1) Active Water Intrusion (Roof, Attic, Interior)

Why it’s a red flag: Water is the #1 home killer in BC. Persistent moisture drives rot, mold, insulation failure, and electrical hazards.

BC climate & code notes: Coastal storm systems, wind-driven rain, and complex rooflines challenge flashings and attic ventilation. Current BC practice expects effective roof drainage, eave protection/ice-dam strategies in snow zones, and continuous air/vapour control.

Warning signs: Freshly painted ceilings, musty odours, cupped flooring, stained sheathing, wet insulation, rusty fasteners, elevated moisture meter readings.

Maintenance timeline: Roof visual check each spring/fall and after major storms; clean gutters 2–4×/year near trees; replace roof at end of service life (asphalt 15–25 yrs; metal 40+; torch-on 20–25, depending on product and exposure).

When to call a pro: If you see active dripping, soft roof decking, or moisture in concealed spaces; if bathroom fans aren’t ducted outdoors; if attic frost/condensation is present.

Real-life BC scenario: North Shore home with complex valleys leaks at underlapped step flashing after atmospheric river event.

Homeowner action checklist:

• Inspect attic for dark stains, wet insulation, or visible daylight at penetrations.

• Verify bath/kitchen fans exhaust outside, not into attic.

• Clear gutters/downspouts; confirm downspouts discharge away from foundation.

• Photograph stains and monitor after rain to confirm activity.

• Schedule roofer for flashing/penetration review.

2) Poor Drainage & Damp Foundations (Perimeter Drains/Crawlspaces)

Why it’s a red flag: Saturated soils and failed perimeter drains lead to hydrostatic pressure, foundation cracks, moldy crawlspaces, and slab heave.

BC climate & code notes: Many older homes (pre‑rainscreen era) rely on original clay/concrete tile drains; tree roots and silt often clog them. Crawlspaces in coastal BC need ground vapour barriers and ventilation or conditioning.

Warning signs: Efflorescence (white salts) on foundation walls, standing water in crawlspace, high humidity/rust, musty odour, peeling parging, sloped or soggy landscaping toward the house.

Maintenance timeline: Gutter/downspout cleaning 2–4×/year; landscape grading review annually; camera-inspect perimeter drains every 5–10 years or if symptoms appear.

When to call a pro: Recurrent water entry, bowing walls, or if you suspect failed drains/ sump issues—call drainage contractor; structural cracking—call engineer.

Real-life BC scenario: Richmond bungalow with high water table shows tide-influenced seepage at slab edges; perimeter drain flush and sump upgrade resolve it.

Homeowner action checklist:

• Ensure final grading slopes away from foundation (aim ~5% for first 2 m where feasible).

• Extend downspouts well clear of the footing.

• Lay 6‑mil poly ground cover in crawlspace; seal seams; consider conditioned crawlspace in damp zones.

• Book perimeter drain camera/flush if the age is unknown or symptoms are present.

3) Roofing at End-of-Life or Poor Installation

Why it’s a red flag: Worn shingles or bad detailing allow hidden rot at sheathing and fascia.

BC climate & code notes: Wind-uplift on Gulf Islands/Strait of Georgia, heavy wet snow inland, and moss growth in rainforests shorten roof life. Ice-dam protection and balanced attic ventilation are key in snow zones (Sea‑to‑Sky, Interior).

Warning signs: Granule loss, exposed mat, brittle or curling shingles, moss clumps, missing or short step flashing, inadequate kickout flashing, ponding on low-slope roofs, sagging ridges.

Maintenance timeline: Moss treatment as needed (soft wash; avoid pressure); replace damaged flashings immediately; reroof at end of service life.

When to call a pro: If more than one roof layer exists, decking feels soft, or any signs of widespread failure.

Real-life BC scenario: Nanaimo home without kickout flashing behind stucco chimney shows interior wall staining.

Homeowner action checklist:

• Check all penetrations (vents, chimneys, skylights) for intact flashing and sealant.

• Add kickout flashing where roof meets wall.

• Plan replacement if >70% of life is gone or leaks are recurring.

4) Structural Movement, Rot, or Seismic Vulnerabilities

Why it’s a red flag: Structural problems threaten safety and insurability.

BC climate & code notes: High seismicity along the coast and Vancouver Island; moisture-driven rot at sills and decks; heavy snow loads in Interior/Whistler require robust framing and bracing.

