What Should a Home Inspector Actually Check?

I run All Seasons as an owner-operator out of Wyncote, and I've been performing home inspections across the Philadelphia region since 2003. One of the most common questions I get from first-time buyers — usually after they've already hired someone else — is some version of: "Should my inspector have checked that?" Most of the time, the answer is yes.

Not all inspections are equally thorough. Some inspectors evaluate every accessible system in the home. Others do a visual walkthrough and call it a day. The difference can be tens of thousands of dollars in unexpected repairs.

Here's a system-by-system guide to what a quality home inspection should cover, based on InterNACHI Standards of Practice and ASHI Standards of Practice and what I find in the field on Montgomery County, Philadelphia, and Delaware County homes every week.

What does a home inspector check on the roof and in the attic?

The roof is one of the most expensive components of any home. A replacement can run $10,000 to $30,000 depending on size, material, and complexity. A thorough inspection includes physically accessing the roof (when safe) and evaluating shingle condition, flashing around chimneys and vents, gutters and downspouts, soffit and fascia, and signs of wear or damage.

Inside the attic, the inspector should evaluate the roof structure from below (rafters, decking, trusses), insulation type and depth, ventilation (ridge vents, soffit vents, gable vents), and signs of moisture intrusion, pest activity, or prior repairs.

Red flag: An inspector who only looks at the roof from the ground or uses a drone as their default approach is giving you less information about one of the home's most critical systems.

What does a home inspector check on the foundation and structure?

The foundation is what everything else sits on. Cracks, settling, bowing walls, and moisture intrusion at the foundation level can indicate serious structural issues that are expensive to address.

A thorough inspection evaluates visible foundation walls (from the interior and exterior), signs of horizontal or stair-step cracking, evidence of past or current water intrusion, floor levelness, and the condition of structural components like beams, columns, and joists — particularly in basements and crawl spaces.

In the Philadelphia region, homes from different eras have different structural characteristics. A stone foundation from the 1920s presents different inspection considerations than a poured concrete foundation from the 1990s. An experienced inspector knows what to look for in each type.

What does a home inspector check in the electrical system?

Electrical defects are both a safety hazard and a potentially expensive repair. The inspection should include opening the main electrical panel to evaluate wiring type, breaker condition, proper grounding and bonding, and overall capacity.

Specific items to check include double-tapped breakers, aluminum branch wiring (common in 1965-1973 homes and a fire risk), Federal Pacific or Zinsco panels (known safety concerns), GFCI protection in wet areas (bathrooms, kitchen, garage, exterior), and a representative sample of outlets tested for proper wiring.

The inspector should also evaluate the service entrance, meter base condition, and whether the home's electrical capacity is adequate for its current use.

Red flag: An inspector who doesn't open the electrical panel — or who only tests a handful of outlets without opening the panel — is skipping one of the most important safety evaluations in the entire inspection.

What does a home inspector check in the plumbing system?

A thorough plumbing evaluation covers the supply system (what brings water in), the drain system (what takes water out), and the water heater.

The inspector should identify the supply pipe material (copper, PEX, galvanized steel, polybutylene — each has different implications), check water pressure, evaluate the water heater's age, condition, and safety features (TPR valve, proper venting, drain pan), run faucets and flush toilets to check for drainage speed and leaks, and look for signs of active or past leaks under sinks, at fixtures, and at visible pipe connections.

In older Philadelphia-area homes, galvanized steel supply lines are a common finding. These corrode from the inside over time, restricting water flow and eventually requiring replacement. An experienced inspector can assess the remaining useful life of galvanized pipes based on visible condition and water pressure at fixtures.

What does a home inspector check on HVAC heating and cooling systems?

The HVAC system is another high-cost item — a furnace replacement runs $3,000 to $7,000, and a central air system $4,000 to $10,000. The inspection should evaluate the age and condition of the furnace (or boiler), the central air system, ductwork (where visible), thermostat operation, and air filtration.

The inspector should operate the heating and cooling systems, check for proper airflow at registers, evaluate the heat exchanger for visible cracks (a carbon monoxide risk), and assess the overall condition and remaining useful life of major components.

