Building Code Due Diligence for Property Buyers (2026)

Buying or refinancing a commercial property without a thorough review of its building code history is one of the most common and costly oversights in commercial real estate. Permit gaps, zoning violations, and undisclosed compliance issues can quietly erode a property's value, delay closings, and expose buyers and lenders to liabilities they never anticipated.

This guide covers the full scope of building code due diligence for commercial property acquisitions, from permit verification and zoning analysis to life safety reviews and accessibility compliance.

Whether you are a lender evaluating collateral risk or a development team preparing for a major acquisition, understanding exactly what to look for in a building's regulatory history is essential. Burnham Nationwide provides code consulting and due diligence services that help buyers and lenders identify compliance risks before they become financial problems.

Key Takeaways: Building Code Due Diligence

• Building code due diligence uncovers permit gaps, zoning violations, and safety risks before a commercial property transaction closes.
• Lenders increasingly require building code compliance verification as a standard part of loan underwriting for commercial acquisitions.
• Unpermitted work can reduce appraised values, delay financing, and create post-closing legal exposure for new owners.
• Burnham Nationwide conducts municipal records evaluations, code assessments, and life safety surveys to reduce acquisition risk.
• Starting code due diligence early in the transaction timeline gives buyers leverage to negotiate pricing or walk away.

What Is Building Code Due Diligence?

Building code due diligence is the process of investigating a commercial property's compliance with applicable building codes, zoning ordinances, and permit requirements before an acquisition or refinancing closes. It goes beyond the standard property condition assessment by examining the regulatory history of the building itself.

This process typically includes a review of municipal permit records, certificates of occupancy, zoning classifications, and any outstanding code violations. The goal is to identify conditions that could affect the property's legal use, insured value, or financing eligibility.

For buyers, this investigation reveals whether past construction work was properly permitted and inspected. For lenders, it confirms that the collateral backing a loan is legally compliant and free of regulatory encumbrances that could reduce its value.

Why Does Code Compliance Matter in Property Acquisitions?

Code compliance issues affect three areas simultaneously during a commercial transaction: the property's appraised value, its insurability, and its financing eligibility. A single unresolved building code violation can trigger cascading problems that delay or derail a deal entirely.

Appraisers may exclude square footage added without permits from the gross building area, directly lowering the property's valuation. According to ASTM International's E2018 standard for property condition assessments, identifying material physical deficiencies, including code compliance issues, is a core objective of the baseline assessment process.

Insurance carriers may deny or limit coverage for areas of the building where work was completed without inspection. If a fire or structural failure occurs in an unpermitted section, the claim may be rejected, leaving the owner fully exposed.

How Do Permit Gaps Create Risk for Buyers and Lenders?

A permit gap exists when visible construction work on a property has no corresponding permit record in the local building department's files. This means the work was never inspected by a code official and may not meet the safety standards required by the applicable building code.

For buyers, inheriting unpermitted work means inheriting the obligation to resolve it. Municipalities can require the current owner to obtain retroactive permits, which often carry penalty fees of two to five times the original permit cost. If the unpermitted work does not meet current code, the owner also bears the expense of bringing it into compliance, or in severe cases, demolishing it.

For lenders, permit gaps create collateral risk. A property with significant unpermitted work may be worth less than the loan amount if the municipality orders removal or if insurance coverage is denied after a loss event. Thorough permit management review during due diligence helps quantify this exposure.

What Should a Building Code Due Diligence Review Include?

A comprehensive building code due diligence review examines several distinct areas of compliance. Each area carries its own risks and requires specific expertise to evaluate properly.

Municipal Permit Records Review

Start by pulling the complete permit history for the property from the local building department. Most municipalities maintain searchable databases organized by address or parcel number. Look for permits covering all visible construction, renovation, and tenant improvement work. Compare the permit records against the building's current condition to identify gaps.

Pay close attention to "open" permits, meaning work that was started but never received a final inspection sign-off. Open permits transfer to the new owner at closing and can trigger fines or block future permit applications until resolved.

Zoning and Land Use Verification

Verify that the property's current use aligns with its zoning classification. A building zoned for office use that is being operated as a retail space, or a property with a nonconforming use that has lapsed, can create significant legal and financial exposure.

Request a zoning confirmation letter from the local planning authority documenting the property's permitted uses, setback requirements, and any variances or special permits on file. Cross-reference this information against the property's actual operations.

Certificate of Occupancy Review

The certificate of occupancy (CO) confirms that a building was inspected and found compliant with applicable codes at the time of issuance. Check whether the CO reflects the building's current use and occupancy classification. A CO issued for one use does not automatically cover a different one.

If renovations or changes in use have occurred since the last CO was issued, additional permits and a new CO may be required. Failing to obtain an updated CO before closing can create problems for tenants, insurers, and future buyers.

