Your Contractor Won't Tell You These 7 HDB Hacking Rules (Number 4 Cost Me $3,000)

"Can hack, no problem!" my contractor assured me, already reaching for his drill. Thank God I stopped him. That wall he wanted to demolish? It would've cost me my entire renovation deposit plus a $5,000 fine.

After that near-disaster, I spent two weeks studying actual HDB regulations. What I found contradicts 90% of what contractors tell you. Here are the seven rules that will save your wallet and your sanity.

The Real Story

My Serangoon 4-room flat had this awkward wall between the kitchen and living room. Every contractor who visited said the same thing: "Hack lah! Open concept, very nice, everyone doing."

But something felt off. The wall looked... different. Thicker. The sound when knocked wasn't quite hollow. I decided to check with HDB directly before proceeding.

The HDB officer pulled up my flat's original blueprint. His face changed. "This is a structural wall, sir. If you hack this, the ceiling might crack. Maybe not today, maybe not tomorrow, but eventually."

That "can hack" wall? It was holding up part of my neighbor's flat above. My contractor had renovated 20 units in my block. How many structural walls had he demolished? The thought still haunts me.

I started documenting every single HDB hacking rule, cross-referencing with actual permits, talking to HDB engineers. The rules are clear. The problem? Nobody reads them, and contractors assume they know better after "30 years experience, bro."

What Most People Don't Know

Here are the seven hacking rules that contractors routinely violate or misunderstand:

Rule #1: The 3pm Rule You can only hack until 3pm on weekdays. Not 3:30pm, not "almost finish already," exactly 3pm. My neighbor got warning letter for 3:15pm hacking. Second offense? $500 fine. Third? $1,000. The Town Council has sound meters now. They know.

Rule #2: The Half-Wall Trap Contractors love suggesting "hack half only, keep structure." HDB's actual rule: any wall modification needs permit if it's connected to structural elements. That half-wall hack? Still needs approval. Without permit: $5,000 fine minimum.

Rule #3: The Bomb Shelter Boundary Cannot hack ANY wall connected to your bomb shelter, even if it looks like normal partition. These walls are calculated into the shelter's structural integrity. One Punggol owner hacked a "partition" next to his bomb shelter. Result: $8,000 fine plus forced reconstruction.

Rule #4: The Floor Hack Scam (This one cost me $3,000) Contractor said: "Must hack original floor tiles, if not new tiles will pop." HDB reality: Overlay is perfectly fine if done correctly. I paid $3,000 for unnecessary hacking, two weeks of dust, and disposal fees. Later found out same contractor overlaid another unit without issues.

Rule #5: The Window Wall Modification Any wall with a window is considered "facade wall." Even internal modifications need BCA approval, not just HDB. My friend changed his kitchen window wall layout. Looked great until HDB inspection. Forced to restore: $6,000.

Rule #6: The 125mm Rule Partition walls cannot exceed 125mm thickness when rebuilt. Contractors often build thicker walls for "better sound proofing." HDB inspection will fail you. Must tear down and rebuild. Seen it happen three times in my block alone.

Rule #7: The Wet Area Restriction Original wet areas (bathrooms/kitchens) walls contain waterproofing membranes. Hack these without proper restoration, water seeps to neighbors. You're liable for ALL damage. One Bedok owner paid $12,000 for neighbor's ceiling/wall repairs after improper kitchen wall hacking.

The Clementi Test Case

Block 312 Clementi became famous in contractor circles as "The Hacking Massacre." In 2023, HDB did surprise inspections after multiple complaints. Results:

• 18 out of 24 renovating units had illegal hacks
• Total fines issued: $87,000
• 5 units forced to rebuild walls
• 3 contractors lost their HDB license

The worst case? Unit #10-456 had hacked their entire flat into open concept, removing six walls. Only the bomb shelter remained. Their fine: $15,000. Restoration cost: $20,000. The contractor? Disappeared.

But here's the twist: Unit #08-456 (same layout) also went open concept but passed inspection. Why? They got proper permits, hired structural engineer for assessment, reinforced support beams. Extra cost: $4,000. Potential savings from avoided fines: $15,000.

The lesson? It's not that you cannot hack. It's that you must hack legally. The difference between legal and illegal is often just paperwork and proper methodology.

Your Action Plan

• First call: Request your flat's original blueprint from HDB (MyRequest@HDB app). It's free and shows which walls are structural.
• This weekend: Take photos of every wall you plan to modify. Submit to HDB via email for preliminary approval before contractor starts.
• Before contractors arrive: Print HDB renovation guidelines. When contractor says "can," show guidelines, ask "where does it say can?"
• Red flag to watch: Contractor who says "don't need permit one." EVERY hack needs documentation, even if approval not required.
• Budget hack: Skip floor hacking unless tiles are actually damaged. Overlay saves $3,000 and two weeks of dust. Use that money for better materials instead.

The Bottom Line

Your contractor's "can hack" means "I've done it before without getting caught." But you're the one paying fines, not him. Every hack needs verification, most need permits, and some are absolutely forbidden regardless of what your contractor's "experience" tells him. Check first, hack later, sleep peacefully.

Conversation Starters

Which "confirmed can hack" advice turned out to be illegal for you?

Has anyone successfully appealed an HDB hacking fine?

Contractors reading this—what's your side of the story?