What a basement
renovation costs
in Chilliwack.

Basement renovation is one of the most varied project types in Chilliwack. The same 800 square feet of unfinished space can become a $40K rec room or a $140K legal secondary suite depending on what the space needs to do, what it must meet by code, and what condition the existing basement is in.

This post walks through four scope tiers with real 2026 numbers, what drives the difference between them, and the hidden costs that catch most homeowners off-guard.

The five factors that drive basement cost

1. Legal suite vs. unfinished space. A legal suite has significantly more code requirements than a simple rec room: separate entrance, code-compliant egress windows, fire-rated separation, sub-panel, full kitchen plumbing. These requirements typically add $40K to $60K on top of basic finishing.
2. Existing moisture conditions. A dry basement is cheaper to renovate than one with active moisture, efflorescence, or past water damage. If perimeter drainage or a sump pump is required before finishing, that can add $5K to $15K.
3. Ceiling height. BC Building Code requires 7 feet minimum for habitable rooms. Older Chilliwack homes sometimes come in at 6 foot 10, which can require excavation or a different suite configuration.
4. Plumbing scope. A new below-grade bathroom typically needs an ejector pump to lift waste up to the main drain line. That adds $3K to $6K beyond standard bathroom plumbing.
5. Electrical service capacity. Many 1970s and 1980s Chilliwack homes have 100-amp services that cannot support adding a legal suite. The service upgrade (100A to 200A) is $3K to $5K in Chilliwack 2026.

Four Chilliwack basement tiers, with real numbers

Tier 1: Basic finish

$35,000 – $60,000

Open rec room, minimal bathroom additions (or none), standard flooring, paint, baseboards, lighting. No legal-suite requirements. Perfect for turning unfinished space into a functional extra living area without major plumbing or kitchen scope. Timeline: 6 to 10 weeks.

Tier 2: Finished basement

$60,000 – $100,000

Framing, drywall, flooring, bathroom addition with ejector pump, bedroom with egress-code window, rec room, laundry relocation possible. Proper moisture management and insulation. No separate suite, but a genuine second level that adds meaningful space and resale value. Timeline: 8 to 12 weeks.

Tier 3: Legal secondary suite

$100,000 – $150,000

Full legal suite build under the BC Building Code: separate entrance, code-compliant egress windows, fire-rated separation between suite and main home, separate electrical sub-panel, independent heating and ventilation, full kitchen, bathroom, bedroom or bedrooms, laundry. Permit coordination and inspections through to occupancy approval. Timeline: 10 to 16 weeks.

This tier is the most common call we get in Sardis, Vedder Crossing, and Promontory, where the combination of family homes and strong rental demand makes a legal suite a high-ROI move.

Tier 4: Premium or complex

$150,000 – $300,000

Two-bedroom legal suite, wet bar, home theatre room, significant structural changes, excavation to increase ceiling height, major moisture remediation combined with finishing, or a legal suite paired with a large rec room build-out for the main home. Timeline: 14 to 22 weeks.

What makes a legal suite cost more than a finished basement

The $40K to $60K jump from Tier 2 to Tier 3 is not arbitrary. Here is where that money goes:

• Fire separation. 45-minute or 60-minute fire-rated walls and ceiling between the suite and the main home. Usually double layer drywall with resilient channel, or Type X drywall. Adds about $4 to $6 per square foot of separation surface.
• Egress windows. Every legal bedroom requires a code-compliant egress window. Cutting concrete foundation, excavating the window well, installing the window, waterproofing, and restoring drainage runs $3K to $5K per window.
• Separate electrical sub-panel. A dedicated panel for the suite, separate from the main home. Plus the main service upgrade if the house is on 100 amps. Total electrical premium for a legal suite: $8K to $15K.
• Full kitchen. Cabinets, counters, sink, dishwasher, range, fridge, range hood with proper exterior venting. $10K to $25K depending on finish level.
• Interconnected smoke and CO detectors.Required to be hardwired and interconnected between units.
• Permit and inspection overhead. Building permit, electrical trade permit, plumbing trade permit, occupancy inspection, multiple mid-project inspections. $1,500 to $3,000 in fees plus project management time.

