Expenses in Modules

In Darwin, expenses represent costs that are real, recurring, and necessary —
but are not materials or labor.

They capture the “everything else” that makes construction possible: permits, stipends, logistics, mobilization, inspections, and similar items.

Modeling expenses correctly is essential for realistic estimates.

What Are Expenses?

Expenses are non-material, non-labor costs that are associated with a module or scope of work.

Common examples include:

Permits and fees
Mobilization and demobilization
Stipends and allowances
Temporary facilities
Transportation and logistics
Site access or inspection fees
Environmental or regulatory charges

These costs often depend on context, not quantities alone.

Why Expenses Belong Inside Modules

Expenses are rarely isolated line items.

They usually belong to a specific scope of work: a foundation module, a structural package, an MEP assembly, etc.

By placing expenses inside modules:

Costs stay tied to their technical scope
Reuse becomes consistent across projects
Estimations remain complete and realistic
Adjustments propagate automatically

Modules become full representations of how work is actually delivered.

Types of Expenses in Darwin

Darwin supports multiple ways to model expenses, depending on how the cost behaves.

1. Fixed Amount Expenses

These are flat costs that apply once per module or project.

Examples:

Permit fee
Inspection fee
One-time mobilization cost

Example:

Building permit → $2,500
Site inspection → $800

Use fixed expenses when the cost does not scale with quantity.

2. Percentage-Based Expenses

These expenses scale relative to the cost of materials, labor, or the entire module.

Examples:

General overhead
Insurance
Contingency
Administrative fees

Example:

Overhead → 5% of module total
Insurance → 2% of labor cost

This is useful when the expense grows as the scope grows.

3. Distance-Affected Expenses

Some expenses depend on project location or distance.

Examples:

Transportation of crews
Per diem or stipends
Equipment hauling
Remote site logistics

In Darwin, these expenses can be configured to vary based on:

Project distance
Location category (urban / rural / remote)
Custom distance logic

This allows the same module to behave differently depending on where the project is executed.

Typical Expense Examples in Real Projects

Here are common patterns estimators model using expenses:

Crew stipend → fixed daily amount, affected by distance
Mobilization → fixed amount per project
Permits → fixed per module or per project
Logistics surcharge → percentage-based
Remote site allowance → distance-adjusted

These costs are often forgotten in early estimates — Darwin ensures they’re consistently included.

How Expenses Behave Across Projects

Once defined inside a module:

Expenses are reused automatically
Percentage logic remains consistent
Distance rules apply per project
Adjustments update all related estimates

This is where Darwin reduces risk:
expenses stop being “remembered manually” and start being systematically applied.

Best Practices

Keep expenses inside modules, not as ad-hoc line items
Use fixed amounts for permits and one-time fees
Use percentages for overhead-type costs
Use distance logic for logistics and stipends
Review expenses carefully in your first project (B1)
Benefit from reuse and consistency in future projects (B2+)

Expenses and Reusability

Expenses are part of why the second project is faster.

Once you’ve modeled:

permits
stipends
logistics
overhead

You don’t rebuild them — you reuse them.

This dramatically improves speed and consistency while reducing omissions.

Summary

Expenses allow modules to represent real-world construction costs, not just quantities.

They account for:

Context
Location
Scale
Operational reality

By modeling expenses correctly, Darwin becomes a true cost intelligence system — not just a quantity calculator.

Next Steps

Review expenses in your first project modules
Adjust them until they reflect reality
Reuse them in your next project
Observe how consistency and speed improve

Expenses are not an afterthought — they are part of the system.