Warning signs: Wide stair-step or horizontal cracks, sloping floors, bouncy framing, rotted sill plates, undersupported decks, unreinforced masonry chimneys, missing hold-downs or sill anchorage.

Maintenance timeline: Annual deck/structure walk-through; tighten hold-downs; replace decayed members promptly.

When to call a pro: Any notable differential settlement, chimney cracking, or deck ledger concerns—call structural engineer.

Real-life BC scenario: 1970s Vancouver home with unbraced cripple walls and loose sill bolts flagged for seismic retrofit.

Homeowner action checklist:

• Probe suspect wood for softness; repair rot before it spreads.

• Verify deck ledger is flashed and mechanically fastened; check guard/handrail integrity.

• Strap water heaters and brace cripple walls where required.

• Consult engineer for URM chimneys or sagging roofs in snow zones.

5) Unsafe Electrical Systems

Why it’s a red flag: Shock and fire hazards, insurance complications.

BC climate & code notes: Many 1960s–70s homes have aluminum branch circuits; older homes may have knob‑and‑tube; GFCI/AFCI protection is expected in modern installations; damp coastal environments demand corrosion-resistant devices outdoors.

Warning signs: Warm breakers, multiple double‑taps, undersized service conductors, overloaded circuits, open junction boxes, mixed copper/aluminum terminations without proper connectors, missing GFCI/AFCI where required, water entry at mast.

Maintenance timeline: Test GFCIs monthly; replace exterior covers/gaskets as needed; panel review every 5–10 years by a licensed electrician.

When to call a pro: Any DIY wiring, aluminum branch circuits, recurring breaker trips, or signs of overheating.

Real-life BC scenario: Tri‑Cities rancher with aluminum wiring and copper pigtails done with improper connectors—remediated by electrician.

Homeowner action checklist:

• Install/verify GFCI in kitchens, baths, exterior, garages; AFCI on bedroom/living circuits as applicable.

• Label circuits; avoid overfusing.

• Replace damaged cords/receptacles; add in‑use covers outdoors.

• Get an Electrical Contractor to evaluate aluminum or knob‑and‑tube systems.

6) Problem Plumbing & Sewer Issues

Why it’s a red flag: Leaks and water damage; costly sewer repairs.

BC climate & code notes: Watch for Poly‑B (polybutylene) (1980s–90s) and Kitec (PEX‑AL‑PEX) (1995–2007) with dezincification‑prone brass fittings; galvanized steel supply pipes restrict flow; many older neighbourhoods use clay tile sewers vulnerable to root intrusion.

Warning signs: Stains on ceilings below baths, slow drains, orange crust on brass fittings, blue/green stains (aggressive water), water pressure >80 psi, sump pump constantly running.

Maintenance timeline: Replace supply hoses to laundry and fixtures every 5–7 years; water heater lifespan typically 8–12 years (tank), longer for on‑demand; sewer line camera at purchase and if backups occur.

When to call a pro: Presence of Poly‑B/Kitec/galvanized; repeated backups or sewer smells; high static pressure—install PRV.

Real-life BC scenario: East Van character home with clay tile lateral blocked by mature maple roots; spot repair and cleanout installation solved backups.

Homeowner action checklist:

• Identify supply piping types; plan repipe if Poly‑B/Kitec/galvanized present.

• Install/verify pressure‑reducing valve (PRV); aim ~50–60 psi.

• Insulate exposed pipes in unheated spaces.

• Schedule sewer camera inspection, especially with big street trees or pre‑1970s homes.

7) Insulation & Ventilation Deficiencies (Condensation/Ice Dams)

Why it’s a red flag: Heat loss, mold risk, roof damage from ice dams.

BC climate & code notes: Mixed‑humid coastal climate needs continuous air barrier, correct vapour control, and balanced attic ventilation. Interior and mountainous areas need enhanced ceiling insulation and air sealing to manage snow/ice.

Warning signs: Attic frost, blackened sheathing, bath fan ducts venting into attic, missing baffles at eaves, uneven insulation, ice dams at eaves, window condensation in winter.

Maintenance timeline: Check attic every season; clean/replace HRV/ERV filters every 3–6 months; service heat recovery ventilators annually.

When to call a pro: Visible mold on sheathing, chronic condensation, or unclear air/vapour barrier continuity—call building envelope specialist.

