notable details
- Shared 7 m² genkan wide enough for prams and wheelchairs
- Hand-trowelled mineral plaster paired with seam-folded galvalume cladding
- Independent hot-water and electricity meters per generation
Copying a case doesn't help. Copying the decision logic does. Site, family, budget, and climate combine differently each time.