Buying a Resale Flat: Renovation & Rewiring Checklist

When you buy a resale flat in Singapore, walk through it with a clear checklist before you commit to any works: inspect the electrical wiring and consumer unit, test every socket and light point, check wet areas for waterproofing and leaks, and confirm which changes need HDB permits or MCST approval. For most older resale flats the priority items are rewiring or upgrading the electrical system, redoing bathroom and kitchen waterproofing, and hacking or replastering tired surfaces.

A resale flat is not a blank canvas the way a BTO is. The previous owner's wiring, plumbing and finishes may be decades old and not built for how you live today. Older flats often ran on lower electrical loads, fewer power points and single-phase supply that struggles with modern air-conditioning, induction hobs and instant heaters. Going through the flat systematically before renovation lets you plan a realistic scope and budget instead of discovering nasty surprises after you have moved in.

What should you inspect before renovating a resale flat?

Do a proper walk-through before you sign a renovation contract. Bring a phone charger to test sockets, run taps, flush toilets and switch on every light so you know what actually works.

Focus your inspection on the systems that are expensive or disruptive to fix later rather than cosmetic finishes you were going to change anyway.

• Electrical: age of the consumer unit (fuse box or DB box), whether there is an ELCB or RCCB safety trip, number of power points and any scorch marks or warm sockets.
• Wet areas: signs of water stains, musty smell, hollow or lifted floor tiles, and how old the bathroom and kitchen waterproofing looks.
• Plumbing: water pressure at taps, slow drainage, rusty water on first flow and the condition of concealed or exposed pipes.
• Structure and finishes: cracked tiles, uneven floors, ceiling stains from the unit above and window or door frames that stick.
• Aircon: age and servicing history of existing units, and whether ducting or trunking is reusable.

Does a resale flat need rewiring?

Not every resale flat needs a full rewire, but many older ones benefit from at least a partial upgrade. As a rough guide, if the flat is more than 20 to 25 years old and the wiring, consumer unit or power points have never been touched, budget for rewiring or a substantial electrical upgrade. Old rubber or PVC insulation becomes brittle over time, and older boards may lack modern earth leakage protection.

Signs that point toward rewiring include an old-style fuse box without a proper safety trip, frequent tripping, flickering lights, discoloured or warm sockets, and too few power points for your appliances. In Singapore, work that touches the incoming supply or the electrical installation should be done by a Licensed Electrical Worker (LEW), and adding significant load may require the LEW to apply to SP Group. Never let a general handyman rewire a distribution board.

What are the must-do electrical upgrades?

Even if you keep most of the existing wiring, a few electrical upgrades are worth doing while walls are open and before you lay new flooring. Getting these right early avoids hacking finished surfaces later.

Prioritise safety first, then convenience.

• Install or confirm an RCCB or ELCB in the consumer unit so the supply cuts out on earth leakage.
• Add dedicated circuits for heavy loads: air-conditioning, water heater, oven or induction hob, and kitchen appliances.
• Increase the number and placement of power points, including near the TV console, study desk, bedside and kitchen counter.
• Provide proper points for instant water heaters in bathrooms and a suitably rated point for a storage heater if used.
• Plan data, network and enough USB or charging points so you are not relying on trailing extension cords.

What about waterproofing and plumbing in the wet areas?

Bathrooms and the kitchen are where hidden problems cost the most. If you plan to overlay or hack existing bathroom tiles, treat waterproofing as non-negotiable: the membrane should be redone and water-tested before new tiles go down, otherwise leaks can seep into your unit or the neighbour below.

Check that floor traps drain quickly, that there is no long-standing dampness, and that any concealed piping is sound. For HDB flats, note that hacking the bathroom floor and doing a full overhaul is usually only permitted within the first three years for the original screed, so factor timing into your plan. If in doubt, a good contractor should advise whether an overlay or a full hack-and-redo makes more sense for your flat's age and condition.

Which resale renovations need HDB or MCST approval?

Cosmetic works like painting, new flooring over existing screed and built-in carpentry generally do not need a permit, but structural and wet-area works often do. For HDB flats, hacking walls, changing the toilet or floor finishes, and certain plumbing or electrical changes require an HDB renovation permit, and the work must be carried out by an HDB registered renovation contractor.

Never touch structural walls, columns or the reinforced concrete: removing or hacking them is prohibited and dangerous. For condos and private apartments, check with your MCST or managing agent, since they set rules on renovation hours, floor loading, water shutdowns and often require a deposit. Confirm approvals before any hacking starts so you are not forced to reverse completed work.

• HDB permit needed: hacking walls, floor and wall finishes in wet areas, and specified plumbing or electrical works.
• Always prohibited: hacking structural walls, beams, columns or the flat's reinforced concrete slab.
• Condo and private: MCST approval, renovation timing, noise rules, lift protection and a refundable deposit.

How much should you budget, and how do you get it done right?

Resale renovation costs vary widely with the flat's condition, size and how much you hack and rebuild. As a general Singapore range, a light refresh of a resale flat can start in the low tens of thousands, while a full overhaul with extensive hacking, rewiring, new wet areas and custom carpentry can run well past that, sometimes into the higher tens of thousands for larger flats. Treat any figure as a starting point and get an itemised quote based on your actual scope.

The cleanest way to avoid coordination headaches is to have one team handle the renovation, electrical and plumbing together so the trades are sequenced correctly. Because we cover renovation, electrical and plumbing under one roof, a resale flat renovation package lets us inspect the flat, plan the rewiring and wet-area works, handle HDB registered works and give you a single itemised quote instead of chasing separate contractors who blame each other when something goes wrong.

Frequently asked questions

Do I need to rewire every resale flat? No. Newer flats or ones that have already been upgraded may only need minor electrical additions. Older flats with original fuse boxes, few power points or signs of wear usually need at least a partial rewire, which a Licensed Electrical Worker should assess.

Can I renovate before I collect the keys? No. Renovation and inspection access only start once the resale transaction completes and you have the keys, though you can plan the scope and gather quotes earlier so work can begin promptly.

How long does a resale flat renovation take? A light refresh may take a few weeks, while a full hack-and-rebuild with new wet areas, rewiring and carpentry commonly runs around eight to twelve weeks or more, depending on scope and approvals.

Who is responsible for HDB permits, my contractor or me? The renovation must be done by an HDB registered contractor, and in practice a reputable contractor applies for the required renovation permit on your behalf. Confirm this in writing before works begin.