Where flood construction level changes everything

Parts of Chilliwack sit below the flood construction level (FCL) established in the Floodplain Regulation Bylaw. This applies primarily in Fairfield Island, Greendale, and lower Yarrow. On these properties, new secondary suites cannot be built below the FCL.

What that means practically: on a 1970s rancher in lower Fairfield Island with a slab-on-grade foundation, a legal basement suite is often not possible. A coach house, a main-floor suite addition, or an above-garage suite becomes the path forward instead. We check the FCL against your lot before scope discussions get specific.

Bill 44 (SSMUH) and what it changed

In 2024, BC passed Bill 44 and Chilliwack implemented the Small-Scale Multi-Unit Housing amendments. On single-detached and duplex lots greater than 280 square meters inside the Urban Growth Boundary, up to four units are now permitted.

What this means for basement suites: many more Chilliwack lots can now legally support a basement suite plus a coach house, or convert to a duplex plus a secondary suite. This expanded what is possible, but it did not change the code requirements. Legal suites still have to meet BC Building Code for fire separation, egress, and mechanical separation.

Where the money actually goes on a legal suite

For a typical Tier 3 legal suite at around $125,000:

• Framing and fire separation: 18 to 22 percent
• Electrical (sub-panel, circuits, service upgrade): 8 to 12 percent
• Plumbing (supply, drain, ejector, fixtures): 10 to 14 percent
• Kitchen (cabinets, counters, appliances): 15 to 20 percent
• Bathroom (tile, vanity, fixtures): 8 to 12 percent
• Flooring (vinyl plank or engineered hardwood): 5 to 7 percent
• Egress windows and entrance: 5 to 8 percent
• Drywall, paint, finishing: 8 to 10 percent
• HVAC, ventilation, smoke alarm interconnect: 3 to 5 percent
• Permits and project management: 3 to 5 percent

The ROI math

A Chilliwack legal secondary suite typically rents for $1,500 to $2,700 per month depending on size and finish. Using the middle of that range ($2,100) against a $120K build:

• Annual gross rent: $25,200
• Simple payback (ignoring property value lift and mortgage bonus): 4.8 years

After payback, the rent is margin. Your accountant will want to look at depreciation, vacancy, maintenance, property management if applicable, and the primary-residence exemption rules. But the simple payback math is why suite builds are one of the most common renovations we quote.

The hidden costs most quotes miss

• Service upgrade. If the existing home is on 100 amps, a legal suite usually pushes it over capacity. The upgrade to 200 amps runs $3K to $5K.
• Ejector pump for below-grade bathroom.Required on most Chilliwack basement bathrooms because the basement floor is below the main drain line exit. $2K to $4K for the pump and vent routing.
• Moisture remediation. If the basement has any existing moisture problem, we solve it before framing. Perimeter drainage, sump pump, or vapor management. $5K to $15K depending on severity.
• Egress window excavation. Each new egress window needs the concrete foundation cut, the window well dug and drained, and the window installed and waterproofed. $3K to $5K per window.
• Short-term rental restrictions.BC's short-term rental legislation (effective May 2024) restricts Airbnb-style rentals in Chilliwack to principal residences plus one secondary suite. If your plan is to buy a second property and Airbnb the suite, that is not legal in Chilliwack.

The bottom line

A Chilliwack basement renovation in 2026 runs anywhere from $35K for a basic finish to $300K+ for a premium legal suite build with complex structural work. The sweet spot for most homeowners is the $100K to $150K legal suite tier, which produces a long-term income stream that pays itself back in five to eight years.

Because our Red Seal electricians and plumbers are Huntley employees, legal suites run on one coordinated schedule rather than waiting for separate trade companies. Permit coordination with the Chilliwack Building Department happens through one project manager. That is the difference between a suite that takes 12 weeks versus 20.