A standard inspection typically covers the roof and its visible condition, the exterior cladding, grading and drainage around the foundation, windows and doors, the structure where it is visible, the foundation and basement, the heating and cooling systems, the electrical panel and visible wiring, visible plumbing and water pressure, insulation and ventilation where accessible, and the interior finishes, floors, walls and ceilings.

Appliances, where included in the sale, are usually operated briefly rather than tested thoroughly. The inspector will typically run taps, flush toilets, turn on the furnace and the air conditioning if conditions allow, and open and close a sample of windows and doors.

Expect two to three hours for an average home, longer for a large or older one. If someone is offering to do it in forty-five minutes, that tells you what you are buying.

Anything behind a wall, under a floor or beneath the slab. Inspectors do not cut into finishes. Plumbing inside walls, wiring behind drywall and the condition of a buried drain line are all unknown.

Anything blocked by belongings. A basement full of boxes, a crawl space with no access hatch, a garage packed to the ceiling. The inspector notes it as inaccessible and moves on, which is one reason a cluttered house is a worse purchase than a clear one.

Specialist areas that need their own expert. Mould and air quality, asbestos in older materials, chimney interiors, septic systems, wells, swimming pools and spas, underground oil tanks, and detailed structural engineering. Some inspectors offer some of these as add-ons. Most are a separate professional.

Anything seasonal or weather dependent. Air conditioning cannot be tested safely in freezing weather, a roof under snow cannot be properly assessed, and a basement that leaks only in heavy spring rain will look dry in August.

The future. An inspector reports condition on the day. A furnace working perfectly on inspection day can fail in November. That is not a failure of the inspection.

What are your qualifications and professional association memberships?

Do you carry errors and omissions insurance, and liability insurance?

How long have you been inspecting, and what is your background?

How long will you be at the property, and may I attend?

When do I get the report, and may I see a sample one?

Will you take my call afterwards if I have questions?

A background in construction, engineering or the trades matters, and so does how clearly they explain things. An inspector who cannot make a problem understandable to you in person will not do it in writing either. A sample report tells you a great deal before you commit.

Reports are written defensively, which means everything is noted and the serious items can look similar to the trivial ones on paper. Standing next to someone who can point at a thing and say whether it matters is a different experience entirely.

The questions worth asking on site: which of these would you fix first, roughly what does that cost, is this normal for a house of this age, and is there anything here that would make you walk away.

That last question is the most valuable one in this article. Inspectors see hundreds of houses and they will usually answer it honestly.

Also ask them to show you where the shut-offs are: main water, gas, and the electrical panel. You will want to know on your first night in the house.

A forty page document full of flagged items is normal, including on a well-maintained house. Sort what you read into three groups.

Structural, safety and water. Foundation movement, active leaks, electrical hazards, anything involving the roof. These matter and they deserve a quote before you decide anything.

Aging systems. A furnace at twenty years, a roof near the end of its life. Not emergencies, but real money within a few years, and legitimate to factor into what you pay.

Maintenance items. Caulking, a loose railing, a cracked outlet cover. These fill most of the page count and almost none of the cost.

On what to do next: if the inspection was a condition of your offer, you generally have the option to proceed, renegotiate or walk, within the limits of what the clause allows. Reopening price over minor maintenance items rarely goes well and can cost goodwill you need later. Save it for the first group.

Where a property has an offer date, keeping an inspection condition often makes your offer uncompetitive. The alternative is to inspect beforehand, with the seller's permission, and then submit without the condition knowing what you are buying.

This is increasingly common and most sellers permit it, because an inspected buyer is a buyer less likely to collapse. Your agent arranges access, usually in the days before the offer date.

The cost is real: you pay for an inspection on a house you may not get, and if you bid on three houses you may pay three times. Weigh that against waiving the condition blind, which is the genuine alternative. One inspection fee is cheap compared with a structural problem you committed to without knowing.

Where a seller provides their own pre-listing inspection, read it, but remember it was commissioned by the other side. It is useful information, not a substitute for your own. Our guide to competing offers covers the wider decision about which conditions to keep.

Having your own inspection done before listing lets you fix the small things that would otherwise be used against you, removes surprises late in a deal, and gives buyers confidence, which supports firm offers.

The catch is that once you know about a material defect, you may have disclosure obligations, and you cannot simply discard a report you do not like. Discuss the implications with your lawyer and your agent before commissioning one, not after reading it.

On balance it is often worth doing, particularly on an older home where buyers will assume the worst anyway. Our guide to what adds value before selling covers which of the findings are worth acting on.