You’ve probably seen the lists. “Top 10 home inspection red flags!” Foundation cracks, old wiring, water stains — fine, sure, those matter. But here’s what most of those lists won’t tell you: whether a crack is a problem or just a house settling the way houses do. Whether that water stain is active or from a leak somebody fixed three owners ago. Whether the panel needs $200 of work or $4,000.
That’s the gap I’m trying to close with this post. I’ve spent over 20 years building, renovating, and repairing homes before I ever started inspecting them, and I still run an active contracting business today. When I walk a house, I’m not just trained to spot these issues — I’ve fixed most of them with my own hands. That changes what I can tell you about what you’re actually looking at.
While this list doesn’t pretend to tackle every question, there are some that come up a lot or are misunderstood that I’d like to address here.
So let’s go through the real ones — what they are, why they matter, and what I’m actually thinking when I find them.
Foundation and Structural Movement
This is the one that scares people most, and for good reason — it can be expensive and it’s not always obvious. But not all movement is equal.
Hairline cracks in a poured concrete foundation, especially vertical ones under a quarter-inch wide, are usually just normal curing and settling. I see them constantly and they’re rarely worth losing sleep over. What changes the conversation is horizontal cracking, stair-step cracks in block foundations, bowing walls, or doors and windows that have started sticking because the frame around them has shifted.
What I’m looking for beyond the crack itself: is there a pattern? Is it active (fresh, sharp edges) or old (weathered, painted over)? Is the wall itself out of plumb? Is there water staining nearby that explains it? A foundation that’s been slowly pushed by hydrostatic pressure from poor drainage tells a different story than one with a single isolated settlement crack from 1970.
Given how many of these homes I’ve actually repaired, I can usually tell you whether you’re looking at a five-hundred-dollar parging job or something that needs an engineer. That distinction is the whole ballgame for a buyer trying to decide what to do next.
Roof Condition and Age
The roof is one of the most expensive single-system replacements in a house, and it’s also one of the easiest things for a buyer to overlook because it’s, well, up there.
Curling or missing shingles, granule loss, soft spots underfoot, and flashing that’s pulled away from chimneys or valleys are the obvious flags. Less obvious: a roofline that looks wavy from the street, which can point to sheathing problems underneath, or daylight visible in the attic where there shouldn’t be any.
Age matters as much as condition. A 20-year-old asphalt roof that looks fine today might still have three good years left — or it might not, depending on how it was installed and ventilated. I look at attic ventilation and insulation alongside the roof itself, because poor venting cooks a roof from underneath and shortens its life regardless of how new the shingles look.
Electrical Systems
New Hampshire and Vermont have a lot of older houses, and that means I run into knob-and-tube wiring, aluminum branch wiring, and outdated fuse panels more than inspectors in newer markets do. None of these automatically mean “walk away,” but they all mean “budget for it.”
Knob-and-tube isn’t inherently dangerous if it’s intact and hasn’t been buried under insulation, but most insurers won’t write a policy on a house that still has it, which makes it a practical problem even if it’s not a safety one in the moment. Aluminum wiring from the 60s and 70s is a different story — it’s a known fire risk at the connections unless it’s been properly pigtailed with copper. And a fuse panel, or a double-tapped breaker, or an overcrowded panel without enough capacity for what a modern household actually draws, tells me the electrical system hasn’t kept pace with the house around it.
Another very common finding around NH & VT is an original panel that’s undersized, which has one or more sub panels downstream of it, to accommodate all the additional breakers that have been added over the years. One of the problems here is that the service wasn’t upgraded to provide more capacity, they are just forcing more load on the old infrastructure. It isn’t uncommon for me to cite issues with these configurations, and generally the recommendation is for a service upgrade with a new panel properly sized and configured. There’s only so many times you can kick the can down the road before someone has to take responsibility and fix what should have been fixed in the first place!
There are a ton of quirks with fixing or replacing electrical infrastructure in an old house. Sure, any inspector can tell you “this should be replaced”. I can generally at least tell you what the scope of that might look like. Is the house post and beam? Are the walls plaster on lath? Is there nicer trim, built ins, woodwork that should be preserved? Can the baseboards be strategically removed to accommodate new wiring, or would they probably get wrecked in the process? Are the framing members run on the flat in the partition wall so that they can’t accommodate standard depth electrical boxes? Is an insulation or window upgrade something that you are considering or may think about in the near future?
All these questions and their respective answers directly influence the recommendations I may give you for repair sequencing, the scope of the work, and the contractors and coordination that would be required to do the job. That’s where I bring real value from my background of running jobs just like what you need to have done. I understand it from the inside out.
Water Intrusion and Moisture
Water is the patient destroyer. It doesn’t announce itself with a bang — it just sits there, quietly costing you money for years before anyone notices.
Basement and crawlspace moisture, efflorescence on foundation walls, musty odors, and staining around windows or in the attic are the signs I’m checking for room by room. Just as important is what’s happening outside: grading that slopes toward the house instead of away from it, gutters that dump water right at the foundation, downspouts with no extensions. Half the “wet basement” problems I find aren’t basement problems at all — they’re drainage problems that happen to show up in the basement.
This matters more here than in a lot of places, because our frost-heave cycles and spring thaw push a lot of water around that a flatter, drier climate doesn’t have to deal with. I’ve regraded yards and fixed drainage on enough of these properties to know which fixes actually solve the problem and which ones just move the water somewhere else for a season.
Any inspector can flag “negative grading, recommend further evaluation by a qualified professional”. Okay, that may be true, your grading might slope back to the house, and that’s not a good situation and would be a great candidate for correction. However, you may be in a city lot with the neighbor’s property beginning four feet away from the walls of your house. How much grading can you do there? Or let’s say you are out in the country, and your house is built smack up against a giant hill, and it’s on ledge. Your options are going to be limited.
