- +6.8%
- year-on-year new housing construction costs, July 2026
- +22.8%
- average overrun among UCI study cases that exceeded budget
- 414 days
- average planned construction time in the UCI study
The more you decide before construction starts, the less you improvise during the build.
The project did not simply become expensive at the end. It may have started underdefined.
When a project starts with one budget and finishes significantly above it, it is easy to assume that “construction is always like that”. Not necessarily.
Some factors are difficult to control. Material prices change, labour costs rise, suppliers can be delayed and conditions may only become visible after work begins.
But some overruns start much earlier. They start with “we will decide later”, with a material that has not yet been selected, with a change requested after a team has already started, or with a seemingly small decision that forces completed work to be revisited.
The current context makes preparation even more important. In July 2026, the cost of new housing construction in Portugal was 6.8% higher than a year earlier. Statistics Portugal estimated a 6.3% increase in material prices and a 7.3% increase in labour costs. When underlying construction costs are already rising, improvisation becomes even more expensive.
How far can budgets overrun?
A study published by UCI with Spirituc examined the experience of 611 people who had built a home in the previous two years. It is not representative of every construction project in Portugal, but it provides a useful view of recent private-client experiences.
Among the 301 respondents who had completed their build, 86.4% said the planned budget had been met. In the cases where it had not, the average overrun was 22.8%. The most frequently cited reasons included inflation-driven price increases, mentioned by 56.1% of respondents with overruns, and changes to the original design, mentioned by 46.3%.
That last figure matters because a change rarely means simply buying a different product. It may mean removing completed work, relocating services, placing a new order, remobilising a trade or delaying activities that depend on the decision.
And what about time?
In the same study, the average planned construction period was 414 days — roughly 14 months — and 85% of respondents said that timeline had been met. Among projects delivered late, the average delay was 164 days.
Late material deliveries were cited in 46.7% of delayed cases and labour shortages in 26.7%. Some delays therefore come from the market. Others are created inside the project itself.
Imagine flooring is scheduled to start in a particular week, but the product has still not been selected. The team waits. The order goes in late. The supplier quotes four weeks. Skirtings depend on the flooring. Door levels depend on finished floor build-up. Other finishes are held back. One late decision can create a chain of delays.
Deciding early does not mean nothing can change
A well-prepared project does not eliminate unforeseen conditions. Promising that would be unrealistic. The goal is different: do not turn something that could have been decided in advance into an “unexpected” issue.
Before construction begins, the layout, principal technical solutions, major materials, equipment, finishes, scope and responsibilities should be sufficiently defined. The fewer grey areas there are, the more reliable the budget and programme can be.
A good project is not one where nothing changes
It is one where everyone can quickly understand what changed, why it changed, what the impact is, what the alternatives are and who needs to decide.
Planning, budget and communication are not separate subjects. They are part of the same process.
