Answer
HDB Resale Flat Condition — What to Check Before You Buy
The listing photos look great. The flat looks clean. But what's hiding behind the fresh coat of paint? Here's what to actually inspect.
Answer: The 6 things that cost the most money if you miss them: water leaks ($1,500–$6,000 per bathroom to waterproof), hollow tiles ($3,000–$7,500 to re-tile), spalling concrete (seller must fix — mandatory), pipe corrosion ($3,000–$6,000 to re-pipe), window frame damage ($800–$1,500 per window), and electrical faults ($1,000–$3,000 to rewire). A professional inspection costs $250–$450 and can save you $10K–$20K in surprise renovation costs. For flats older than 15 years, always hire an inspector.
Common Defects & Repair Costs
What to look for and what it costs if you miss it
| Defect | How to Spot | Repair Cost | Seller Must Fix? |
|---|---|---|---|
| Spalling concrete | Crumbling ceiling/walls, exposed rebar | $500–$3,000 | Yes (mandatory) |
| Ceiling leaks | Water stains, bubbling paint | $1,500–$6,000 | Yes (if affects below) |
| Window frames | Rust, gaps, won't lock | $800–$1,500/window | Yes (BCA safety) |
| Hollow tiles | Tap with coin — hollow sound | $15–$25/sqft | No |
| Pipe corrosion | Low pressure, rusty water | $3,000–$6,000 | No |
| Electrical faults | Tripping breakers, dead sockets | $1,000–$3,000 | No |
| Worst case total (old flat, all defects) | $15K–$25K | ||
Mandatory repairs must be completed before HDB approves the resale transaction. Non-mandatory defects are negotiation leverage.
Viewing Checklist by Area
Bathrooms (highest risk area)
- Run shower for 3–5 minutes — check for leaks under vanity and around door frame
- Flush toilet — should refill within 60 seconds, no running sounds after
- Check floor slope — water should flow toward drain, not pool
- Tap all tiles — hollow sounds mean debonded tiles (re-tiling $3K–$7K)
- Look at ceiling for water stains from upstairs bathroom
Kitchen
- Run tap at full pressure — low pressure suggests pipe corrosion
- Check under sink for drip stains or mould
- Test gas point if present (bring lighter)
- Inspect wall tiles behind stove area for grease damage
Windows & Walls
- Open and close every window — should slide smoothly and lock
- Check window sills for water stains (especially windward side)
- Look for cracks wider than 0.3mm — use a credit card as gauge
- Check corridor ceiling outside unit for water stains (your floor's waterproofing)
Planning your HDB resale purchase?
Factor in renovation costs when calculating your true budget. A $500K flat + $65K reno = $565K total outlay.
FAQ
What are the most common defects in HDB resale flats?
The top 5 defects found in resale HDB flats: (1) Ceiling cracks — hairline cracks are cosmetic ($200–$500 to patch), but cracks wider than 0.3mm or with water stains suggest structural or waterproofing issues ($2,000–$8,000 to fix). (2) Hollow tiles — tap every tile with a coin; hollow sounds mean the tile has debonded. Re-tiling costs $15–$25/sqft, and a typical 3-room kitchen + bathroom is 200–300 sqft = $3,000–$7,500. (3) Window leaks — check around window frames for water marks, especially on the windward side. Resealing costs $150–$400 per window; full frame replacement is $800–$1,500 per window. (4) Spalling concrete — exposed rebar on ceiling or walls is a mandatory repair item under HDB rules. Seller must fix before completion. (5) Pipe leaks — run all taps and flush toilets during viewing. Re-piping a 4-room flat costs $3,000–$6,000.
What repairs must the HDB seller fix before selling?