I’ve dealt with every one of these problems in a myriad of ways, and have had to learn what creative solutions exist, and how they might be implemented. I’m not going to offer to do any of the work, I have a policy of not working on any house that I’ve inspected for at least twelve months following the inspection. But I can advise you on what solutions might look like, and what kind of contractor you need to communicate with to move forward.
Aging Plumbing
Galvanized steel pipe and polybutylene are the two I flag most. Galvanized pipe corrodes from the inside out over decades, which means a house can have decent water pressure right up until it doesn’t — the pipe just keeps narrowing internally until it fails. Polybutylene, common in homes built from the late 70s through the mid-90s, has a track record of failing at fittings and is something most plumbers will tell you to plan around even if it’s not leaking today.
In rural NH and VT, where almost everyone is on a private well, water is not created equal. The varying hardness, PH, and mineral profiles each produce different interactions with our plumbing. Even modern pex plumbing can be vulnerable to accelerated wear in the fittings. Copper pipe, long an industry standard and still a solid choice, can oxidize surprisingly fast.
Early identification of accelerated wear on plumbing, and remediation of the underlying conditions, can save a lot of money in the long run.
Waste and drainage plumbing involve a whole other risk profile. Getting water out of your house is as important as getting the water supplied to the fixtures where you enjoy using it. Early identification of potential failure points can save a lot of pain later.
I also look at water heater age and condition, signs of past leaks under sinks and around the water heater pan, and whether the supply lines and shutoffs are something a homeowner could actually work with in an emergency. None of this is glamorous, but it’s the kind of thing that turns into a 2 a.m. phone call to a plumber if it’s ignored.
What’s Actually NOT a Red Flag
This list wouldn’t be complete without the other half — because I watch buyers panic over things that genuinely don’t deserve it just as often as I watch them shrug off things that do.
A long inspection report is not a red flag. My job is to document everything I find, down to a loose cabinet hinge, because that’s the standard I hold myself to. A report with forty items on it from a house in good shape looks scarier than a report with eight items from a house with real problems — but the second house is the one you should worry about. Read the report for severity, not length.
Cosmetic wear — worn carpet, dated finishes, a few nail pops in drywall, a door that needs adjusting — is just a house that’s been lived in. It’s not a system failure and it’s not a negotiating point worth burning goodwill over.
In older houses, context is required for every finding. If you enjoy the charm and history of older houses, you must embrace a lot of the unique characteristics that come with them. An old house is a totally different thing than a newer one, it’s sometimes like they are different species, and I adapt my inspection process and findings to accommodate their differences.
Minor settling cracks, especially in newer homes during their first few years as materials cure and adjust, are normal. So is some condensation on basement walls in summer humidity. The goal isn’t a zero-defect house — there’s no such thing — it’s understanding which defects are maintenance items and which ones are financial decisions.
The Bottom Line
A home inspection isn’t about finding reasons to be afraid of a house. It’s about knowing exactly what you’re buying, what it’ll cost you, and when. The value of having someone who’s actually built and repaired these systems — not just studied them — is being able to tell you which findings are routine and which ones deserve real attention, instead of leaving you to guess.
That’s the lens I bring to every inspection across New Hampshire and Vermont, and it’s exactly why I built my Home Inspection services around that background in the first place. If you’ve got a report in hand and you’re not sure what you’re looking at, or you’re getting ready to put an offer in and want to know what to expect, I’m happy to talk it through before you book anything.
— Austin Reida, Owner of Resonant Homes, NH/VT Licensed Home Inspector
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Frequently Asked Questions
What is the single biggest red flag in a home inspection?
Active structural movement — things like horizontal foundation cracks, bowing walls, or stair-step cracking in block foundations — tends to top the list because it affects everything else built on top of it and can be the most expensive to fix. That said, the size of the red flag depends entirely on context: a hairline crack from normal settling isn’t the same problem as active movement, which is exactly why an experienced eye matters more than a checklist.
Are foundation cracks always a deal breaker?
No. Most homes have some cracking, and hairline vertical cracks under about a quarter-inch are usually just normal curing and settlement. What matters is whether the cracking is active, horizontal, or paired with other signs like bowing, water staining, or sticking doors and windows nearby.
Is knob and tube wiring dangerous?
Intact knob-and-tube wiring that hasn’t been covered with insulation isn’t necessarily an immediate safety hazard, but most homeowners insurance companies won’t cover a house that still has it. That makes it a practical and financial issue even when it isn’t actively dangerous, and it’s usually worth budgeting to replace.
Should I be worried if my inspection report has dozens of items on it?
Not by itself. Inspectors are trained to document everything, including minor maintenance items, so a long report often just reflects thoroughness rather than a house in bad shape. Focus on the severity of each item — safety hazards, major systems, and expensive repairs — rather than the total count. I’ve written plenty of reports with 40+ items on them in a house that I would consider buying myself.
What’s the difference between a maintenance item and a real red flag?
A maintenance item is something a homeowner can reasonably handle over time as part of normal upkeep — caulking, a loose railing, a furnace filter overdue for a change. A real red flag involves safety, structural integrity, or a major system nearing failure, where the cost and urgency are high enough to affect your decision to buy or your negotiating position.
Why does a contractor background matter for spotting red flags?
Anyone can be trained to recognize the visual signs of a problem. Knowing whether that problem is a minor fix or a major one, roughly what it costs to correct, and what exactly that correction entails — comes from having actually repaired these systems, not just studied them. That’s the difference between a generic warning and a real answer.