insulation (Home Systems)

Insulation

• What this is: the thermal envelope strategy for a BC home — covering the air-seal-first principle, R-value targets for Climate Zone 4 (Metro Vancouver), insulation types and where each fits, the rim-joist and crawlspace cases, comfort and energy-bill impact, and the BC Hydro / FortisBC / CleanBC rebate path. Applies to both strata units and detached homes, with strata scope flagged where it differs.
• Not: attic-specific ventilation, moisture, and pest detail (see attic (Home Systems)); crawlspace moisture management and encapsulation (see crawlspace (Home Systems)); heating and cooling equipment (see heating-system (Home Systems)); caulking and sealant detail (see caulking-seals (Home Systems)).
• Figures: 2025–26 Metro Vancouver estimates — get your own quotes.

Bottom line

The rule (tripwire)

• If you plan to add insulation → air-seal the assembly first. Insulation slows conductive heat loss; it does not stop air movement. Warm moist indoor air that leaks through gaps into a newly insulated (but un-sealed) assembly hits a cold surface, condenses, and creates mould and rot. Insulation added over air leaks can make moisture damage worse, not better.¹
• If your attic is below R-40 → upgrading to R-50 is the highest-return insulation move in Climate Zone 4. Attic heat loss is typically the biggest single gap; the installation is fast (under a day), and it qualifies for BC Hydro rebates.²³
• If you have an accessible crawlspace or basement rim joist → insulating the rim joist with closed-cell spray foam is an owner-doable quick win that cuts drafts, moisture risk, and heat loss simultaneously.⁴

Recurring upkeep

• Check insulation level and condition during your annual attic inspection (see attic (Home Systems)): look for compression, settlement, moisture staining, or displaced batts. Compressed insulation loses R-value fast — a batt compressed by 50% can lose more than half its thermal resistance.
• After any pest issue, water event, or renovation, inspect for disturbed or contaminated insulation in the affected zone before restoring finishes.

One-time setup

• Confirm your current R-value by measuring insulation depth in the attic and identifying material type. Metro Vancouver code minimum is RSI 6.91 (≈ R-40) for new work; recommended target for existing homes is R-50.²
• Pre-register for rebates before signing an insulation contract. BC Hydro and FortisBC require the contractor to be a registered HPCN (Home Performance Contractor Network) member; choosing a non-registered contractor voids the rebate.³⁵
• For a strata unit: confirm with your strata council before insulating. Building-envelope insulation (exterior walls, roof, building underside) is typically common property — the strata corporation’s responsibility and authority. In-unit insulation of interior partition walls or rim joists visible from your unit is generally owner scope, but the dividing line varies by strata plan.⁶

Standing facts

• Insulation installation does not typically require a standalone permit in BC for maintenance work (topping-up attic, replacing in-kind). If you are changing building envelope geometry, adding spray foam in a structural zone, or doing wall work as part of a permitted renovation, a permit may be required — confirm with your municipality.
• Dense-pack wall insulation and full spray-foam jobs require a licensed contractor. The spray foam equipment and blowing machines need operator training; wall penetrations for dense-pack involve drilling into framing and require precision fill-density to avoid wall bulge.

How it works — the one thing that matters

Heat moves by three mechanisms — conduction, convection, and radiation. Insulation addresses conduction only. An R-50 attic does nothing to stop air that leaks through a gap around a pot light and carries warm, humid air into the cold attic space.

The building-science sequence:

1. Air leaks first. Warm indoor air is also moist indoor air. When it travels through a gap in the building envelope, it cools as it moves outward. Once it reaches the dew point, the water vapour condenses on whatever cold surface it touches — typically the underside of sheathing or the inner face of exterior walls. This is the direct moisture pathway. Joseph Lstiburek’s work at Building Science Corporation established that “adding air-permeable insulation to a stud space increases condensation risk” if air leaks haven’t been sealed first — because the insulation moves the cold condensation surface closer to the interior dew point while the air leak is still active.¹

2. Then insulate. Once gaps are sealed, insulation does its job: it slows the rate of conductive heat transfer through the assembly, keeping more heat inside in winter and outside in summer. R-value is an additive property — doubling R-value halves conductive loss.

