A general home inspection is the single most useful thing most buyers ever pay for in a transaction. In 2–4 hours, a licensed inspector walks the roof, attic, structure, electrical, plumbing, HVAC, and every interior room, then hands you a written report of defects — usually for $300–$500. This guide walks you through exactly what they check, room by room, so you know how to read the report and what to do about it.

What a general home inspection is (and isn't)

A general home inspection is a visual, non-invasive examination of a home's major systems and components. The inspector looks, tests, opens panels and hatches, runs fixtures, and documents what they see — but they do not cut open walls, move heavy furniture, dig, or run laboratory tests. You get a written report, typically 20–60 pages with photos, usually delivered within 24 hours.

The inspection covers the home's condition on that day, not a guarantee of the future. In most states the buyer orders it during the due-diligence period, and findings are used to negotiate repairs, credits, or, in serious cases, to walk away.

Typically excluded from a standard general inspection: sewer line scoping, mold testing, radon testing, termite/WDO inspection, well and septic evaluation, chimney inspection, pool equipment deep-testing, and asbestos/lead testing. Many inspectors offer these as add-ons ($75–$250 each). Read your contract — the inclusions list is where the real scope lives.

Roof and exterior

The inspector evaluates the roof covering (shingles, tile, metal, membrane), flashing, gutters, downspouts, soffits, fascia, and penetrations like vents and skylights — from the roof itself or a ladder at the eaves. They look for missing, cracked, or curling shingles; lifted or deteriorated flashing; nail pops; ponding on flat roofs; and signs of patching or layered-over older roofs.

  • Remaining life: a typical asphalt shingle roof lasts roughly 15–30 years. If the roof is at year 20 of a 25-year shingle, plan for replacement ($8,000–$20,000+ on a typical single-family home).
  • Installation quality: improper nailing, missing drip edge, and skipped step-flashing at walls are among the most common defects.
  • Active leaks or stains: exterior findings pair with the attic section — stains on roof decking seen from below confirm what the outside suggests.

Exterior checks include siding and trim condition, window and door seals, grading and drainage (ground should slope away from the foundation, roughly 6 inches of fall in the first 10 feet), driveways and walkways for trip hazards, deck and porch structure, and clearance of vegetation and mulch against siding.

Attic, insulation, and ventilation

The inspector enters the attic (access permitting) and checks the underside of the roof decking for stains, mold-like growth, and daylight at penetrations — the classic tell of an active leak. They verify insulation type and depth. Common benchmarks: blown cellulose or fiberglass should sit around 10–14 inches for R-38 in most U.S. climate zones; anything under 6–8 inches is thin by modern standards and costs you in cooling and heating bills.

Ventilation matters as much as insulation. They check that soffit vents aren't blocked by insulation (baffles should be present), that ridge, gable, or powered vents exist and are functional, and that bathroom and kitchen exhaust fans vent to the outside — not into the attic, which is a top-five defect in resale homes and a moisture/mold engine. Kitchen range hoods venting into the attic or soffit are likewise flagged.

Structure and foundation

Foundations are checked from outside and, where accessible, from the crawlspace or basement. The inspector documents the foundation type (slab, crawlspace, basement), notes visible cracks with their location and width, and watches for the patterns that matter: horizontal cracks in block walls, stair-step cracks in mortar joints, and cracks wider than about 1/4 inch generally warrant a follow-up with a structural engineer. Hairline vertical cracks in poured concrete are common and usually cosmetic — the report should distinguish.

In crawlspaces they check floor joists and beams for sagging, notching, or rot; vapor barrier presence; standing water or efflorescence; and pest evidence. Basement checks include sump pump presence and function, moisture staining, and whether the water heater and mechanicals show corrosion from past water events.

Electrical: panel, grounding, GFCI and AFCI protection

The inspector opens the main electrical panel and documents the service size (100, 150, or 200 amps — 200 is the modern standard), breaker vs. fuse, and wiring types. Common flagged defects: double-tapped breakers, oversized breakers on undersized wire, missing knockouts, and aluminum branch-circuit wiring in older homes (a known fire-risk pattern needing evaluation).

They test a representative number of receptacles: proper grounding, reversed polarity, and open grounds are routine findings. GFCI protection is checked where required — kitchens, bathrooms, garages, exteriors, and near laundry/utility sinks. AFCI protection is expected on bedroom circuits in homes built under modern codes. A house wired before these requirements isn't automatically "defective," but missing modern protection is noted as a safety improvement.

