Contingency and hidden risks for a €133,600 renovation of 150 m² in Madrid

[trackTheWindow]

The first budget pass has come out at €133,600, which raises a new question: how much of that figure is genuinely priced rather than assumed? It covers renovation of a 150 m² small multifamily in Madrid, including kitchens, bathrooms, floors, decoration, an electrical review and some energy-efficiency work. There is no extension in the plan.

Before setting the contingency, I want to pin down electrical scope, moisture or access problems, contractor exclusions and the effect of permit timing. What investigations would you commission before tendering, and which costs should sit outside the construction budget altogether?

 

[LocalTrail]

I would initially keep about 15% outside the €133,600, then adjust after opening-up investigations and detailed tenders. Ask every contractor to list exclusions, not just inclusions. The dangerous gaps are usually described vaguely: electrical “checks,” making good after plumbing access, moisture treatment, waste removal and work affecting shared parts of the building.

 

[RightRoom]

Is the building vacant, and does 150 m² mean one dwelling or several units? Sequencing becomes much harder if kitchens and bathrooms cannot all be unavailable together. Also, does €133,600 include design fees, permit-related costs and tax, or is it construction only? Without those answers, a contingency percentage may hide an incomplete base budget.

 

[BrightStone]

I’d separate unknown conditions from omitted scope. Contingency can absorb concealed damage, but it should not fund items that could have been defined beforehand. Before tender, I’d want moisture readings around wet rooms and external walls, an assessment of accessible drains and supply pipes, and a written description of what the electrical inspection will actually cover.

 

[BrightStone]

Material timing also belongs in the programme rather than the contingency. Identify anything that needs measurement after demolition, and anything that must be selected early. Otherwise the contractor may either pause between trades or make assumptions about sizes and substitutions. Kitchens are an obvious sequencing point, but bathroom fittings, flooring transitions and energy-upgrade components can also hold up closing works.

 

[LocalTrail]

On reflection, 15% could give false comfort if “electrical checks” is still the full description. Does the price allow only inspection and testing, or replacement where problems are found? Ask for separate rates or provisional allowances for likely remedial work. Then the reserve is covering genuine surprises rather than an undefined electrical package.

 

[round_horizon]

Plumbing access deserves its own conversation. Ask where pipes can be reached, which walls or floors would need opening, and who pays for reinstatement. In a small multifamily, also establish which runs serve only the renovated space and which may be shared. That responsibility should be clarified from the building information and local advice before demolition starts.

 

[BrightStone]

For comparable tenders, I’d issue the same questions to each bidder: what is excluded, what assumptions were made about substrate condition, how many site visits are included before pricing, who coordinates the trades, and what happens when concealed work is discovered. Require a priced written change before extra work proceeds, except where something genuinely needs urgent protection.

 

[BrightStone]

Permit timing should be shown as a dependency, not buried inside the contractor’s start date. Confirm which parts of the proposed scope need approval in Madrid and whether any shared-building consent is relevant. I wouldn’t order a full crew for demolition until those points and site access are clear. The exact requirements depend on the works, so this is one for the project’s local advisers.

 

[fast_compass]

There is a trade-off with opening-up surveys: they reduce uncertainty but create damage and disruption before the main contract. If the property is occupied, target the highest-risk locations rather than opening everything. Wet-room service routes, suspicious staining, the electrical intake and representative floor or wall build-ups would tell you more than a broad visual inspection alone.

 

[LocalTrail]

A workable sequence might be: investigations and scope definition; approvals and long-lead selections; isolations and controlled strip-out; plumbing and electrical work; energy measures; closing and waterproofing; then finishes, kitchens and final testing. The contractor should mark which stages need inspection before they are covered. That schedule will expose conflicts much earlier than a simple completion date.

 

[sharp_journal]

At 15%, the reserve would be €20,040, held by the owner rather than automatically added to the contractor’s spend. I might carry more until the electrical, moisture and plumbing questions are answered, then reduce it only if the surveys and tenders genuinely remove uncertainty. A large reserve is not a substitute for a complete scope or firm exclusions.

 

[candid_ridge]

Don’t let “no structural extension” turn into “no structural risk.” Removing finishes, chasing services or changing bathroom layouts can still reveal or affect the existing fabric. Ask the surveyor to flag any proposed openings or concentrated loads that need closer consideration. The contractor should also state what happens if demolition exposes cracking, rotten material or persistent moisture rather than pricing an assumed repair.

 

[BrightStone]

The useful next step seems to be a short pre-tender risk schedule: issue, investigation, person responsible, allowance and latest decision date. I’d put electrical remedials, plumbing access, moisture, shared elements, permits and long-lead materials on it first. Once those are answered, compare the €133,600 tenders on identical scope and exclusions, then set the final contingency from the remaining unknowns rather than choosing a percentage in isolation.