Concepts & Line Items#

Note

Spanish Term: Concepto

Understanding concepts (individual work items) in Construbot contract catalogs.

What is a Concept?#

A Concept (Spanish: Concepto) is an individual work item in a construction contract catalog. Concepts represent:

  • Specific types of work to be performed

  • Measurable units of construction activities

  • Line items for billing and tracking

  • Building blocks of estimates

Model: construbot.proyectos.models.Concept

Key Relationship: Concepts belong to a contract and define what work will be done, at what quantity, and at what price.

Concept Structure#

Basic Information#

Required fields:

  • Code (clave) - Unique identifier within contract catalog

  • Description (concepto) - Description of the work

  • Unit (unidad) - Unit of measurement

  • Quantity (cantidad) - Total contract quantity

  • Unit Price (precio_unitario) - Price per unit

  • Contract (contrato) - Parent contract

Optional fields:

  • Notes (notas) - Additional specifications

  • Category (categoría) - Grouping for organization

  • Order (orden) - Display sequence

  • Active (activo) - Whether concept is currently used

Calculated fields:

  • Total (importe) - Quantity × Unit Price

Example Concept#

Code: 001-EXC-01
Description: Excavation for foundations, including hauling
Unit: m³ (cubic meter)
Quantity: 500.00
Unit Price: $200.00
Total: $100,000.00

Category: Earthwork
Notes: Depth 0-3 meters, hard soil conditions

Units of Measurement#

Common Units#

Construbot supports various measurement units:

Linear measures:

  • m - Meter

  • km - Kilometer

  • ft - Foot

Area measures:

  • m² - Square meter

  • ft² - Square foot

Volume measures:

  • m³ - Cubic meter

  • L - Liter

Weight measures:

  • kg - Kilogram

  • ton - Metric ton

Count measures:

  • pza - Piece (Spanish: pieza)

  • u - Unit

  • lot - Lot (complete set)

Service measures:

  • hr - Hour

  • day - Day

  • month - Month

Model: construbot.proyectos.models.Units

Custom Units#

Add custom units as needed:

  1. Navigate to Units management

  2. Create new unit with abbreviation and description

  3. Use in concept catalog

Creating Concepts#

Method 1: Manual Entry#

Step 1: Access Contract Catalog#

  1. Navigate to the contract

  2. Find “Concepts” or “Catálogo de Conceptos” section

  3. Click “Add Concept” or “Agregar Concepto”

Step 2: Enter Concept Details#

Code: 002-CONC-01
Description: Concrete f'c=250 kg/cm² for foundations
Unit: m³
Quantity: 120.00
Unit Price: $1,500.00

Category: Concrete Work
Notes: Includes formwork and reinforcement steel

Step 3: Save#

Click “Save” to add this concept to the catalog.

Repeat for all concepts in the contract.

Method 2: Excel Import#

For large contracts with many concepts:

Step 1: Prepare Excel File#

Create spreadsheet with columns:

Code, Description, Unit, Quantity, Unit Price, Category, Notes
001-EXC-01, Excavation for foundations, m³, 500, 200.00, Earthwork, Depth 0-3m
002-CONC-01, Concrete f'c=250, m³, 120, 1500.00, Concrete, With formwork

Step 2: Import to Construbot#

  1. Navigate to contract concepts section

  2. Click “Import from Excel” or “Importar desde Excel”

  3. Select your prepared file

  4. Map columns (if not auto-detected)

  5. Review and confirm import

Benefit: Quickly populate catalog with dozens or hundreds of concepts.

Method 3: Copy from Template#

If you have standard catalogs:

  1. Create “template” contract with common concepts

  2. When creating new contract, select “Copy catalog from…”

  3. Choose template contract

  4. All concepts copied to new contract

  5. Edit quantities and prices as needed

Use case: Repetitive project types with similar work items.

Catalog Organization#

Concept Codes#

Use structured coding system for organization:

Format: [Category]-[Subcategory]-[Sequence]

Examples:

001-PREP-01: Site preparation
001-PREP-02: Demolition
002-EARTH-01: Excavation
002-EARTH-02: Backfill
003-CONC-01: Foundation concrete
003-CONC-02: Column concrete

Benefits:

  • Easy sorting and grouping

  • Quick reference

  • Professional appearance on documents

Categories#

Group concepts into categories:

  • Preliminary Work: Site prep, mobilization

  • Earthwork: Excavation, compaction

  • Concrete Work: Foundations, slabs, columns

  • Masonry: Block walls, brick veneer

  • Finishes: Flooring, painting, trim

  • MEP: Mechanical, electrical, plumbing

Purpose: Organize large catalogs, generate category subtotals.