Real-life BC scenario: Kelowna home with recessed lights leaking air into attic causing winter ice dams; air‑sealing and baffles fixed it.

Homeowner action checklist:

• Add/repair soffit baffles; ensure clear airflow to ridge/roof vents.

• Air‑seal penetrations (top plates, light boxes) before adding insulation.

• Duct all exhaust fans outdoors with insulated ducting.

• Balance HRV/ERV and replace filters on schedule.

8) Leaky Building Envelope & Window Failures

Why it’s a red flag: Hidden rot and costly cladding/window replacements.

BC climate & code notes: Post “leaky condo” era construction typically uses rainscreen assemblies in coastal zones. Older stucco/EIFS and face‑sealed systems are high‑risk. Aluminum sliders (70s–80s) and failed IGU seals are common.

Warning signs: Bulged or cracked stucco, missing kickout/ head flashings, spongy sheathing at windows, fogged double‑pane glass, water staining at sills, decayed trim.

Maintenance timeline: Re‑caulk and repaint exposed trim every 3–7 years depending on exposure; plan window replacement at end of life (~20–30 years for many units).

When to call a pro: Recurrent leaks, soft walls, or cladding movement—call building envelope engineer or qualified contractor.

Real-life BC scenario: Richmond townhouse with face‑sealed stucco leaks at window heads; rainscreen retrofit recommended.

Homeowner action checklist:

• Inspect flashings at all openings; add kickout flashing where roof meets wall.

• Maintain caulking and paint; replace failed IGUs or windows.

• Verify cladding drainage gaps (rainscreen) during renovations.

9) Decks, Balconies & Exterior Stairs

Why it’s a red flag: Many injuries and water ingress originate here.

BC climate & code notes: Waterproof membrane decks (vinyl, torch‑on) are common on the coast; details at door thresholds, posts, and ledger flashing are critical. Guard/handrail height and spacing must meet current standards.

Warning signs: Soft spots, loose guards, rusted fasteners, improper post‑to‑concrete connections, ponding on membranes, missing ledger flashing, wood in contact with soil.

Maintenance timeline: Annual fastener/guard check; reseal membrane per manufacturer; recoat deck coatings as scheduled.

When to call a pro: Spongy feel, loose guards, or visible membrane failure—call qualified deck/membrane contractor.

Real-life BC scenario: Burnaby balcony with membrane turned only partway up wall; wind‑driven rain leaked into living room—flashing redo solved it.

Homeowner action checklist:

• Confirm ledger flashing and positive slope to drains.

• Replace corroded connectors with hot‑dip galvanized or stainless.

• Keep planters/grills off membranes; add protection pads.

• Ensure guards/handrails are secure and to current height/spacing.

10) Environmental Hazards: Asbestos, Lead, Radon, Oil Tanks, Mold

Why it’s a red flag: Health and liability risks; disclosure/insurance issues.

BC climate & code notes: Many pre‑1990 homes may have asbestos (vermiculite, vinyl tiles, drywall compound). Lead paint common pre‑1990. Radon is elevated in parts of the Interior and Northern BC. Buried heating oil tanks persist in older Lower Mainland/Island properties. Moist coastal climate supports mold growth in poorly ventilated spaces.

Safety warning: Do not disturb suspected hazardous materials. Testing and removal must be done by licensed professionals following BC regulations.

Warning signs: Popcorn ceilings, vermiculite in attic, 9×9 floor tiles, flaking old paint, musty odours, visible mold, unexplained soil pipes/fill caps (possible oil tank), high wintertime CO₂ and humidity.

Maintenance timeline: Radon test minimum 91 days in heating season; repaint/encapsulate intact lead paint surfaces; annual IAQ review if occupants are sensitive.

When to call a pro: Any suspected asbestos/lead, positive radon results (>200 Bq/m³), or oil tank discovery—hire licensed abatement, C‑Tec/Geo for radon mitigation, and certified tank removal contractors.

Real-life BC scenario: New Westminster home reveals vermiculite in attic; lab confirms asbestos—professional removal before insulation upgrade.

Homeowner action checklist:

• Order radon test kits for Interior/Northern regions or any ground‑contact basements.

• Scan property for oil tank indicators; check municipal records.

• Commission lab testing before renovations; use licensed abatement if positive.

• Address moisture sources first when remediating mold.

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