🔍 A 5-room HDB interior design and renovation in Singapore costs about $55,000–$90,000 for a BTO flat and $70,000–$120,000 for a resale flat in 2026. With roughly 110 sqm or more, the best 5-room designs use an open living-dining-kitchen core, turn the third bedroom into a flexible study, and plan storage zones by family member. The extra space suits Italian Minimalist, Modern French and Modern Luxury styles. 5-Room HDB Interior Design Singapore 2026: Ideas, Layouts & Reno