How much contingency for renovating a 155 m² detached home in Seoul?

[bikesAndEcho]

I have checked that the planned work does not include an extension, but the condition behind the finished surfaces is still unclear. The Seoul house is detached, measures 155 m² and is being purchased for ₩462,300,000. I am testing ₩69,360,000 as the renovation budget for the kitchen, wet areas, surfaces, wiring assessment and some energy improvements.

As a first-time renovator, I see two different risks: keeping too little in reserve could stop the job after demolition, while holding a large contingency will not rescue a scope built on weak assumptions. Before fixing the price, I plan to request moisture readings, details of pipe access, the precise extent of electrical work, and a list separating firm items from provisional sums and exclusions. What level of the budget should remain uncommitted until opening-up work is complete?

 

[DaanGale]

For an older detached house with several wet areas involved, I would keep roughly 15–20% of the renovation allowance uncommitted until opening-up work is complete. Ask contractors to separate visible work from provisional items: wiring replacement, damaged pipes, waterproofing repairs, rotten substrate and any structural remediation discovered after demolition. Also ask exactly what “electrical checks” includes; inspection and full replacement are very different costs.

 

[sharp_frame]

I’m not convinced a larger contingency fixes the main problem if the ₩69,360,000 scope is still broad. Do you know the building’s age, previous renovation history, and whether supply and waste pipes can be reached without removing finished floors or walls? Moisture readings around bathrooms, roof edges and the lowest level could change the sequence substantially. I’d want intrusive inspection where permitted before accepting a fixed quotation.

 

[fast_moss]

Have each bidder submit a room-by-room scope plus an exclusions list, not just one total. Then compare who includes demolition, disposal, substrate repair, waterproofing, testing and reinstatement. Before signing, map the order: investigation, any permit-dependent work, demolition, plumbing/electrical corrections, moisture drying, finishes and final testing. Confirm material lead times separately so the kitchen or bathroom order does not leave opened rooms waiting while labour costs continue.