Life Safety and Fire Code Compliance

Life safety systems, including fire alarm systems, sprinklers, egress paths, and emergency lighting, are among the most scrutinized elements in any building code review. Deficiencies in these areas can trigger immediate corrective action requirements from the local authority having jurisdiction.

A life safety survey should evaluate the condition and code compliance of all fire protection and egress systems against the current edition of the applicable fire code and the International Building Code (IBC). Burnham Nationwide's code consulting team conducts these reviews starting from the schematic design phase through construction document finalization.

Accessibility and ADA Compliance

The Americans with Disabilities Act (ADA) sets federal accessibility requirements that apply to commercial properties. Each state may impose additional requirements beyond the federal baseline. Non-compliance with ADA standards can result in lawsuits, fines, and mandatory remediation.

During due diligence, assess whether the building's entrances, common areas, restrooms, and parking meet current accessibility standards. For older buildings, focus on whether required modifications are "readily achievable" under the ADA's existing-facility provisions.

How Does Building Code Due Diligence Differ from a Standard Property Inspection?

A standard property condition assessment (PCA) focuses on the physical condition of building systems: the roof, HVAC, plumbing, electrical, and structural components. It identifies deferred maintenance and estimates remaining useful life. A code due diligence review, by contrast, examines whether the building's construction, modifications, and current use comply with applicable regulations.

The two assessments overlap in some areas but serve different purposes. A PCA may identify a roof that needs replacement in five years. A code due diligence review would identify whether the roof was installed under a valid permit, meets the current energy code, and complies with the local fire rating requirements.

Both assessments are important for lenders and buyers. Combining them provides the most complete picture of a property's physical and regulatory condition.

What Are the Most Common Code Violations Found During Acquisition Due Diligence?

Certain code violations appear frequently during commercial property due diligence reviews. Recognizing these patterns can help buyers and lenders focus their investigation on the highest-risk areas.

Unpermitted Tenant Improvements

Commercial buildings with a history of multiple tenants often have interior modifications completed without permits. Partition walls, plumbing additions, electrical upgrades, and HVAC modifications for individual tenant spaces may have been done without building department approval.

Occupancy Classification Mismatches

When a building's actual use does not match its permitted occupancy classification, the entire structure may be considered non-compliant. This is common in adaptive reuse projects where industrial or warehouse space has been converted to office, retail, or residential use without the necessary code upgrades.

Expired or Lapsed Certificates of Occupancy

In some jurisdictions, certificates of occupancy must be renewed periodically or reissued when tenants change. A lapsed CO can affect the building's legal status and complicate financing and insurance.

Fire and Life Safety Deficiencies

Outdated sprinkler systems, non-compliant fire alarm panels, blocked egress paths, and missing fire-rated separations are among the most common life safety findings. These deficiencies carry the highest urgency because they directly affect occupant safety and can trigger enforcement actions.

How Lenders Use Code Due Diligence in Underwriting

Lenders have a direct financial interest in the code compliance status of properties they finance. A building with unresolved code violations or significant unpermitted work represents a higher risk to the lender's collateral position.

During underwriting, lenders typically require a property condition assessment that includes a review of code compliance, environmental conditions, and ADA accessibility. Some lenders go further by requiring a standalone code compliance report that evaluates the building against current building codes and identifies material deficiencies.

Findings from the code due diligence review can affect loan terms in several ways. Lenders may require remediation escrows, reduced loan-to-value ratios, or additional reserves for deferred compliance work. In severe cases, unresolved code violations may result in the lender declining to finance the property.

Step-by-Step Process for Conducting Building Code Due Diligence

A structured approach to code due diligence ensures nothing is overlooked. The following steps outline a practical process for buyers and their consultants.

Step 1: Request and Review Municipal Records

Contact the local building department and request the complete permit history, violation history, and certificate of occupancy records for the property. Use the Assessor's Parcel Number (APN) for the most accurate results. Many jurisdictions now offer online permit portals, though older records may require an in-person request.

Step 2: Conduct a Physical Site Survey

Walk the property and document all visible construction, alterations, and building systems. Compare what you see on-site against the permit records and floor plans on file with the building department. Note any discrepancies, including additions, enclosures, or system upgrades that do not have corresponding permits.

Step 3: Verify Zoning and Land Use Compliance

Confirm the property's zoning designation and permitted uses with the local planning and zoning department. Verify that the building's current use, density, setbacks, parking, and signage conform to the zoning ordinance. Identify any variances, conditional use permits, or planned development agreements that apply.

Step 4: Evaluate Life Safety and Fire Code Compliance

Engage a qualified code consultant to evaluate the building's fire protection systems, egress paths, fire-rated assemblies, and emergency systems against the applicable codes. This evaluation should reference both the code edition under which the building was originally permitted and any applicable retroactive requirements.

Step 5: Assess ADA and Accessibility Compliance

Review the building's accessibility features against current ADA Standards for Accessible Design and any applicable state or local accessibility codes. Focus on entrances, routes of travel, restrooms, parking, and common areas. Document deficiencies and estimate remediation costs.

