Contingency and hidden-condition planning for a 240 m² Bangkok renovation

[SharpPost]

Access to hidden services may determine the contingency more than the finish specification. That is my main concern for a 240 m² small multifamily renovation in Bangkok, currently budgeted at THB 13,150,000.

The plan covers kitchen and washroom renewal, new floor finishes, decoration, investigation and remedial work to the electrical installation, plus limited energy improvements. There is no extension. Before adding a percentage to the budget, I would like to reduce the uncertainty around pipe routes, damp areas and wiring concealed behind completed surfaces.

Which areas would you open up or survey before tender, and what exclusions should each contractor be required to price clearly? I am also wondering whether material lead times or permit timing should be settled before agreeing the work sequence.

 

[holdTheEcho]

At this stage I’d provisionally carry about 15%, but divide it into two pots: hidden building conditions and client changes. Before tendering, ask for moisture investigation around wet areas, an assessment of accessible electrical panels and wiring, and a clear list of everything the contractor excludes. If those findings are poor, revise the base scope rather than quietly consuming the contingency.

 

[RightRoom]

Will the units be vacant during the work? That changes the sequence and possibly the temporary-service costs. I’d also want to know whether kitchens and bathrooms share accessible plumbing routes or whether walls and floors must be opened separately in each unit. Building age and records of previous alterations would help frame the electrical questions.

 

[timo.grove]

I’m less comfortable attaching 15% before any selective opening-up. A percentage can give false reassurance when the main risks are still undefined. With permission, inspect representative bathroom and kitchen service zones, ceiling voids and accessible drainage routes first. Also make each bidder state assumptions about making good, debris removal, temporary protection, permit responsibility and waiting time. Those exclusions often explain why apparently similar bids are not comparable.

 

[jazzAndWorkshop]

For sequencing, settle service routes and wet-area repairs before flooring and paint. Ask bidders for a programme that identifies decisions and materials with long lead times, plus acceptable substitutions if an item would delay several units. If the property stays partly occupied, request a unit-by-unit plan showing shutdowns, access needs and how completed areas will be protected.

 

[yogaAndLens]

I’d turn the THB 13,150,000 estimate into a room-and-system schedule before deciding the final reserve. Separate kitchens, bathrooms, electrical, plumbing, moisture repairs, finishes and energy work, then note quantities, assumptions and exclusions beside each line. Tenderers can price the same scope and flag gaps instead of burying them in a lump sum. Keep contingency outside the contract price initially, and require written pricing and schedule effects before drawing from it.