Factors taken into account when applying prices

The prices used in drawing up the bill of quantities take into account various factors that directly or indirectly influence the final cost of the project. These are categorised as geographical, socio-economic, typological, construction-related, and climatic and seismic factors.

Geographical factors

These are factors related to the geographical and climatic conditions of the area, which are intrinsically linked to the socio-economic factors that affect labour costs and productivity, notably:

• Population density
  Influences supply and demand and, therefore, market prices.
• Tourism development in the area
  Increases demand and the purchasing power of local residents.
• Condition and development of transport infrastructure
  Influences the cost of distributing and transporting materials, goods and services.

Socio-economic factors

These are factors that depend on the economic, political and social situation in each area and which influence the cost of materials, labour and machinery; these include the following:

• Net monthly salary in the construction sector
  Influences labour costs.
• National minimum wage
  Influences labour costs.
• Gross national income (GNI) per capita (purchasing power parity, PPP)
  Influences prices in general.
• Inflation rate
  Leads to a sustained increase in prices.
• Unemployment rate
  Reflects the availability of labour and, therefore, hiring costs.
• Exchange rate
  Particularly affects imported goods and services.
• Market conditions
  Indicate the relationship between supply and demand in the procurement of materials, the hiring of labour, and the rental of equipment and machinery used in the construction process. This does not refer to supply and demand in the real estate market, but rather to contractor demand, material supply, and the labour market.
• Imports of goods and services
  Influence the prices of imported materials.
• Industrial production growth rate
  Reflects the availability of auxiliary means that facilitate construction activities.
• Corruption Perceptions Index (CPI)
  Indirectly affects prices in general: the higher the level of corruption, the higher the construction costs.
• Human Development Index (HDI)
  An indicator of health, education and economic level, reflecting the competitiveness and productivity of the population, and therefore directly influencing construction performance and final costs.

The adjustment coefficients associated with each socio-economic and geographical factor have been quantified through the study and analysis of data provided by recognised statistical sources, such as the World Bank, the European Commission, Datos Macro Expansión, IndexMundi, Preciosmundi and XE Live Exchange Rates.

Typological factors

• Gross floor area
  Affects both costs and labour productivity.
• Building use
  Involves specific construction solutions and building services and, therefore, affects the overall building cost.
• Number of floors above ground level
  Building height entails more complex and costly structural and construction solutions, while also making vertical movement more difficult, which reduces productivity.
• Number of floors below ground level
  The construction of basements introduces additional complexity that affects construction costs, particularly in the earthworks and foundations trades.
• Average floor-to-ceiling height
  Directly influences the building volume, especially in the external walls, partitions and finishes trades. It also increases vertical movement, leading to reduced productivity.
• Building typology
  Affects the floor plan configuration and façade area and, therefore, the construction cost.
• Complexity of the floor plan geometry
  Influences the building cost, as it generally reduces productivity.
• Percentage of openings in façades
  Openings in façades increase their cost.
• Degree of internal partitioning
  Affects the cost of partitions, joinery and internal finishes.
• Accessibility
  Refers to site access conditions and the возможности for storing materials outside the building plot.
• Site topography
  Assesses the difficulty caused by level differences within the site, which affect the productivity of machinery and labour.
• Quality level
  This is intrinsically linked to the total construction cost. The program allows the quality level to be selected independently for the building as a whole, the construction systems, and the building services.
  The quality level is defined according to the characteristics of the materials, equipment and construction processes used on site, based on the following criteria:
  • Basic
    They strictly comply with current regulations. Their cost falls below the 30th percentile of the overall market price range.
  • Medium
    They exceed the minimum requirements set out in current regulations and add further quality to the building as a whole. Their cost falls within the range defined by the 30th–70th percentiles of the overall market price range.
  • High
    They comfortably exceed the minimum requirements set out in current regulations and represent a significant improvement in the quality of the building as a whole. Their cost is above the 70th percentile of the market price range.

Construction factors

Depending on the selected use, the program sets the standard units of work that make up the various sections of the estimate:

• Ground conditioning
• Foundations
• Structure
• External walls
• Roof
• Partitions
• Facilities
• Cladding
• Signage and equipment
• Environmental management, monitoring, health and safety

You can change the default settings that the program offers for each use.

Climatic and seismic factors

The program also takes into account these other factors that affect the building’s bill of quantities:

• Thermal conditions
  The external temperature influences the design and sizing of the building envelope and its heating and cooling systems, particularly the cost of insulation and external joinery.
• Wind speed
  The dynamic wind pressure determines the design, dimensions and cost of the structure and external joinery.
• Degree of exposure to wind
  This has an impact on the cost of the structure and external joinery, particularly in buildings located near cliffs, the seashore, or open countryside, amongst others.
• Seismic risk
  Seismic forces influence the design and dimensioning of the foundations and the structure. They therefore affect the final cost of the building.