Know the framing, insulation and airflow story above the ceiling.

• Sheathing: OSB/plywood roof deck that supports the roof covering
• Rafters / trusses: framing members that carry roof loads
• Baffles: keep soffit vents open so insulation doesn’t block airflow
• Insulation types: batt, blown or spray foam and what R-values mean
• Soffit & ridge vents: intake and exhaust that create attic ventilation

The skin and flashing that keep bulk water out of the structure.

• Roof coverings: shingles, metal, tile or membrane that shed water
• Underlayment: secondary water-shedding layer beneath the covering
• Flashing: metal at valleys, walls and penetrations to direct water
• Drip edge: metal at eaves/rakes that protects edges and feeds gutters
• Penetrations: vents, stacks and flues that must be properly flashed

Everything between weather and structure.

• WRB: housewrap or membrane behind siding
• Siding types: vinyl, fiber cement, stucco or wood and how they shed water
• Brick veneer: weep holes, air gap and ties that drain and support
• Deck structure: ledger, joists, posts and connectors that carry loads
• Grading & drainage: soil slope and downspout discharge away from the home

Understand what’s behind the drywall and how people move through the space.

• Wall framing: studs and headers that support loads and openings
• Floor system: joists and subfloor that span and support floors
• Ceiling framing: joists or truss chords supporting ceilings
• Window anatomy: jamb, sash, glazing and sill and how they operate
• Stair geometry: rise, run, headroom and handrail/guard basics

High-use area where plumbing, electrical and safety all meet.

• Anti-tip bracket: device preventing a range from tipping
• Dishwasher connections: supply, shutoff, drain and high loop or air gap
• Sink plumbing: basket strainer, tailpiece and P-trap
• GFCI/AFCI zones: required protection near counters and sinks
• Range hood: ducted or recirculating and backdraft damper purpose

Moisture control is everything here.

• Shower/tub waterproofing: pan, membrane and slope to drain
• Backer board: cement or foam board in wet areas
• Toilet assembly: flange, wax ring and shutoff valve
• Exhaust fan: ducted to exterior not attic
• Caulk vs grout: flexible joints vs rigid filler

Top leak and lint-risk location.

• Dryer venting: smooth metal duct, short runs and proper termination
• Washer standpipe: correct height, diameter and P-trap location
• Drain pan: protection under washers over finished spaces
• Water shutoffs: accessible hot and cold valves
• GFCI/AFCI: required safety protection in laundry areas

How furnaces or boilers create and move heat.

• Burner assembly: where gas or oil burns to create heat
• Heat exchanger: keeps flue gases and indoor air separated
• Blower & ducts: fan and ductwork moving warm air
• Venting system: B-vent, PVC or direct-vent piping
• Condensate system: drains or pump for high-efficiency units

Refrigerant loop between indoor coil and outdoor unit.

• Refrigerant lines: suction and liquid lines
• Compressor: outdoor unit that pressurizes refrigerant
• Evaporator coil: indoor coil absorbing heat
• Condensate drain: pan and drain line for moisture
• Reversing valve: switches heat pumps between heat and cool

From the utility service to the last receptacle.

• Service drop/mast/meter: how power arrives and is measured
• Main panel: breakers, bus bars and neutral/ground bars
• Breaker types: standard, GFCI, AFCI and dual-function
• Wiring types: NM cable, armored cable, copper and aluminum
• Bonding & grounding: safe path for fault current and lightning

Pressurized supply plus gravity drains.

• Supply piping: PEX, copper, CPVC or Poly-B carrying pressurized water
• Drain/waste piping: ABS, PVC or cast iron carrying used water
• P-traps vs S-traps: approved water seals vs obsolete traps
• Vents: stacks, branch vents and AAVs preventing siphoning
• Water heater components: tank, TPR valve, shutoff and expansion tank

Where structure meets soil.

• Foundation types: poured concrete, block, stone, slab or ICF
• Footings: widened concrete bases spreading loads into soil
• Damp-proofing/membranes: coatings or sheets on exterior walls
• Perimeter drains: weeping tile collecting groundwater
• Sump system: pit, pump and discharge moving water away

Managing fire, smoke and clearances.

• Fireplace types: masonry, prefab, gas insert or direct-vent units
• Flue liner: clay or metal lining protecting chimney walls
• Chimney crown & cap: top surface and cover shedding water
• Hearth & clearances: non-combustible zone and minimum distances
• Draft principles: how hot gases rise and exit without backdrafting