The typical building structure
The canonical order follows the construction sequence:
| Chapter | Summary content |
|---|---|
| Preliminary works and demolition | Only in renovation or occupied plots |
| Earthworks | Excavation, fills, haulage |
| Foundations | Footings, slabs, piles, basement walls |
| Structure | Concrete, steel or timber; floors and stairs |
| Masonry and enclosures | Façades, partitions, builder's assistance |
| Roofing | Waterproofing, insulation, finish |
| Building services | Drainage, plumbing, electrical, climate, telecommunications, fire protection |
| Insulation and waterproofing | Where not integrated into their elements |
| Coverings and finishes | Flooring, tiling, ceilings, painting |
| Joinery and metalwork | External and internal, glazing |
| External works | Plot exteriors |
| Waste management, quality control, health and safety | Final regulatory chapters |
Reference price databases provide codified chapter structures ready to inherit; adopting them gives free comparability between projects and with sector statistics. Inventing a bespoke structure means translating it back at every later comparison.
Usual weights as a tool
For a standard multifamily building, the orders of magnitude on the PEM serve as a coherence test: foundations 5-12 %, structure 15-22 %, façades and roofing 12-18 %, services 15-22 %, finishes and joinery 20-28 %. A chapter out of range is not necessarily an error, but it is always a question: services at 8 % announce omissions; finishes at 35 % announce a quality level that should also be readable in the rest of the document. The same test, applied to an offer, detects unbalanced prices before any item-by-item reading.
Three chaptering rules
Stable construction order. The budget is read as it is built; improvised thematic chapters break comparability.
Every work in a single chapter. Builder's assistance to services is the classic case: it is placed by declared convention (in masonry or distributed), never in both places nor in neither.
Sub-chapters only with purpose. Breaking services down by trade aids reading; breaking painting down by colour does not. Every level of detail is paid for in document maintenance.
The essentials
Chaptering is the budget's reading interface: construction order, a chapter structure inherited from the reference database where possible, and usual weights used as a systematic coherence test. With that discipline, the chapter fulfils its double function: making the document legible and making anomalies visible. The rules that fill this structure with quantities are covered in measurement rules.
Note: indicative structure and weights for building construction in Spain in 2026; each project adapts its chaptering.