3. Vapour control last. A vapour retarder (poly sheet, vapour-barrier paint) slows moisture diffusion through the assembly. In BC’s temperate coastal climate (Climate Zone 4), vapour drive is relatively low compared to colder zones, but it still matters: vapour retarder goes toward the warm side of the assembly (interior in winter-dominated climates), and its class (permeance) needs to be right for the wall assembly design.

So what: skipping air sealing and going straight to insulation is the single most common insulation mistake in BC older homes. The correct order is always: seal → insulate → verify vapour control.

→ Air-Seal-Before-You-Insulate — Insulation-Over-Leaks-Makes-Moisture-Worse (Home Systems)

What goes wrong, and the warning signs

Watch for	What it means
Frost or dark staining on attic sheathing in winter	Warm moist air condensing on cold sheathing — air leak above, insufficient insulation, or both
Musty smell or visible mould on wood framing in attic	Condensation has been occurring long enough for fungal growth — pro remediation needed
Cold floors over a crawlspace in winter	Rim joist or crawlspace ceiling insulation is absent, thin, or fallen
Drafts at baseboard level or near exterior walls	Air bypassing insulation through framing gaps, electrical penetrations, or settling
Ice dams at the eave edge (detached with attic)	Attic heat melting snow; snow re-freezes at the cold overhang — thermal bridging or air leak in the attic floor
Higher than expected heating bills after insulation work	Air sealing was not done first; the insulation is performing at less than its rated R-value
Compressed, sagging, or water-stained batts	Past moisture event or insufficient vapour control; the insulation may have been wet and dried in place, retaining mould spores
Wall bowing or bulging after dense-pack	Over-dense fill — installer error; a structural concern if severe
Yellow or brown foam around rim joists that is crumbling	Old polyurethane foam past service life; needs replacement

What actually fails (the load-bearing failure):

• Air-leakage-driven moisture condensation in the assembly — the dominant failure mode. Produces mould, rot, reduced R-value, and structural wood damage if left long enough.
• Settlement and compression in blown-in insulation (especially older cellulose or vermiculite) — the R-value you installed is not the R-value you have today.
• Pest-damaged insulation — rodents and insects tunnel through batt insulation, compressing and contaminating it. A pest issue always precedes any insulation work.³
• Asbestos-containing insulation in pre-1990 homes — vermiculite attic insulation (common pre-1990, particularly in older Metro Vancouver housing stock) may contain asbestos. Do NOT disturb it without a Professional Industrial Hygienist assessment.

When to replace vs repair

What you see	Do this
Insulation is below R-40 (Climate Zone 4 minimum)	Upgrade — add blown-in on top; no removal needed in most cases
Insulation is compressed but dry and intact	Supplement — blown-in over the existing layer recovers most of the lost R-value
Moisture-stained or mouldy insulation	Remove and replace — mouldy insulation cannot be remediated in place
Vermiculite (grey, pebble-like granules) in attic	Test for asbestos before touching — remediation by a certified abatement contractor
Rodent-contaminated insulation (droppings, odour, nesting)	Pest control first, then full removal and replacement — you cannot encapsulate contamination
Wall insulation missing or thin (confirmed by thermal scan)	Dense-pack retrofit — specialist contractor, wall penetrations; not DIY
Rim joist insulation absent or degraded	Replace with closed-cell spray foam or rigid + canned foam — owner-doable
Spray foam with surface crumbling or chalking	Replace — aged foam loses cohesion and adhesion

Verdict: most insulation decisions are reversible (new material can always replace old) and the cost range spans from DIY-affordable (rim joist, <$200inmaterials)toexpensivepro-only(walldense-pack,$3,500–$5,500foramainfloor{[}^5]).ThedecisionsthatcrossboththeirreversibleAND>$500 threshold are:

• Full wall insulation retrofit with exterior cladding removal — the cladding cannot be re-installed identically; once you open the wall, there is structural and moisture-management work that follows.
• Complete attic insulation removal and replacement (for asbestos or major pest contamination) — typically $4,000–$10,000+ depending on extent and hazard.

Both warrant the full The Decision Lifecycle treatment before committing.

