When you are buying a house make sure to have that inspected by a professional building inspector for some buyers this is the best investment since most of the defects are not visible and they may cost a lot of money to repair, the followings are the list of services that you should expect form a home inspector:

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What Is Inspected:
Roof - covering, drainage, flashing, skylight, chimney
Exterior - grading, eaves, wall covering, trim, doors, decks, driveway
Air Conditioning - type, size, energy source, age
Attic - roof structure, insulation level, signs of water leakage
Interior - walls, ceiling, floors, railings, windows, all components…
Fireplaces - type, vents, chimney
Structural - foundation, framing
Insulation - level, vapour barrier
Ventilation - roof, soffits, bathroom
Plumbing - water source, distribution system, sump pumps, water heating, drainage, related piping
Electrical - panel, amperage, main disconnect, grounding, ground fault systems
Heating - system type, energy source, age, vent system