Step 6: Compile Findings Into a Due Diligence Report

Organize all findings into a comprehensive report that categorizes issues by severity and estimated remediation cost. Include recommendations for resolving each finding and timelines for compliance. This report becomes a negotiation tool during the transaction and a planning document for post-acquisition remediation.

When Should Building Code Due Diligence Begin?

The most effective time to start code due diligence is during the letter-of-intent (LOI) or pre-contract phase of the transaction, before the purchase agreement is fully executed. Starting early gives the buyer time to assess the scope of any compliance issues and negotiate price adjustments, credits, or seller obligations before becoming contractually bound.

Waiting until the formal due diligence period begins, which is often 30 to 60 days for commercial transactions, compresses the timeline for investigation and limits the buyer's negotiating leverage. Code reviews can take several weeks when municipal records are incomplete or require in-person retrieval, so early engagement helps avoid schedule pressure.

Burnham Nationwide's in-house research team provides comprehensive due diligence reports that detail all the steps required for permit and code compliance verification in each municipality.

How to Negotiate Based on Code Due Diligence Findings

Code due diligence findings give buyers quantifiable data to use during price negotiations. Each finding can be translated into an estimated remediation cost, which provides a factual basis for requesting a price reduction or seller credit.

For minor issues, such as expired permits or administrative violations, a seller credit at closing may be sufficient. For more significant findings, including unpermitted structural work, life safety deficiencies, or zoning non-conformities, the buyer may need to request a larger price adjustment or require the seller to complete remediation before closing.

In some cases, findings may justify walking away from the deal entirely. If the unpermitted work cannot be legalized under current zoning, or if remediation costs exceed the property's value premium, the risk may outweigh the investment opportunity.

What Role Does Environmental Review Play in Code Due Diligence?

Environmental compliance and building code compliance are closely connected, though they are typically evaluated through separate assessment processes. A Phase I Environmental Site Assessment (ESA) examines the property for potential contamination from past uses, while the code review examines the building's regulatory compliance history.

Certain environmental findings directly affect code compliance. Properties with asbestos-containing materials, lead paint, or underground storage tanks may require remediation before construction permits can be issued for renovation work. Environmental conditions can also affect the building's insurability and the lender's willingness to finance the acquisition.

Coordinating the environmental and code due diligence reviews ensures that findings from one assessment inform the other, providing a more complete risk picture for the buyer and lender.

In Conclusion: How to Protect Your Investment Through Code Due Diligence

Building code due diligence is not optional for commercial property buyers and lenders who want to make informed acquisition decisions. Permit gaps, zoning violations, life safety deficiencies, and accessibility shortfalls all carry real financial consequences that affect property value, financing terms, and post-closing obligations.

The most effective approach is to start early, engage qualified professionals, and treat the code review as a core component of the transaction, not an afterthought. A thorough code due diligence review provides the data you need to negotiate confidently, structure appropriate protections, and proceed with a clear understanding of the property's regulatory condition.

Burnham Nationwide's code consulting and due diligence services integrate municipal records research, on-site surveys, and expert code analysis into a single, comprehensive review. With over 30 years of experience and a nationwide team of licensed professionals, Burnham helps buyers and lenders identify compliance risks before they close.

FAQs About Building Code Due Diligence

What is building code due diligence in commercial real estate?

Building code due diligence is the process of verifying a commercial property's compliance with building codes, zoning ordinances, and permit requirements before a purchase or refinancing. It identifies regulatory risks that affect value, insurability, and financing eligibility.

Who is responsible for unpermitted work after a property changes hands?

The current owner becomes responsible for resolving unpermitted work after closing, regardless of who originally performed the construction. Municipalities enforce code violations against the property, not the individual who did the work.

How does Burnham Nationwide conduct code due diligence reviews?

Burnham Nationwide conducts municipal records evaluations, fire and life safety surveys, accessibility reviews, and code and zoning assessments. The team compiles findings into a comprehensive report that identifies compliance issues and recommends remediation steps.

Can building code violations prevent a property sale from closing?

Significant code violations can delay or block a sale by reducing the appraised value, triggering lender requirements for remediation escrows, or causing insurance carriers to deny coverage. Identifying these issues early through due diligence helps keep transactions on track.

What is the difference between a property condition assessment and a code compliance review?

A property condition assessment evaluates the physical condition of building systems and estimates remaining useful life. A code compliance review examines whether construction, modifications, and current use comply with applicable building codes and regulations. Both are recommended for commercial acquisitions.

When should I start building code due diligence for a commercial property purchase?

Start during the letter-of-intent or pre-contract phase, before the purchase agreement is signed. Early engagement gives you time to assess compliance risks, negotiate pricing adjustments, and avoid schedule pressure during the formal due diligence period. Burnham Nationwide's research team can begin pulling municipal records and jurisdictional requirements at this stage.