→ Attic-Is-the-Biggest-Bang-for-Buck-Insulation-Zone-in-BC-Climate-Zone-4 (Home Systems)

Typical cost (BC / Metro Vancouver)

Tier	What’s included	Range	Sources
DIY / parts only	Rim joist: rigid foam board (e.g. 2” XPS, R-10) + canned spray foam sealant; owner-cut and installed	$100–$300 for a typical perimeter	47 — indicative (limited sources)
Basic	Attic blown-in top-up (cellulose or fiberglass) to R-50, over existing; HPCN contractor, no removal; minimum scope for BC Hydro rebate eligibility	$1,200–$2,800 for 1,000–1,500 sq ft attic	8910
Standard	Attic blown-in to R-50–R-60 with ceiling-plane air sealing (canned foam at penetrations, weather-strip attic hatch); pro rim-joist spray foam (closed-cell, R-20+); HPCN-registered contractor	$2,500–$5,000 combined attic + rim joist	48911
Premium / complex	Dense-pack wall cavity retrofit (cellulose/fiberglass through drilled holes, no drywall removal) for main floor of detached home; or full attic insulation removal + replacement (contaminated or asbestos material handled by certified contractor)	$3,500–$10,000+ depending on scope and hazard	91210

Metro Vancouver runs at the higher end of national Canadian ranges — add approximately 10–20% vs Prairie cities. Spray foam (closed-cell) in BC runs $2.95–$4.75 per sq ft installed.¹¹ Blown-in cellulose or fiberglass runs approximately $1.40–$3.60 per sq ft installed for attic top-ups.¹⁰ Removal of old attic insulation (no contamination) adds $1.00–$2.50 per sq ft.¹² Contaminated or suspected-asbestos removal is separate, highly variable, and requires specialist assessment first.

Rebates can substantially reduce net cost: BC Hydro offers up to $900foratticinsulationandupto$1,200 for basement/crawlspace and wall insulation; FortisBC offers up to $1,200 total for qualifying insulation upgrades; low-income households may receive 60–95% off through CleanBC.³⁵ A registered HPCN contractor is mandatory for all rebate streams.

How to maintain it — the procedures

Insulation does not require active maintenance once installed correctly. Owner procedures are inspection, identification, and knowing when to call a pro.

Procedure: Annual insulation inspection — attic and crawlspace

Why: insulation can be compressed by pest activity, displaced by water events, or degraded without visible exterior symptoms. An annual visual check catches problems before they become structural.

You’ll need: flashlight, tape measure, notepad; 15–30 min per space.

1. For the attic: open the hatch and look from the opening before entering. Shine the flashlight across the insulation floor — uniform depth, no sagging, no dark staining, no droppings.
2. MUST NOT walk on exposed joists; use a crawl board or stay at the hatch. Stepping on insulation compresses it and loses R-value permanently.
3. Check depth with a ruler at three locations: centre, near eave, near attic hatch. Depth × R-value per inch (batts: ~R-3.5/inch fiberglass; blown cellulose: ~R-3.7/inch; spray foam closed-cell: ~R-6/inch) = approximate effective R.
4. For the crawlspace: inspect for fallen batt insulation between floor joists (common after pest activity), moisture on wood surfaces, and the condition of any rim-joist insulation.
5. Note the date, estimated R-value, and any anomalies.

Done when: you have a current written note of insulation type, depth, and any concerns.

Stop and call a pro if:

• Vermiculite present (grey pebble-like granules) — do not touch; arrange asbestos assessment
• Mould or rot on wood adjacent to insulation
• Pest droppings throughout the insulation — pest remediation before any insulation work
• Moisture staining covering >1 sq ft of area

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Procedure: Rim joist insulation — owner-doable upgrade

Why: the rim joist is the band of framing that sits on top of the foundation and closes off the floor cavity at the perimeter. It is typically uninsulated or poorly insulated in older BC homes, and is a major cold-air infiltration point in detached homes and some strata row-houses.

You’ll need: 2” rigid foam board (XPS or polyiso), utility knife and straight edge, canned spray foam (Great Stuff or equivalent), safety glasses, dust mask; 2–4 hours.

1. Locate the rim joist — it is the vertical band visible just above the top of the foundation wall in the basement or crawlspace.
2. MUST confirm no plumbing, electrical, or HVAC runs through the bay you’re about to insulate.
3. Measure each bay between joists; cut a friction-fit piece of 2” rigid foam to fill the cavity snugly (aim for less than 1/4” gap on all edges).
4. Press the foam piece into the bay. Run a bead of canned spray foam around all four edges to seal air gaps.
5. Repeat for each bay around the perimeter.