Red flag: An inspector who says the HVAC system is "fine" or "in good condition" without specifying the age, type, and observed condition of each component is giving you a superficial assessment. HVAC components have defined service lives, and knowing where yours falls on that timeline is critical for budgeting.

What does a home inspector check in the basement and crawl space?

Basements and crawl spaces are where many of the most serious — and most commonly missed — issues hide. Moisture intrusion, foundation cracks, structural concerns, pest damage, and mold growth are all frequently discovered in below-grade spaces.

A thorough inspector will enter the crawl space (when accessible and safe) and evaluate the foundation from below, check floor joists and structural supports, look for moisture, standing water, or evidence of past flooding, evaluate vapor barriers, insulation, and ventilation, and check for pest damage or activity.

In the basement, the inspector should look for efflorescence (white mineral deposits indicating moisture migration through concrete), cracks in walls or the floor slab, signs of water staining or past flooding, and the condition of the sump pump system if present.

Red flag: An inspector who doesn't enter the crawl space — or who only looks through the access opening without going inside — is potentially missing the most critical findings in the home.

What does a home inspector check on the exterior of a home?

The exterior evaluation covers the building envelope — everything that keeps weather out and conditioned air in. This includes siding condition (wood, vinyl, brick, stucco, fiber cement), window and door condition and weatherstripping, grading and drainage around the foundation, walkways, driveways, and patios, decks, porches, and railings, and exterior electrical outlets and lighting.

Grading is particularly important. If the ground slopes toward the foundation rather than away from it, water will collect at the foundation wall. This is one of the most common causes of basement moisture problems and one of the easiest to identify during an inspection.

What does a home inspector check on the interior of a home?

Inside the home, the inspector evaluates walls, ceilings, and floors for signs of structural movement (cracks, unevenness, sagging), windows for operation, sealing, and condition, doors for proper operation (which can indicate structural settling), staircases and railings for safety, and bathrooms for proper ventilation, caulking, and moisture management.

The inspector is not evaluating cosmetic condition — paint colors, wallpaper, or carpet stains are not part of a home inspection. The focus is on the functional condition of the home's systems and components.

What does a home inspector check for insulation and ventilation?

Proper insulation and ventilation affect energy efficiency, comfort, and moisture management. The inspector should evaluate the type and depth of attic insulation, whether the attic has adequate ventilation (to prevent moisture buildup and ice damming), bathroom and kitchen exhaust ventilation, and dryer vent routing and condition.

Inadequate attic ventilation is one of the most common findings in Philadelphia-area homes, particularly in older construction. It contributes to ice dams in winter, excessive heat in summer, and moisture-related deterioration of roof decking and structural components year-round.

What does a standard home inspection NOT cover?

It's important to understand the boundaries. A standard home inspection does not include areas that are not safely accessible (inside walls, underground), mold air sampling or lab analysis (this is a separate service), radon testing (also a separate service), sewer line scope or well testing, pest or termite inspection (typically performed by a separate specialist), swimming pools or detached outbuildings (unless specifically requested), and code compliance evaluation.

Many of these additional services can be added to your inspection. In the Philadelphia region, the most commonly added services are mold/air quality testing, radon testing, and sewer scope inspections. Your inspector should be able to advise you on which additional services are appropriate for the specific home you're purchasing.

What should you expect from a thorough home inspection in the Philadelphia area?

A thorough home inspection is a hands-on, system-by-system evaluation that takes two to four hours for a typical single-family home. If your inspector is finishing faster than that, or if you notice that major systems aren't being physically accessed, ask questions. You're paying for a comprehensive evaluation, and you deserve one. A standard home inspection covers 400+ checkpoints across all major systems — that's not a number you can hit in 60 minutes. The average detailed inspection report runs 40–60 pages with photographs, so if you receive a 10-page checklist, you're not getting the full picture. One specific thing to flag on older homes: electrical panels under 100 amps are considered undersized for modern home use and are flagged in nearly every pre-1970 home inspection I perform in this region.

At All Seasons, Bob personally oversees every inspection and follows InterNACHI and ASHI standards of practice. Every accessible system is evaluated, every finding is explained during the walkthrough, and a detailed digital report with photos is delivered within 24 hours. Call 610-348-6728 for a free estimate.

A standard home inspection report from All Seasons runs 50 to 70 pages and includes photographs of every significant finding.