Inside a Home Inspection: Every Phase, Start to Finish
A home inspection is a few hours of one person walking your prospective house with a flashlight, a ladder, and a tablet, turning things on and off and writing down what looks wrong. Nothing is opened up, nothing is guaranteed, and no number gets attached to the property’s value. What you get is a plain-language picture of the house’s current condition so you can decide whether to buy, renegotiate, or walk. Here is how the day actually unfolds and what each stage is for.
Who the inspector answers to, and what that means for scope
General home inspectors work to a written standard of practice, and that standard is the reason two inspectors describe the same house in roughly the same terms. The two dominant ones are the InterNACHI Residential Standards of Practice and the ASHI Standard of Practice. Both define the inspection as visual and non-invasive, and both list the same core systems: roof, exterior, structure, foundation, basement or crawl space, heating, cooling, plumbing, electrical, interior, insulation and ventilation, and built-in appliances. Anything outside that list, like a swimming pool, a septic tank, or a well, is either a separate add-on or a specialty pro’s job.
The practical takeaway: the inspector is checking whether systems are present, functioning, and safe on the day of the visit. They are not predicting how long your furnace will last or certifying that the wiring meets the latest code edition.
Before the day: booking, contract, and access
Most buyers schedule the inspection inside the inspection contingency window in their contract, usually three to seven days after mutual acceptance. You sign an inspection agreement that spells out scope and limits, and you pay a fee that on the Colorado Front Range typically lands between $400 and $550 for a standard single-family home, more for larger or pre-1950 properties. Detailed pricing sits in the pre-purchase inspection cost breakdown.
The single thing that ruins an inspection is utilities being off. If the gas, water, or power is shut down, the inspector cannot fire the furnace, run the water heater, or test outlets, and those items get marked “not evaluated” instead of inspected. Confirm with the listing agent that everything is on and that the attic hatch, electrical panel, and crawl-space opening are reachable.
The exterior pass
Inspectors usually start outside and often start alone, before the buyer arrives, because the exterior is a slow, methodical read that a conversation interrupts. They walk the grading and drainage first, looking for ground that slopes toward the foundation rather than away from it, then work through walkways, driveways, decks and railings, siding, trim, windows and doors from outside, and the visible foundation.
The roof gets attention proportional to how they can reach it. Inspectors walk a roof when it is safe and low-slope enough, and otherwise inspect from a ladder at the eave or from the ground with binoculars. On the Front Range this pass routinely turns up hail bruising on shingles and dented soft-metal vents and gutters, which is why so many Colorado transactions end with a roofer’s second opinion.
The interior and systems walkthrough
Inside, good inspectors follow a fixed route, commonly top to bottom, so no room gets skipped. Room by room they operate a representative sample of outlets, switches, and windows, run water at every fixture, flush toilets, check under sinks for leaks, and scan ceilings and walls for the stains and cracks that hint at water or movement. Sampling is deliberate: testing every one of a hundred outlets would blow past the time budget, so they check enough to catch a pattern and note anything abnormal.
Then come the systems that make or break a deal:
- Heating and cooling run through a full cycle. The inspector reads the temperature split across the unit and looks at the age plate, flame or coil condition, and filter.
- Electrical means opening the service panel, photographing the inside, and checking for hazards like double-tapped breakers, aluminum branch wiring, or missing GFCI protection near water.
- Plumbing covers the water heater, visible supply and drain lines, water pressure, and functional flow and drainage.
- Attic and crawl space are where hidden defects live: insulation gaps, blocked ventilation, active leaks, and amateur framing or wiring changes by past owners.
Total on-site time for a typical 1,500-to-3,000-square-foot house is two to four hours; older and larger homes run longer. The inspection duration guide breaks down what stretches the clock.
Add-ons that get collected during the visit
Several common services piggyback on the general inspection but produce results on their own timeline:
- Radon test ($125–$250): a continuous monitor or a pair of charcoal canisters sits in the lowest livable level for 48 hours or more. This matters in Colorado because the state sits in EPA Radon Zone 1, and the EPA action level is 4.0 pCi/L. Our radon testing hub covers placement and mitigation.
- Sewer scope ($175–$300): a camera runs the main line to find root intrusion or a collapsed section, worth it on homes with original clay or cast-iron lines.
- Mold air sampling ($150–$400): spore-trap cassettes go to a lab, ordered when there is visible growth, a musty smell, or a recent water event.
- Wood-destroying organism (WDO) ($75–$150) and, on pre-1978 homes, lead-paint screening per EPA lead guidance.
Sample collection happens on-site, but lab analysis for radon, mold, and WDO arrives separately, so your main report often lands before those numbers do.
The closing walkthrough and the report
The last 30 to 60 minutes is the buyer’s most valuable window. The inspector walks you to the actual problem areas, shows you the condition, and explains how serious it is and roughly what direction the fix runs. If you can only attend part of the day, attend this part. Take notes, ask which findings are safety issues versus maintenance, and ask what a given repair typically costs.
The written report usually arrives 24 to 48 hours later. Expect an executive summary of the significant items, system-by-system observations, photographs of each defect, and severity labels, commonly along the lines of safety hazard, major defect, minor defect, and informational note. Length is a weak quality signal; a 40-page report with a clear photo and a specific recommendation for each finding beats a 100-page document padded with boilerplate. See a real one in the sample inspection report.
What a home inspection does not do
Because it is visual and non-destructive, a standard inspection excludes opening walls or removing fixtures, surveying boundaries, calculating square footage, assigning property value, certifying code compliance, and testing for radon, mold, asbestos, or lead unless you add those services. When a condition needs a specialist, the inspector’s job is to flag it and recommend follow-up, not to diagnose it. That referral is a feature, not a dodge, and it is one of the core benefits of getting the inspection before you commit.
Frequently asked questions
Do I have to be there?
No, but attend the final walkthrough if nothing else. Seeing a defect in person and hearing the inspector explain it is far more useful than reading about it later. Some inspectors prefer you arrive only for that summary so the earlier documentation goes faster.
What if the utilities are off?
Anything that needs power, gas, or water gets marked “not evaluated” rather than inspected. That leaves a hole in your due diligence, so confirm utilities are on before the visit or arrange a return trip, which usually costs extra.
Does a clean report mean the house is problem-free?
It means nothing significant was visible on inspection day. Concealed defects behind finished walls, intermittent electrical faults, and seasonal issues can escape a one-day visual review, which is exactly why the standard is worded around what is observable.
How do I know the inspector is qualified?
Check certification with InterNACHI or ASHI, read a sample report, and confirm any state licensing that applies. The hiring an inspector overview walks through credential verification.
Thresholds cited here reflect current EPA guidance and the InterNACHI and ASHI standards of practice; verify the licensing rules that apply in your state.