New Construction vs Resale Home Inspection:
Key Differences Buyers Should Know
Both types of home need a professional inspection. But what the inspector looks for, and when they look, is different for a new build than it is for a 30-year-old house.
Two buyers are each closing on a home in the Portland area. One is buying a 1995 Colonial in Lake Oswego. The other is buying a brand-new home in a Hillsboro subdivision. Both need a home inspection. But what the inspector is looking for in each house, and when those inspections happen, is different in important ways.
Understanding the difference helps you ask better questions, schedule at the right time, and know what you’re getting in the report.
What the Inspector Is Actually Looking For
On a resale home, the inspection is largely about time. What has the home experienced? What’s been maintained, what’s been deferred, and what’s failed? Systems that were installed 20 or 30 years ago may be at or past the end of their service life. An aging roof, a furnace from 2003, galvanized plumbing that’s narrowing with mineral deposits: these are the concerns on a resale.
On a new construction home, the inspection is largely about workmanship. Was everything installed correctly? Are there gaps in the insulation? Are duct connections sealed? Was the flashing done right? New systems don’t fail from age, but they can fail from being put in wrong.
Both types of defect are worth finding. They just show up differently on the report.
Timing: The Biggest Practical Difference
For a resale home, the inspection happens once, during the inspection contingency period after your offer is accepted. You schedule it, the inspector walks the property, you get the report, and you proceed.
For a new construction home, timing matters more.
The first inspection is a pre-delivery inspection right before closing: the same kind of full inspection you’d get on a resale home, covering all finished surfaces, installed systems, roof, exterior, and foundation. Schedule it with enough time before closing for the builder to address findings.
The second is an 11-month warranty inspection, done before the builder’s one-year workmanship warranty expires.
Common Findings: New Construction
New builds don’t have deferred maintenance problems. What they have are construction defects, some cosmetic, some more significant.
Insulation gaps and compression are common. Installers work fast and sometimes skip difficult corners or compress batts to fit around obstructions. Neither type of error is obvious from looking at a finished wall. Thermal imaging can help show both.
HVAC duct connections get rushed. Flex duct joints that aren’t properly seated and sealed are a frequent finding on new construction. Conditioned air goes into the attic or crawlspace instead of the room. The system runs harder. Your utility bills run higher.
Grading and drainage get overlooked when final landscaping is still in progress. The lot should drain away from the foundation at a slope of at least 6 inches over the first 10 feet. Builder sites often don’t hit that mark.
Electrical polarity, proper grounding, and complete panel labeling are details that can be missed on a fast-moving construction site. Minor to fix. Important to document.
Flashing at roof penetrations, chimney chases, and wall-to-roof transitions is one of the more consequential categories. Improper flashing doesn’t cause immediate visible damage. It causes water intrusion over time. Catching it before closing, while the builder can still address it, is the whole point.
Real Inspection Photos
New Construction Defects, From Real Reports
Real photos from Russ's new construction reports of items this section covers.
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Gaps in duct mastic at a furnace closet connection. Leaky joints can waste conditioned air and pull in dust. -
Construction debris left inside a new electrical panel. It should be cleaned out by a qualified contractor. -
An undersized kickout flashing at a roof-to-wall joint. Heavy runoff can get past it and behind the siding.
Common Findings: Resale Homes
Resale inspections in the Portland area have their own common patterns, shaped by the region’s housing stock and climate.
Roofs take the brunt of Pacific Northwest weather. Missing or worn shingles, failed flashing, moss growth, and worn pipe boot seals are regular findings, not always failures, but conditions worth documenting.
Electrical systems in older homes are an area where Portland has some specific concerns. Federal Pacific Stab-Lok panels, which were installed widely from the 1950s through the 1980s and have documented breaker performance concerns, still show up in the Portland market. Knob-and-tube wiring appears in homes from the early 20th century. Aluminum branch circuit wiring shows up in homes from the late 1960s and 1970s. All of them warrant documentation and often warrant specialist evaluation.
Plumbing in Portland’s older housing stock includes galvanized steel pipe, which corrodes from the inside and restricts flow over time. Original clay sewer lines are common in homes built before the 1970s, and a sewer scope is recommended on every home.
Crawlspaces in the Pacific Northwest accumulate moisture. Vapor barrier condition, ventilation, and signs of past or current water intrusion are standard crawlspace items on any resale inspection in this region.
Underground heating oil tanks are another Portland-specific concern. Homes built before about 1970 and heated with oil heat may have had tanks decommissioned in place. Tank decommissioning and abandonment practices varied. Some were filled with sand. Some were partially filled. Some were just left.
Portland-area specific resale inspection concerns
- Federal Pacific and Zinsco panels still present in significant numbers in Portland’s 1950s-1980s housing stock
- Clay tile sewer lines common in homes pre-1970; sewer scope (arranged separately through a plumber) strongly recommended
- Underground oil tank decommissioning records available through DEQ, worth checking on older homes
- Knob-and-tube wiring in homes from pre-1940s, particularly in older Portland neighborhoods like SE and NE Portland
- Galvanized plumbing in homes from pre-1960s, often showing reduced flow by 50+ years of age
What Both Types Have in Common
Despite the differences, new and resale inspections share the same core structure. Every major system and accessible area gets examined. The inspector documents what they find with photos and, where applicable, video. The report describes conditions, explains what they mean technically, and flags anything that warrants specialist evaluation.
The inspector’s role is the same regardless of home age: document and report. Not advise on negotiations. Not say whether to walk away. Not recommend what to ask for in repairs. That’s the buyer’s call, with help from their agent.
Both types of inspection benefit from the buyer being present. Joining the inspector for the walkthrough near the end gives buyers context that a report can’t fully convey. Questions get answered. Conditions get shown, not just described. Buyers who attend learn more and feel more confident about the home they’re purchasing.
Whether you’re buying new or resale, the inspection serves the same purpose: give you clear, documented information about the home’s visible condition before you close. The specific concerns are different, but the reason for getting it done is exactly the same.
Getting Started
For a new construction home, confirm the completion date with your builder and schedule the inspection with time to spare before closing. For a resale, schedule during your inspection contingency period, early in the window, not the last day.
Trusted Home Inspections serves the full Portland metro and SW Washington. Russ Motyko is Oregon City’s only Certified Master Inspector®, dual-licensed in Oregon and Washington, and a licensed general contractor, with 3,000+ inspections completed.
Book at the online scheduler. For new construction details, see the new construction inspection page. For resale purchases, see the buyer’s home inspection page.
New Construction vs Resale Inspection FAQ
