Casos prácticos / Presupuestación y costos
Presupuestación y costos

Mantener la estimación de diseño dentro del presupuesto aprobado

Fija una estimación de inversión con un precio por metro cuadrado detrás, anota lo que supone, cotiza la estimación de diseño con el mismo alcance, y compárala contra la versión aprobada en cada hito.

5 pasos20 minDesarrollador / clienteConsultoría de costos / QSEstudio de diseño / ingenieríaGestora de proyectos / construcción

Cómo funciona, paso a paso

5 pasos a lo largo de la plataforma - qué haces en cada uno y por qué importa.

1

Set the investment estimate as a rate, not just a total

Estimación conceptual

Build the feasibility number from the building type, the gross floor area and the quality level, and read off the rate per square metre it implies as well as the total.

Por que: A total is a fact about a building nobody has designed yet, and a design team cannot work to it. A rate per square metre is a constraint they can test every decision against, which is the whole mechanism of cost-capped design, and it stays comparable when the area moves.

EntradaBuilding type and quality levelGross floor areaResultadoInvestment estimateRate per square metre
2

Write down what the approved number assumes

Bases de la estimación

Record the basis: the scope covered, the standard of finish, the price level and date, what is excluded, and where the rates came from. Keep it with the estimate rather than in the covering email.

Por que: Every argument at the next gate is about whether the design changed or the estimate was wrong, and only the basis can answer it. Without one, a stage that comes in over is always explained as a scope change, and there is nothing on either side that can contradict that.

EntradaThe approved numberWhat it assumedResultadoWritten basis of estimateExclusions on the record
3

Price the design estimate and name the version

Presupuesto

Price the design item by item against the same scope the basis describes, and save a named version of the bill at the moment it goes for approval so the approved state can be retrieved exactly.

Por que: The version that was approved is the only meaningful thing to measure later movements against, and it is unrecoverable a month afterwards unless somebody named it at the time. Naming it costs a moment and turns the next comparison from an argument into a report.

EntradaDesign as it standsThe stated basisResultadoDesign estimate priced by itemNamed version at the gate
4

Compare against the approved version at every gate

Presupuesto

Set the current bill against the version approved at the previous stage and read the difference by section: which items were added, which quantities grew, which rates moved. Work the rate per square metre out again on the current area and put it beside the one you started with.

Por que: Nothing here declares a limit or returns a verdict, and that is the honest shape of it: the product shows you where the money went and the cap is held by people. What makes that workable is running the comparison at each gate rather than once at the end, because a section that has grown by six percent is a design conversation while a total that has grown by twenty is a re-approval.

EntradaThe bill as it stands nowThe approved versionResultadoWhich sections movedThe rate per square metre now
5

Report the position with the movement explained

Informes

Report the stage total, the rate per square metre, the difference against the approved figure and the sections it came from, with a line on each saying whether it was a scope change, a design decision or a price movement.

Por que: An approving body asked to consider a number will ask where it came from, and a report that answers that in advance gets a decision instead of a deferral. Naming the cause per section is also what tells the design team where the savings have to come from, which is the only useful output of the exercise.

EntradaThe gate comparisonResultadoStage report for approvalWhere savings have to come from
Módulos

Módulos de este playbook

4 / 190 módulos de la plataforma

The market this case is written for

China

Everything in this case follows how construction work is measured, priced and paid for in this market. The forms, the cost breakdown and the payment rules are the ones used there, not a generic version of them.

Standards it follows

  • GB 50500
  • GB 50854

You do not have to set any of that up by hand. The first time you open the platform it asks which market you work in. Choose this one and it sets the interface language, loads the matching cost database and records the cost classification, and it adds an example project you can open straight away.

The rule checks for this market come with the platform too. Switch them on once and an estimate that misses something the market expects is flagged while you are still working on it, not after the tender has gone out.

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