Metric calculations

Il estimated metric calculation It is the document that allows you to define the cost of building a building.
In its most basic form it consists of a five-column table formed by: order number, description of the work, number, dimensions (length, width and height), weight, unit of measurement, products (negative, positive and total), unit price, amount and figures and annotations. The correct and precise drafting of a metric calculation requires first of all an order in its execution. The works that make up the work are reported in the order in which they follow one another for their execution; therefore, for building works, it is possible to stick to the following list:

Estimate works computed full to empty
Excavation and earthmoving work.
Structural works.
Masonry works.
Finishing works.
Works in wood or iron.
Technological systems.
Equipped spaces.

The units of measurement in the various categories are different in relation to the type of work, considering that the various quantities of work are always determined according to their geometric characteristics; the following criteria can be followed as a guide:
They are valued per cubic meter:

Excavations of any kind based on the actual volume of earth that needs to be excavated.
The embankments and backfills.
Walls in general, i.e. with a thickness equal to or greater than 15 cm, generally deducting only voids with a surface area greater than 1,00 m2.
The entire structure is in reinforced concrete, including the slabs and stair ramps.

They are valued per square meter:

Walls with a thickness of less than 15 cm, generally deducting only the voids with a surface area greater than 2,00 m2
Internal and external coverings and floors.
Mixed floors with reinforced concrete beams and bricks.
The roof coverings.
The plasters.
The stone slabs.
Glass and crystal according to the dimensions in operation.

They are valued per linear metre:

Gutters and downpipes.
Pipes as long as they are not made of cast iron or steel.
Frames and decorations.
Railings and handrails.
Skirting boards.

They are valued by weight:

Steel for reinforced concrete works
Lead, steel, copper sheets used in roofing.
Cast iron and steel pipes.
Generally all metal works (doors, cases, brackets etc.)

The product of the quantity and the unit price defines the total amount of the single expense. The sum of the individual expense items defines the construction cost incurred for the construction of the work.
The definition "estimative" indicates that the data of the metric calculation are also used to achieve the purposes of appraisal, that is, to identify the value of those assets (generally buildings and companies) for which there are no univocal market prices. It should also be said that there are two types of metric calculation:

final bill of quantities: this is the one drawn up after the operation;
preventive metric calculation: this is what is drawn up before the operation

Source: Wikipedia