Done when: foam board is flush in each bay, edges sealed with spray foam, no visible gaps.

Stop and call a pro if:

• You find pest evidence (rodent entry holes, droppings) in the rim joist zone — pest control first
• You find rot or moisture damage on the rim joist lumber — structural repair before insulating
• The rim joist is part of a complex framing situation (staggered, balloon-frame) — a specialist can confirm the assembly

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Procedure: Calling a pro for blown-in attic insulation top-up

Why: if your attic is below R-40 (Climate Zone 4 minimum), a blown-in top-up is the single highest-impact home performance move available in Metro Vancouver. This is pro-only because of equipment requirements (blowing machine) and rebate eligibility (HPCN contractor required).

You’ll need: nothing — the contractor supplies equipment and material.

1. MUST resolve any pest activity or moisture issues before the contractor arrives — most HPCN contractors and BC Hydro rebate terms require this.
2. Confirm the contractor is HPCN-registered before signing the quote (ask for their registration number or check at betterhomesbc.ca).
3. Confirm the scope includes ceiling-plane air sealing at accessible penetrations (pot lights, attic hatch, plumbing and electrical chases) — this is the step most quote-shoppers miss.
4. Confirm the target R-value in writing (minimum R-50 for Metro Vancouver existing homes is the practical standard).
5. Apply for the BC Hydro rebate within 6 months of the invoice date.

Done when: installed depth measured at multiple points matches the target R-value; air sealing at penetrations is confirmed.

Stop and call a pro if:

• Any sign of pest damage or mould — must be cleared first
• Bathroom fans terminate in the attic — must be rerouted before insulation is added

Maintenance calendar:

• Annually (fall): attic and crawlspace visual check — depth, moisture, pest signs.
• After any plumbing, electrical, or renovation work in the attic or crawlspace: confirm insulation was not displaced or contaminated.
• After any pest event: call pest control first; then insulation inspection and replacement if needed.
• On purchase of an older home (pre-1990): assess for vermiculite (asbestos risk) before any attic work; check wall and attic R-values; schedule an HPCN energy assessment to set the upgrade roadmap.

Strata reality

What’s yours vs the strata’s — the building-envelope split

In a BC strata, insulation responsibility tracks where the insulation physically sits:

• Building envelope insulation (exterior walls, roof assembly, building underside including the ceiling of a crawlspace or parkade below a unit) — this is the strata building envelope and is common property under SPA s.72. The strata corporation is responsible for it; BC courts have confirmed this applies to insulation that straddles the lot boundary.⁶ You cannot unilaterally upgrade or modify it.
• In-unit partition wall insulation (interior walls between rooms, party walls between units) — this is more complex. The insulation inside a demising wall may be common property or part of both lots depending on the strata plan. Check your registered strata plan and bylaws before touching it.
• Rim joist insulation accessible from your unit’s basement or crawlspace storage — if the rim joist is within your strata lot boundary (typically confirmed by the strata plan), you may be able to insulate it; if it is in limited common property or common property (e.g., shared parkade perimeter), it is the strata corporation’s scope. Confirm before starting.

Rebate eligibility in strata: BC Hydro / FortisBC rebates are available to strata owners for insulation within their unit (e.g., underfloor exposed floor insulation, rim joist in your own crawlspace storage). Building-envelope upgrades require strata council approval and would typically need the strata corporation to apply on behalf of all affected units.

Relevant SPA provisions:

• SPA s.72 — strata corporation’s duty to repair and maintain common property, including building envelope
• Standard Bylaw 2 — owner’s duty to maintain their strata lot
• Standard Bylaw 8 — owner must obtain strata council approval before any alteration to common property or limited common property

SPA s.158¹³ water-damage chargeback context: insulation itself is rarely a direct s.158 trigger, but a failed vapour barrier or improperly installed spray foam that causes moisture damage to common property or another unit can trigger the strata deductible chargeback process. Any insulation work affecting the building envelope should be permitted, documented, and done by an HPCN-registered contractor so you have a paper trail. → The Strata Insurance Circularity Problem

When you hire someone

Ask:

• Are you registered with the Home Performance Contractor Network (HPCN)? (Required for any BC Hydro / FortisBC rebate; ask for the registration number.)
• Will you complete the BC Hydro rebate application on my behalf, or do I need to submit it?
• Does your scope include ceiling-plane air sealing at penetrations, or is that quoted separately?
• What target R-value will you install, and how will you verify it (depth gauge readings, invoiced material quantity)?
• Is removal of existing insulation included or separately quoted?
• How do you handle finding mould, pests, or suspected asbestos during the job?
• Do you provide a written warranty on labour and materials?

