How Brokers Can Help Investors Stress-Test a Construction Budget

Rising material prices, labor shortages, permitting delays, and scope changes can quickly send a construction project over budget. In August 2026, U.S. construction spending was down 1.7% from a year earlier. A cooling market doesn’t mean lower building costs though, and investors can still get stuck holding the bag when budgets run out during construction.

As a mortgage broker, you can help investors stress-test their construction budget ahead of closing, uncovering red flags and mitigating financing risks before they threaten the deal.

Key Takeaways

• Stress testing means modeling what happens to a budget when costs, timelines, or financing terms change.
• The project timeline and cost are linked. Delays add carrying costs and can stress reserves.
• Verify contractor estimates, labor and material costs, and all other expenses before submitting a loan request.
• Include adequate contingency reserves to prevent overruns in the construction budget before project completion.
• Brokers with a documented stress tests can create stronger submissions and gain repeat business from clients.

Why Construction Cost Estimation Needs a Stress Test

A construction budget can vary due to a number of factors including unexpected costs, scheduling, financing, and changing property values. Sometimes, if one variable changes, the others may also be affected. For example, a construction delay could increase interest expenses and delay sale or rental income for the property.

To keep construction budgets on track, you must confirm the project is still financially feasible when circumstances change. Otherwise, investors could find themselves short on funding once construction is already underway.

How to Calculate Construction Project Costs

Before testing different scenarios, confirm that the initial budget includes all the project’s expected costs.

• Hard costs: materials, labor, subcontractors, equipment, site work, mechanical systems, and finishes
• Soft costs: architectural and engineering fees, permits, legal, insurance, taxes, financing costs, and interest during construction

Hard costs typically are 70% of a budget and soft costs are 30%. Many of these soft costs are easy to miss and they tend to get left out of early estimates.

Four Areas to Include in a Construction Budget Risk Assessment

1. Material Prices and Labor Costs

Test what happens if material prices or labor costs exceed estimates. For example, model a 10 % increase in the remaining construction costs. Does the borrower have adequate contingency funds available to cover the difference?

2. Construction Delays and Financing Costs

Simulate a 60- to 90-day delay and calculate the additional interest, insurance, taxes, and other carrying costs. Check that the borrower’s reserves are sufficient to cover these costs with a longer holding period and whether the loan will need an extension if it takes longer to complete.

3. Project Scope and Completion Costs

Consider whether changes to the design, materials, or project size could increase costs. If the budget becomes too tight, evaluate whether simplifying the scope could help the investor finish sooner without undermining the property's marketability.

4. Exit Strategy and Permanent Financing

Test the project's viability if the resale price drops by 5%, the leasing process takes longer than anticipated, or rental income is lower than projected. Recalculate projected debt service coverage ratio (DSCR) and loan-to-value ratio (LTV) for a deal using more conservative assumptions for income and value.

Construction Budget Contingency Planning

A contingency reserve provides projects with a cushion to handle unexpected expenses without immediately demanding additional funding. A good starting point is 5% to 10% of the overall budget, but the right amount depends on the complexity of the project, the initial estimate, and the overall investment risk.

How to Prepare a Stronger Loan Submission

A detailed stress test allows lenders to understand the project’s expected costs and the borrower’s capacity to deal with setbacks.

Before submitting the loan request, prepare:

• An itemized budget supported by contractor estimates.
• A construction timeline and milestone-based draw schedule.
• A documented contingency reserve.
• Evidence of available borrower funds and committed capital.
• A summary of downside scenarios and proposed responses.
• Updated projections reflecting realistic costs and financing expenses.

These details help the lender evaluate the request and catch any issues earlier so you can better set the borrower’s expectations.

Partner With RCN Capital for Construction Financing

A construction budget includes stress testing gives lenders a better understanding of project risks and helps speed up the process of obtaining financing. If you want to ensure a smooth experience for your clients partner with a lender that has a proven track record in the real estate investing space. RCN Capital provides ground-up construction financing for real estate investors and lending partners. Visit our broker resources page to learn how partnering with RCN Capital can help you grow your lending business.