Display Order#

Use the Order field to control sequence:

  • Lower numbers appear first

  • Group related concepts together

  • Match typical construction sequence

Using Concepts in Estimates#

Concept Selection#

When creating an estimate:

  1. Choose concepts from contract catalog

  2. Enter quantity completed this period

  3. System uses unit price from catalog

  4. Calculate line item subtotal automatically

Example:

Estimate #3 - March 2024

Concept: 002-CONC-01 - Concrete f'c=250
Contract Quantity: 120 m³
Contract Unit Price: $1,500/m³

Previous Estimates: 80 m³
This Estimate: 30 m³
Cumulative: 110 m³
Remaining: 10 m³

Line Item Total: 30 m³ × $1,500 = $45,000

Quantity Tracking#

Construbot tracks for each concept:

  • Contract Quantity: Original scope

  • Billed to Date: Cumulative from all estimates

  • Remaining: Contract - Billed

  • Over/Under: If billed exceeds contract

Status Indicators:

  • ✓ Complete (100% billed)

  • ⚠ Over-billed (>100%)

  • ◷ In Progress (<100%)

  • ○ Not Started (0%)

Price Changes#

Unit Price Adjustments#

If unit price needs to change:

Option 1: Change Order

  1. Create formal change order

  2. Update concept unit price

  3. Document reason in notes

  4. Get client approval

Option 2: New Concept

  1. Keep original concept as-is

  2. Create new concept with adjusted price

  3. Use for future estimates

Best Practice: Document all price changes with change order references.

Quantity Adjustments#

If contract quantity changes:

Increase Quantity:

  1. Update concept quantity

  2. Document change order

  3. Difference becomes additional scope

Decrease Quantity:

  1. Update concept quantity

  2. Adjust estimates if needed

  3. Credit or reduce billing

Hierarchical Contracts#

Concept Inheritance#

For parent-child contract structures:

Parent Contract:

  • Contains high-level concepts

  • Rolled-up quantities and prices

  • Summary-level tracking

Subcontract:

  • Detailed breakdown of parent concepts

  • Independent catalog

  • Separate tracking

Relationship: Subcontract concepts can reference parent concepts for rollup reporting.

Best Practices#

1. Use clear, descriptive descriptions:

GOOD: "Concrete f'c=250 kg/cm² for foundations, including formwork and reinforcement"
BAD: "Concrete"

2. Include specifications in description:

Key details like:

  • Material grades

  • Installation methods

  • Included components

3. Consistent unit usage:

GOOD: All excavation in m³, all concrete in m³
BAD: Some excavation in m³, some in loads

4. Logical code structure:

Use systematic coding for easy reference.

5. One concept = one measurable item:

GOOD:
- Excavation (m³)
- Concrete (m³)
- Reinforcement (kg)

BAD:
- Excavation including concrete and rebar (lot)

6. Price verification:

Before importing or saving:

  • Verify unit prices match contract

  • Check decimal places

  • Confirm total calculations

7. Regular catalog review:

  • Remove unused concepts (mark inactive)

  • Update prices for escalation

  • Correct errors promptly

Common Scenarios#

Scenario 1: Standard Building Contract#

Setup:

  • 50 concepts across 8 categories

  • Mix of quantities (m³, m², kg, pza)

  • Total contract value $2,000,000

Catalog Structure:

001 - Preliminary Work
   001-PREP-01: Mobilization (lot)
   001-PREP-02: Site clearing (m²)

002 - Earthwork
   002-EARTH-01: Excavation (m³)
   002-EARTH-02: Compaction (m³)

003 - Concrete Work
   003-CONC-01: Foundations (m³)
   003-CONC-02: Columns (m³)

[... continued ...]

Scenario 2: Unit Price Contract#

Setup:

  • Payment based on actual quantities

  • Original quantities are estimates

  • Final billing based on as-built

Process:

  1. Set up catalog with estimated quantities

  2. Bill actual quantities in estimates

  3. Final total may exceed or underbid original estimate

  4. Document variations with notes

Scenario 3: Lump Sum Items#

Setup:

  • Some work paid as lump sum, not unit price

Configuration:

Code: 001-MOBILIZATION
Description: Mobilization and general conditions
Unit: lot
Quantity: 1.00
Unit Price: $50,000.00
Total: $50,000.00

Billing: Bill 100% in first estimate or progressive percentage.

Reporting#

Catalog Reports#

Available reports:

  • Complete Catalog: All concepts with quantities and prices

  • Category Summary: Totals by category

  • Price List: Unit prices for reference

  • Quantity Tracking: Contract vs. billed quantities

Progress Reports#

Track project completion:

  • Percentage Complete: By quantity for each concept

  • Value Complete: Dollar value billed to date

  • Remaining Work: Unbilled quantities and values

Export Options#

  • PDF: Formatted catalog for printing/sharing

  • Excel: Editable spreadsheet for analysis

  • CSV: For import to estimating software

Troubleshooting#

Concept not appearing in estimate:

  • Verify concept is marked “Active”

  • Check concept belongs to correct contract

  • Confirm concept has quantity > 0

  • Ensure user has permission to view

Unit price won’t update:

  • Check if concept is linked to approved estimates

  • Review permission level (may require higher access)

  • Confirm change order approval if required

Total calculation incorrect:

  • Verify quantity and unit price values

  • Check for decimal place errors

  • Confirm proper unit of measurement

  • Review for manual overrides

Import failed:

  • Check Excel file format (must be .xlsx or .xls)

  • Verify column headers match expected names

  • Ensure no empty required fields

  • Review for special characters in text

Over-billing warnings:

  • Review estimate quantities vs. contract quantities

  • Check if change orders increased contract scope

  • Verify cumulative calculations are correct

  • Document justification if intentional

Integration with Estimating#

If you use external estimating software:

Export from Estimating Tool:

  1. Generate final estimate with quantities and prices

  2. Export to Excel format

  3. Import to Construbot as contract catalog

Sync Pricing:

  • Keep Construbot catalog as master

  • Export for estimating template

  • Import updated pricing after bid

See Also#