Published: February 25, 2026 | Closer Look Home Inspectors · InterNACHI Certified · Mankato, MN

New Construction Inspection: What to Check at Each Building Phase

By Closer Look Home Inspectors | Updated February 2026 | (507) 721-3820

Buying a newly built home in the Mankato area is exciting, but the assumption that new means perfect is one of the most expensive misconceptions in real estate. Municipal building inspectors verify code compliance at specific checkpoints, but they do not evaluate overall quality, and their brief visits cannot catch every issue. An independent home inspection at strategic phases of construction protects your investment and catches problems when they are easiest and least expensive to correct.

Why New Homes Need Independent Inspection

In our experience inspecting new construction throughout Blue Earth County and southern Minnesota, we find an average of 50 to 100 deficiencies in newly built homes. These range from minor cosmetic issues to significant structural, mechanical, and safety concerns. Common problems include:

• Improperly installed flashing that will cause future water intrusion
• HVAC duct connections that are disconnected or leaking conditioned air into unconditioned spaces
• Grading that directs water toward the foundation rather than away
• Missing or improperly installed insulation creating thermal bypass
• Plumbing connections that are not fully secured
• Electrical violations missed during municipal inspection

Phase 1: Pre-Pour Foundation Inspection

Before concrete is poured, verify that footings are at proper depth (42 inches minimum in our climate zone for frost protection), formwork is properly aligned and braced, reinforcing steel is correctly placed, and radon mitigation piping is installed per the radon-resistant new construction specifications common in Blue Earth County's Zone 1 area. This is the most time-sensitive inspection phase.

Phase 2: Pre-Drywall (Frame) Inspection

This is the most valuable inspection phase for new construction. Once drywall covers the framing, most deficiencies become invisible and extremely expensive to correct. The pre-drywall inspection evaluates:

• Framing quality: Proper sizing, spacing, and connection of structural members. Notching and boring of joists and studs within allowable limits.
• Window and door installation: Proper flashing, sealing, and attachment. Improperly flashed windows are the number one source of water intrusion in new construction.
• Electrical rough-in: Proper wire sizing, box fill, GFCI and AFCI circuit planning, and required outlet locations.
• Plumbing rough-in: Proper pipe sizing, slope on drain lines, venting configuration, and securing of supply lines.
• HVAC ductwork: Proper sizing, connection integrity, insulation on ducts in unconditioned spaces, and return air paths.
• Insulation installation: Proper fit in wall cavities without compression, gaps, or voids. Vapor barrier placement.
• Air sealing: Sealing around penetrations, rim joists, and transitions between conditioned and unconditioned spaces.

Phase 3: Final Inspection

The final inspection after construction is complete but before closing evaluates the finished product:

• All mechanical systems operated and performance verified
• Exterior grading and drainage patterns
• Roof covering, flashing, and gutter installation quality
• Finish quality of interior surfaces
• All safety features including smoke detectors, CO detectors, and GFCI/AFCI protection
• Radon testing to verify the passive mitigation system is effective
• Exterior caulking and weatherproofing completeness

Our thermal imaging during the final inspection can reveal insulation gaps and air leaks before they cause comfort or energy problems.

Phase 4: 11th Month Warranty Inspection

Most builders provide a one-year warranty on workmanship. Scheduling a professional inspection before this warranty expires gives you the opportunity to identify and claim warranty-covered defects. See our detailed 11th month warranty inspection guide for more information.

Common Builder Responses and Your Rights

Some builders resist independent inspections, but as the buyer, you have the right to have any property inspected before purchase. A reputable builder welcomes independent inspection as an opportunity to demonstrate quality. If a builder discourages inspection, consider it a red flag about their confidence in their work quality.

When deficiencies are identified, document them in writing and request correction before closing. Your purchase agreement and inspection report provide the documentation needed to hold builders accountable.

Building or buying new construction in Mankato? Call Closer Look Home Inspectors at (507) 721-3820 to schedule phase inspections.