Plumbing: water heater, supply, drains, and fixtures

Water heaters get a close look: age (typical tank life is 8–12 years), capacity, temperature setting (120°F is the standard safe recommendation), TPR valve and proper discharge piping, expansion tank, and corrosion at connections. A 14-year-old tank isn't broken, but budget $1,200–$2,500 for replacement.

The inspector runs every fixture — faucets, showers, toilets, tubs — checking pressure, hot/cold function, drainage, toilet stability, and visible leaks under sinks. They identify the supply pipe material (copper, PEX, CPVC, galvanized, or polybutylene — the last being a red flag for insurers) and the main shutoff location, which you should learn during the inspection.

HVAC: heating and cooling equipment

The inspector records each system's type, fuel, age, and capacity, then operates it in each mode the weather allows — they won't run AC below about 60°F outdoor temperature or heat above about 80°F, to avoid damaging equipment. They measure temperature differential across the coil (a healthy cooling system typically drops supply air 14–22°F below return air), check the condensate drain, filter condition, refrigerant line insulation, and outdoor unit clearance.

Typical HVAC life: 12–20 years for most residential systems. A 17-year-old condenser that runs fine today is still a near-term replacement ($5,000–$12,000+ for a full system), and the report's age data is what lets you plan rather than get surprised.

Interior rooms, kitchen, bathrooms, and garage

Every accessible room gets checked: windows (do they open, latch, and stay up; fogged double-pane glass indicating failed seals), doors (latch, alignment, hardware), floors, walls and ceilings (stains suggesting leaks above, cracks), and a representative sample of outlets and switches. Stairways are checked for handrail presence and baluster spacing (the 4-inch sphere rule is the common safety benchmark).

Kitchens: the inspector runs the range burners and oven, checks the range hood (and where it vents), dishwasher (runs a cycle, checks for leaks), disposal, and microwave. Bathrooms add exhaust fan function and termination, shower/tub surround integrity, and signs of slow leaks around toilet bases.

Garages: the vehicle door gets an operational and safety-reverse test, the fire separation between garage and living space is checked (self-closing fire-rated door, sealed penetrations), and any garage-located water heater or furnace is checked for proper elevation and combustion air.

What this guide does not cover — and when to hire a specialist

A general inspection is a mile wide and an inch deep by design. Hire a specialist when the report flags something beyond visual assessment: a structural engineer for significant foundation movement (typically $300–$600 for an evaluation letter), a licensed electrician for panel or wiring hazards, a roofer for a roof at end of life, a plumber with a camera for the sewer line ($150–$300 for a scope — cheap insurance on any home older than about 25 years), and a licensed WDO inspector for termite evidence. Mold-like growth found in the attic or crawlspace warrants a mold assessor, not a guess. None of this means the house is bad — it means you're doing diligence the way it's meant to be done: generalist first, specialists for the red flags.

Frequently asked questions

Should I attend the inspection?

Yes — strongly. The report is useful, but watching the inspector work teaches you where the shutoffs are, how the panel is labeled, and which findings actually matter versus which are maintenance notes. Plan to be there for the last hour at minimum; most inspectors walk you through the highlights at the end. Sellers generally leave the property during the inspection.

How long does an inspection take, and what does it cost?

A typical single-family home takes 2–4 hours; larger or older homes run longer. Expect $300–$500 for the general inspection in most markets, with add-ons (radon, sewer scope, WDO, mold) priced separately. Prices run higher in high-cost metro areas and for homes over roughly 2,500 square feet.

What happens if the inspection finds major problems?

During your due-diligence or inspection contingency period, you can typically negotiate repairs or a credit, accept the home as-is, or cancel the contract. Get contractor estimates for anything significant before negotiating — a report line that says "roof nearing end of life" becomes actionable when you attach a $12,000 roofer quote.

Can the inspector tell me whether to buy the house?

No, and a good one won't. Inspectors report conditions; the buy/don't-buy decision is yours. What they will do is help you rank findings by safety, cost, and urgency — ask them directly which three items they'd address first if it were their house.

Is a new home exempt from needing an inspection?

No. New construction has its own defect patterns — incomplete flashing, unsealed penetrations, HVAC and plumbing rough-in errors — and municipal code inspections check minimum standards, not quality. A private inspection in phases (pre-drywall, final, and warranty) is standard practice for new builds.