Under HDB's mandatory repairs policy, the seller must fix: (1) spalling concrete — any area where concrete is crumbling and rebar is exposed; (2) ceiling leaks that affect the unit below — the seller must waterproof the affected wet area; (3) damaged or non-original window frames — all windows must comply with BCA safety standards. These are checked during HDB's resale inspection. If the seller doesn't complete mandatory repairs, the resale application cannot proceed. Optional but negotiable: choked pipes, faulty electrical, damaged flooring. You can negotiate a price reduction of $5,000–$15,000 for known defects instead of requiring the seller to fix them — sometimes cheaper and faster to do it yourself with your renovation.
How do I check for water leaks during a viewing?
Three-step water leak check: (1) Visual — look at every ceiling corner and wall-floor junction for water stains, yellowish marks, or paint bubbling. Check behind toilet bowls and under kitchen sinks. (2) Touch test — run your hand along the bottom 30cm of walls in bathrooms and kitchens; dampness means waterproofing has failed. (3) Active test — turn on every tap to full pressure, flush every toilet, and run the shower for 3–5 minutes. Check under sinks for drips. Also check the water meter — if it's spinning with all taps off, there's a concealed leak. Waterproofing a bathroom costs $1,500–$3,000 (hacking tiles + membrane + re-tiling). If both bathrooms need it, budget $3,000–$6,000. This is the single most expensive hidden defect in resale flats.
Should I hire a professional inspector for an HDB resale flat?
Yes, if the flat is older than 15 years. A professional inspection costs $250–$450 for a 4-room flat and typically covers: structural assessment (cracks, spalling), electrical testing (circuit breaker, earthing), plumbing pressure test, window seal check, tile sounding (hollow detection), and a written report with photos. The inspector will catch things you'll miss — like hairline cracks behind furniture, low water pressure indicating pipe corrosion, or electrical circuits that trip under load. For flats older than 25 years, this is essential — hidden defects can easily add $10,000–$20,000 to your renovation budget. The $350 inspection fee could save you $15,000+ in surprise costs.
What is the HDB resale flat viewing checklist?
Bring this to every viewing: (1) Coin or small hammer — tap all floor and wall tiles for hollow sounds. (2) Phone flashlight — check inside cabinets, behind toilet cisterns, under sinks. (3) Spirit level or phone app — check if floors slope toward drains (good) or away (bad). (4) Measuring tape — verify room dimensions match the floor plan. (5) Check all windows open/close smoothly and lock properly. (6) Test every power socket with a phone charger. (7) Flush every toilet, run every tap for 2 minutes. (8) Check the corridor ceiling outside your unit for water stains (indicates your floor's waterproofing). (9) Visit at different times — morning for sunlight, evening for noise. (10) Ask the seller: when was the last renovation, any past leaks, which HDB repairs were done? Take photos of everything — they're your negotiation evidence.
How does flat condition affect the resale price?
Flat condition can swing the price by $20,000–$50,000 on the same floor plan in the same block. A well-maintained 4-room flat (recently renovated, no defects, modern finishes) commands a $20K–$40K premium over an original-condition unit. Conversely, a flat with visible defects (cracked tiles, water stains, outdated wiring) trades at a $15K–$30K discount. The math: if renovation for a pristine flat costs $45K and the original-condition flat costs $65K to bring to the same standard, the $20K price gap makes the original flat the worse deal (you spend $20K more on reno for the same result). Always calculate: purchase price + renovation cost = true cost. A cheaper flat with $30K in hidden repairs is not cheaper.
Related
- HDB Resale Process Timeline — 8–10 weeks OTP to keys
- HDB Resale Negotiation Tips — use defects as leverage
- Renovation Budget Guide — $40K–$65K for 4-room HDB
- HDB Essential Repairs Programme — what HDB covers
- Condo Defect Inspection — new launch DLP checklist
Last updated Feb 2026. Repair cost estimates based on typical HDB renovation quotes in 2025–2026. Mandatory repair requirements per HDB resale guidelines. Actual costs vary by flat age, size, and contractor. This is general information, not professional building inspection advice.