Cost control in construction is one of the most critical activities in project management. Many Spanish construction firms discover cost overruns when it is already too late to take corrective action. This article guides you through the fundamental principles of cost control and provides you with the tools to keep your projects within budget.
What is cost control in construction?
Cost control is the process of monitoring, recording, and analyzing the actual costs of a construction project and comparing them to the approved budget. It is not simply accounting, but an ongoing activity of oversight and decision-making to ensure that costs do not exceed the established limits.
Effective cost control allows you to:
- Detect deviations early before they become significant losses
- Identify the root causes of cost overruns in order to learn and improve
- Take corrective action before the project closes
- Meet profitability commitments with developers and shareholders
- Improve budget accuracy on future projects
Cost structure in construction
To control costs, you must first understand how they are structured. A construction project has two main cost categories:
DIRECT COSTS Direct costs are those attributable directly to a specific line item or work concept:
Direct labor: The cost of workers assigned to specific site tasks. Recorded through work orders and charged to the corresponding budget line item. Includes day laborers, tradespeople, and specialists.
Materials: Concrete, steel, ceramic, paint, electrical components. Each material is linked to the line item where it is consumed. Requires inventory control and traceability from purchase through to consumption.
Subcontracts: The cost of subcontracted work — steel structures, electrical installations, plumbing. Controlled through supplier contracts and delivery notes.
Machinery and equipment: Cranes, scaffolding, formwork, tools. These may be rented (cost per day) or depreciated (cost of ownership).
INDIRECT COSTS Indirect costs are expenses necessary for project execution but not assigned directly to a specific line item:
- Technical office staff: Site management personnel, surveyors, quantity surveyors
- Insurance and guarantees: Public liability, project insurance, mandatory policies
- General transportation: Not assigned to any specific line item Energy, water, and site utilities
- Permits and licenses: Municipal licenses, fees, inspections
Committed cost VS actual cost VS forecasted cost
For effective cost control, you must understand three fundamental concepts:
**Forecasted cost **This is the original approved budget for each line item. It is the cost target you set when you won the project.
Example: For the line item "Concrete structure," you budgeted €250,000.
**Committed cost **This is the cost you have already incurred through contracts, purchase orders, and formal commitments, even if you have not yet received the invoice. It represents your payment obligation.
Example: You issued a subcontract to the structural contractor for €260,000 (you have already committed more than budgeted).
**Actual cost **This is the cost actually paid or accrued (invoice received and recorded in accounting), regardless of whether payment has been made.
Example: You have received invoices for €280,000 in materials and labor for the structure.
The control equation: Forecasted cost → Committed cost → Actual cost
If you detect that the committed cost already exceeds the budget, you still have time to act. If you wait until the actual cost, it may be too late.
Control indicators: The CPI (Cost Performance Index)
The CPI is an earned value metric that tells you whether you are running over or under budget. Its calculation is:
CPI = Earned Value / Actual Cost
CPI > 1.0: Better than budgeted (profitable) CPI = 1.0: Exactly on budget CPI < 1.0: Worse than budgeted (loss)
Practical example:
Structure budget: €250,000 Physical progress: 60% Earned value (60% of €250,000): €150,000 Actual cost incurred to date: €180,000
CPI = 150,000 / 180,000 = 0.833
This means that for every euro of work completed, you have spent €1.20. You are 16.7% over budget.
Structure of a cost control system
A cost control system on site must include these elements:
1. Budget structured by line items
The budget must be broken down into line items that are sufficiently detailed to allow cost allocation. A budget with 5 lines is not useful; you need at least 30–50 line items for granular control.
2. Real-time cost recording
Every cost (purchase order, delivery note, invoice, work order) must be recorded and allocated to the corresponding line item. Delays in recording create gaps between actual and budgeted costs.
3. Periodic comparison
Every week or every two weeks, you should generate a budget vs. actual comparison to identify which line items are deviating.
4. Cause analysis
When you detect a significant deviation, you must investigate:
- Changes in work quantities
- Changes in specifications
- Labor inefficiencies
- Material price increases
- Changes in construction method
5. Corrective actions
Once the cause is identified, implement actions:
- Renegotiate supplier contracts
- Optimize labor productivity
- Change specifications pending developer agreement
- Source alternative materials
- Reformulate the construction method
Corrective actions when deviations are detected
When your CPI shows you are running over budget, you have several options:
Option 1: Renegotiate with suppliers If you find that a subcontract is going to cost 20% more than budgeted, contact the supplier to renegotiate.
Option 2: Optimize labor If labor costs are higher than planned, analyze productivity improvements and reorganization.
Option 3: **Request variations from the developer **If the deviation is due to scope changes, document the additional work and request a price variation.
Option 4: **Absorb into margin **If the deviation is small, it may be better to absorb it than to generate delays.
Common deviation cases in Spain
- Unforeseen work due to ground conditions Action: Document and request a work variation
- Regulatory changes Action: Define in the contract who absorbs regulatory changes
- Material price increases Action: Revision clauses and forward purchasing
- Low labor productivity Action: Replanning and improved coordination
- Initial quality deficiencies Action: Rigorous quality control from the outset
Cost control best practices
- Segregate responsibilities
- Use integrated software
- Review CPI monthly
- Link purchase orders to line items
- Validate delivery notes on site
- Maintain a change history
How Trowel helps you with cost control
Trowel is designed specifically for Spanish construction companies. In the project economic plan module you can:
- Load the budget
- Link purchase orders, delivery notes, and invoices
- Record work orders
- View comparisons in real time
- Identify deviations
- Export reports
It also allows you to manage purchasing, contracts, invoicing, and reports with full control over committed and actual costs.
Request a Trowel demo and discover how to improve cost control on your projects.