Verify the work:

• Written confirmation of target R-value achieved (depth measurements at 3+ locations, or installed material quantity / coverage rate from the bag label)
• Ceiling-plane air sealing completed at hatch, pot lights, plumbing/electrical chases
• Ventilation baffles present at the eaves to maintain minimum 63 mm clearance above insulation (for vented attics)
• No compressed insulation directly against the hatch (hatch should be separately insulated and weather-stripped)
• Rebate application submitted or handed to you to submit within 6 months of invoice
• No lingering musty smell after project completion (which could signal disturbed mould)

Who to call

These become real when filled in the Tier-B MOCs:

• HPCN-registered insulation contractor → vendor-roster (Home Systems). Fill: company name, HPCN registration number, phone, whether they handle rebate applications, and experience with attic air sealing.
• EnerGuide / energy advisor (for multi-upgrade rebate packages): HPCN energy advisors conduct pre- and post-upgrade assessments when bundling 3+ upgrades for the CleanBC bonus rebate. Find via betterhomesbc.ca → vendor-roster (Home Systems). Fill: advisor name + accreditation number.
• Asbestos / abatement contractor (if vermiculite found): a separate specialization from general insulation. → vendor-roster (Home Systems). Fill: company, certification, whether they handle both testing (PHI assessment) and removal.
• Strata manager / council → Strata MOC. Fill: process for getting written strata approval before any envelope-adjacent insulation work.

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Sources

Idea Compass

North: Where this comes from

• Structural (Home Systems) — parent system
• Building Science Corporation (Lstiburek) — the air-sealing-first principle that underpins the entire field
• BC Building Code s.9.36 / Climate Zone 4 prescriptive tables — the regulatory baseline for R-value targets

East: Tensions / failure

• Air-Seal-Before-You-Insulate — Insulation-Over-Leaks-Makes-Moisture-Worse (Home Systems) — the dominant failure mode
• Vapour diffusion vs air leakage: in BC’s marine climate the air-leakage vector is 100× more impactful than diffusion — the vapour barrier is secondary, not primary
• Cost-rebate structure: HPCN contractor requirement means cheapest contractor is not eligible; discount bids often skip air sealing

South: Where this leads

• attic (Home Systems) — the highest-bang-for-buck upgrade zone in detail
• crawlspace (Home Systems) — rim joist and crawlspace ceiling insulation detail
• heating-system (Home Systems) — insulation and air sealing reduce heating load; what you spend on envelope you save on HVAC
• vendor-roster (Home Systems) — the HPCN contractor named-resource card

West: What’s similar

• caulking-seals (Home Systems) — the air-sealing side of the same envelope strategy (caulk = small gaps; spray foam = larger voids; insulation = field between)
• windows (Home Systems) — another building-envelope element where air sealing around the frame outweighs the glass U-factor for older windows
• Balanced Soffit-to-Ridge Airflow Keeps the Attic Cold and Dry (Home Systems) — ventilation as the complement to insulation in the attic assembly

Footnotes

1. Building Science Corporation (Joseph Lstiburek), building-science digest BSD-163 — “adding air-permeable insulation to the stud space increases the risk of condensation” when air leaks are present; condensation is primarily driven by air leakage, not vapour diffusion — https://buildingscience.com/documents/digests/bsd-controlling-cold-weather-condensation-using-insulation ↩ ↩²

2. Paragon Roofing BC, Metro Vancouver roofing contractor — attic insulation in Vancouver: BC Building Code prescribes RSI 6.91 (≈ R-40) minimum for Climate Zone 4; industry target for existing homes is R-50–R-60; cathedral ceilings require approximately R-26–R-28 — https://www.paragonroofingbc.ca/blog/attic-insulation-ventilation-in-vancouver-r-values-moisture-mould ↩ ↩²

