Contingency and hidden risks in a NOK 2.522m Oslo renovation

[LivPike]

I’ve now capped the working budget at NOK 2,522,000, which raises a harder question: for a 230 m² coastal home in Oslo, how much of that sum should remain uncommitted until work begins?

The plan covers kitchens, wet rooms, floors, decoration, an assessment of the electrics and some energy-efficiency work. There is no extension. If the bathrooms and wiring can be properly investigated before signing, I could use a smaller reserve; if access is limited or the contractor leaves major items provisional, I would hold back considerably more. What investigations, written exclusions and permit milestones would you insist on before choosing between those two approaches?

 

[AmberPost]

I would start around 15% contingency and consider 20% if the wet rooms have not been opened up or the electrical scope is still described only as “checks.” Ask contractors to price the known work separately from provisional items, and to list every exclusion in writing. I’d also want moisture investigation around bathrooms and exposed coastal elevations before locking the schedule.

 

[AshaLane]

Are the bathrooms complete rebuilds, and will the house be occupied during the work? Those two details could change both sequencing and cost. Plumbing access matters too: accessible runs are one thing, but opening finished floors or ceilings to reach them can spread work into rooms that currently look unaffected.

 

[AshaLane]

If the unknown work is priced as though it were already defined, the reserve could disappear before the main renovation is under way. I would divide the NOK 2,522,000 into fixed items, realistic allowances and genuinely concealed risks rather than rely on one percentage.

The programme matters just as much. Ask for the sequence by room, including opening-up work, plumbing, electrics, drying time, inspections and finishes. Permit ownership and order-by dates should also be settled before demolition. If approvals and supplies are confirmed, more money can remain in the construction pot; if either is uncertain, protect both the contingency and the schedule.