Contingency and sequencing for a 55 m² Jakarta flat renovation

rue_numbers

Property investor
Established
IDR 3,003,000,000 is the initial renovation figure for a 55 m² new-build flat, and I do not yet know how much of it is firm scope rather than allowances. The plan includes work to the kitchen and bathrooms, floor and wall finishes, electrical testing and limited efficiency improvements, without adding to the structure.

I can phase decorative choices, but faults involving electricity or water would need immediate attention. What reserve makes sense while plumbing routes, moisture risks and trade sequencing remain unclear? I would also like contractors to identify exclusions, assumed approvals and any access or procurement issue that could delay the essential work.
 
I would provisionally hold 10% if the layout and service routes are staying unchanged, rising toward 15% until the electrical scope, plumbing access and moisture condition are understood. The percentage matters less than keeping that reserve outside the contractor’s base price so it cannot quietly become spending money.
 
Before settling on that range, is the IDR 3,003,000,000 construction-only? Appliances, loose furniture, design fees, building charges and imported materials can distort the comparison. A contingency should cover unknown work, not items that were simply omitted from the first estimate.
 
Because it is a new-build, separate handover defects from renovation work. Record cracks, leaks, uneven finishes, drainage issues and incomplete electrical points before anything is covered. If the building has a process for correcting defects, you do not want the renovation contractor pricing the same items without that distinction.
 
I would also ask the surveyor which walls may be altered, where shut-off points and access panels are located, and whether any proposed drilling affects shared services. Ask the contractor what remains provisional after inspection and what would require opening floors, ceilings or tiled walls.
 
Sequence it around the things that would destroy finished work: confirm services and allowable penetrations first, then any electrical and plumbing changes, waterproofing-related work, ceilings and walls, fixed joinery, flooring, and paint touch-ups. Do not let cabinetry fabrication begin from concept dimensions; require site dimensions after the relevant surfaces are established.
 
I’m not convinced a blanket 15% is automatically safer. A large reserve can hide a poorly defined tender. I would identify provisional amounts for electrical corrections, concealed plumbing and substrate repairs, then carry a smaller general reserve on top. That makes competing contractor prices easier to understand.
 
Moisture deserves its own investigation before cabinets or flooring go in. Have the wet areas, external-facing walls and likely pipe routes inspected, with existing marks photographed. Also ask how the contractor will distinguish an active water problem from residual construction moisture rather than covering either one with finishes.
 
Get every exclusion written beside the price: debris removal, protection of common areas, delivery restrictions, temporary water or power arrangements, access panels, making good after service work, testing, and return visits. Some may be included, but silence is where later arguments start. Material substitutions should also require approval rather than being treated as equivalent by default.
 
smallvictory_aya’s distinction is fair. I’d revise my earlier answer to a defined allowance for the unresolved service work plus a separate 10% general reserve, only increasing it while major items remain uninspected. Also ask which specified materials have long lead times before committing to the programme; delayed fixtures can leave several trades waiting.
 
For plumbing, confirm whether valves can isolate the flat without disrupting shared lines and whether traps, connections and drains remain accessible after installation. I would schedule a water test before closing access or installing adjacent joinery. That is more useful than discovering a slow leak after the flooring and kitchen are complete.
 
One missing fact could change all these answers: are the kitchen and bathrooms remaining in their original locations? Keeping sinks, drains and major electrical loads where designed is very different from moving them across the flat. If they are staying put, ask contractors to price relocation as excluded rather than leaving vague wording.
 
On electrical scope, ask for a clear list of existing points, proposed loads, distribution-board work, earthing observations and what testing is included after completion. “Electrical checks” is too broad for comparable bids. Any energy upgrades should also be itemised so they can be delayed without holding up essential remedial work.
 
Do not build the schedule solely around contractor availability. Ask building management what approvals, working hours, lift bookings, delivery arrangements and restrictions apply, and whether any part of the proposed work needs separate permission. The exact requirements are building- and jurisdiction-dependent, but their timing could affect procurement and the order of trades.
 
I would not choose between fixed-price bids and flexible allowances as if either approach works for the whole job. A fixed sum is useful for clearly defined rooms, but concealed plumbing or moisture work cannot be priced honestly until access is available.

Send every bidder the same layout, service information and room schedule. Ask them to separate firm work from provisional items, list all exclusions and lead times, and connect payments to finished stages. Put decorative upgrades on an optional list so that unresolved electrical or water work does not compete with them for the reserve.
 
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