The output: the decisive multiplier
The output expresses the hours of each trade grade needed per unit of work. Its effect is direct: in labour-intensive items (partitions, coverings, building services), 20 % variations in output move the price more than any materials negotiation.
The outputs published by databases assume average conditions: a clear site, normal series, accessible work areas. Real conditions correct in both directions:
| Condition | Typical effect on output |
|---|---|
| Occupied renovation or fragmented work areas | Noticeable penalty: more hours per unit |
| Working heights, difficult access | Penalty through equipment and travel |
| Long, repetitive series | Improvement: the learning curve reduces hours |
| Prefabrication and industrialisation | Moves hours from site to workshop: it changes the structure, not just the number |
Professional adjustment is not a uniform percentage across the whole budget but a directed correction to the item families affected by each condition. And the best source of outputs remains the in-house history: timesheets from comparable projects are worth more than any published table.
Auxiliary prices: the reusable pieces
An auxiliary price is an intermediate composition (a mortar, a grout, a levelling paste) that enters as a component in many breakdowns. Its function is coherence and maintenance: the mortar is defined once, with its materials and mixing, and every breakdown using it inherits any update.
The associated discipline is simple: auxiliaries are updated in their single definition, never patch by patch in each item, and their components (cement, sand, water, and the fabrication labour where applicable) follow the same adaptation rules as the rest of the system. An auxiliary patched in one item and not the others produces prices inconsistent across chapters.
The hourly cost: the product's other half
The output multiplies an hourly cost per grade (first-grade officer, second-grade, labourer), and that cost comes from the applicable provincial collective agreement plus the associated employer costs. Two checks avoid systematic errors: the agreement's consistency with the project's province, and updating to the current year, because agreements are revised and databases can run a year behind.
The essentials
The output decides the price of labour-intensive items and is adjusted for execution conditions, family by family, with the in-house history as the best source. Auxiliaries give the system coherence provided they are maintained in their single definition. And the hourly cost is anchored to the current provincial agreement. With those three pieces calibrated, the breakdown stops being a template and starts describing the real project.
Note: usual practices in Spain in 2026; agreements and hourly costs vary by province and year.