3. BC Hydro / BetterHomesBC, the provincial electric utility and rebate program — insulation rebate amounts: attic $0.02\times R-valueadded\times sqft(max$900); basement/crawlspace $0.09\times R-valueadded\times sqft(max$1,200); exterior wall cavity $0.09\times R-valueadded\times sqft(max$1,200); HPCN contractor mandatory; minimum R-values: attic R-12, basement/crawlspace R-10, exterior wall R-12; application within 6 months of invoice — https://www.bchydro.com/powersmart/residential/rebates-programs/home-renovation/renovating-insulation.html ↩ ↩² ↩³ ↩⁴

4. MUS Energy, insulation contractor — rim joist insulation in Canada: closed-cell spray foam recommended for moisture resistance; professional spray foam averages $2–$5/sq ft; rigid foam DIY approach described — https://mus-energy.com/rim-joist-insulation-canada/ ↩ ↩² ↩³

5. FortisBC, the provincial natural gas utility — insulation rebates up to $1,200; qualifying upgrades under the Home Renovation Rebate Program (HHRR) jointly administered with BC Hydro and CleanBC — https://www.fortisbc.com/rebates/detail/insulation-rebates ↩ ↩²

6. Province of BC, BC government — division of repair duties in a strata: strata corporation responsible for repair and maintenance of common property including building envelope (SPA s.72); Standard Bylaw 2 (owner scope) and Standard Bylaw 8 (owner alteration approval) — https://www2.gov.bc.ca/gov/content/housing-tenancy/strata-housing/operating-a-strata/repairs-and-maintenance/division-of-repair-duties ↩ ↩²

7. Reno Quotes, Canadian renovation cost guide — rigid foam board materials: $1.50–$8.00/sq ft by type (EPS, XPS, polyiso); fiberglass batt: $0.90–$5.90/sq ft; cellulose: approximately $1.00/sq ft material only — https://renoquotes.com/en/blog/insulation-cost ↩

8. Walker General Contractors, Metro Vancouver renovation contractor — attic insulation to R-60 for a 1,200 sq ft attic in Metro Vancouver: $2,800–$4,200; dense-pack wall insulation (no drywall removal): $3,500–$5,500 for a main floor — https://walkergeneralcontractors.ca/energy-efficient-home-renovations-in-metro-vancouver/ ↩ ↩²

9. Multiple Canadian cost sources: HomeguideCanada and HomeAdvisor (US-sourced, flagged indicative) — blown-in attic insulation Canada-wide: $1.40–$3.60/sq ft installed; $1,200–$3,500 for 1,000–1,500 sq ft attic; removal of clean old insulation: $1.00–$2.50/sq ft; contaminated or wet insulation removal: $2,000–$3,500 for 1,000 sq ft — https://homeguide.com/costs/attic-insulation-cost ↩ ↩² ↩³

10. HomeGuide.com, US-based cost aggregator (flagged: US-sourced, treat as indicative floor; Metro Vancouver adds 10–20%) — blown-in insulation installed: $1.00–$2.80/sq ft; typical 1,000–1,500 sq ft attic: $900–$3,600 — https://homeguide.com/costs/blown-in-insulation-cost ↩ ↩² ↩³

11. BhumiCalculator, Canada-wide cost guide — spray foam insulation BC: open-cell $1.60–$2.40/sq ft; closed-cell $2.95–$4.75/sq ft; BC market listed as “increasing” trend for 2026; typical 1,500 sq ft closed-cell project: $4,100–$7,350 total — https://bhumicalculator.com/countries/canada/spray-foam-insulation-cost-per-sq-foot ↩ ↩²

12. Advance Insulation Canada, BC insulation contractor — attic insulation removal cost in Canada: $1.00–$2.50/sq ft; wet/mouldy insulation $2.00–$3.00/sq ft; rodent-infested $2.50–$3.50/sq ft; vermiculite/asbestos $4.00–$10.00+/sq ft by specialist — https://advanceinsulation.ca/how-much-does-attic-insulation-removal-cost-a-homeowners-pricing-guide/ ↩ ↩²

13. Strata Property Act (BC Laws) — the governing statute (incl. ss. 135, 158, 164) — https://www.bclaws.gov.bc.ca/civix/document/id/complete/statreg/98043_09 ↩