How Should Investors Assess a Development Project's Construction Budget and Timeline?

A development budget is credible when each major cost and date traces to a defined scope, a responsible party, and current supporting evidence. I would first focus on what remains uncertain: incomplete design, unpriced work, approvals, and the gap between construction completion and income starting.

Trace Costs to the Project Scope

Request the drawings and specifications, quantity takeoffs, line item budget, bid tabulation, and contractor proposals. Reconcile them line by line. Mark each amount as a fixed price, allowance, or estimate, and ask what is excluded. Pay particular attention to site preparation, utility work, permits, insurance, professional fees, financing costs, and owner supplied items. Confirm the same scope appears in the budget and contracts, along with the project sources and uses.

Ask who prepared the estimate and who reviewed it independently. For major or unusual work, have a construction consultant or quantity surveyor compare quantities and pricing with the plans. Check bid dates, expiration terms, escalation clauses, and whether the contractor obtained pricing from the relevant trades. A low bid can conceal incomplete scope or optimistic allowances. Ask, "Which work is not covered by a signed price?" and "What assumptions could change the cost after work begins?"

Test the Schedule as a Chain of Dependencies

Request a detailed schedule that identifies design completion, permit submissions and approvals, procurement, mobilization, construction phases, inspections, commissioning, and occupancy approval. Ask the contractor to identify the critical path and long lead items. Compare promised dates with approval status and supplier commitments. A calendar date in a presentation is not the same as a schedule supported by commitments.

Check which tasks can proceed at the same time and which must wait for another task. Ask, "What must happen before this milestone can be met?" and "Which delay would push the completion date, even if other work stays on schedule?" Review weather allowances and inspection time. Also account for commissioning and time to prepare space for tenants. After construction, test the separate lease up period and the time needed to reach the income level assumed in the financing plan.

Model Overruns and the Cash They Require

Test construction costs above budget at several levels, such as 10%, 20%, and 30%, and test construction inflation at 15% and 25% for development work. Show which costs drive each case. Do not count contingency twice or treat amounts already committed to known scope gaps as available reserves. In each case, calculate remaining contingency, added equity needed, extra interest and carrying costs, and the resulting completion date.

Then extend construction and lease up by 50% from the projected duration, and test rental rates 25% below plan. Ask whether a construction or bridge loan would mature before stabilization, what extension rights apply, and what conditions a lender may impose. Identify the exact reserve source if cash is needed. The capital call and liquidity planner can help map that timing against available liquidity.

Checklist

• Obtain plans, specifications, bids, and a line item budget.
• Mark every major cost as fixed, an allowance, or an estimate.
• Get an independent review of quantities and major pricing assumptions.
• Request a critical path schedule with approval and procurement status.
• Model cost increases, construction delays, and slower lease up.
• Confirm reserve sources, loan maturity terms, and extension conditions.

For contract and financing provisions with legal or tax effects, talk with your attorney or CPA.

Go deeper: partners and service providers step of the How to Start guide.

Read next: What should a family office check in a property's rent roll and lease agreements?

Sources: Family Office Club investor due diligence framework, How to Start a Family Office. Informational only, not financial, legal or tax advice.