Legal secondary suites for rental income, coach houses, above-garage units, and home additions. From the older Mission City heritage core to the Cedar Valley and Silverdale slopes, built onto the home you already own. In-house Red Seal trades, engineering coordination, and District of Mission permits handled end to end.
12 mo
Workmanship Commitment
Every trade we put on the suite, covered for a full year.
Red Seal
In-house electrical & plumbing
Both trades on the Huntley payroll, not subcontracted.
Up to 4 units
On qualifying lots
Per Mission SSMUH zoning under Bill 44.
One PM
Running every trade
One schedule, one point of contact, one accountable team.
Quick Answer
Legal suites and additions in Mission run $100K to $150K for a basement suite conversion, $150K to $300K for a rear addition, and $300K to $500K+ for a second-storey addition or coach house. Engineering, permits, and in-house Red Seal trades handled end to end. The District of Mission has adopted SSMUH zoning under Bill 44, which can allow up to three or four units on qualifying lots in the urban area. Line-item quotes, no blanket allowances.
Legal suites in Mission
Mission sits across a wide spread of housing eras, and a legal suite reads that history. The Mission City heritage core holds pre and post-war hillside homes. Cedar Valley and Silverdale carry 1980s and 1990s graded lots with walk-out basements. Around Hatzic Lake the rules tighten near the water. Stave Falls and Hatzic Prairie are rural acreage. The path to a legal suite changes meaningfully by where the home sits.
On the older heritage-core stock, a basement suite is rarely just drywall and a kitchen. Knob-and-tube wiring, galvanized supply lines, and gravity furnaces mean the suite triggers a panel and circuit rewire, a repipe, an egress window cut, and code-compliant fire separation. We build those mechanical realities into the scope at the site visit rather than discovering them mid-project.
On the Cedar Valley and Silverdale slopes, the walk-out basements often already have the daylight and separate entry a grade-level suite wants. There the work leans toward the reconfiguration and finish, with retaining walls and drainage routing planned around how water moves across the graded lot.
A legal suite is where coordination matters most, because the electrical, plumbing, fire separation, and egress all have to pass inspection together. At Huntley, our framers, Red Seal electricians, and Red Seal plumbers work for the same company. The rough-in coordination happens on site, not on a three-way phone call between separate trades. One project manager runs the whole path on one schedule.
The Mission suite context
Mission is not one housing market. A basement suite in a heritage-core home is a different project from a grade-level suite on a Silverdale slope or a coach house near Hatzic Lake. Riparian setbacks, ALR rules, and the age of the home shape what is possible. We plan each one for the property in front of us.
Pre and post-war hillside homes here often carry knob-and-tube wiring, galvanized supply lines, and gravity furnaces. Legalizing a basement suite in this stock is a mechanical upgrade as much as a finish job: a panel and suite circuit rewire, a repipe off the galvanized lines, an egress window cut, and code-compliant fire separation. We scope that mechanical reality into the project at the site visit, not at rough-in.
1980s and 1990s graded hillside lots with walk-out basements suit grade-level, separate-entry legal suites well. The lower level often already has the daylight and the door location a suite needs. Retaining walls and drainage routing factor into any lower-level reconfiguration, so we plan the suite around how water moves across the lot.
Riparian setbacks and foreshore rules constrain detached coach houses and any change to the building footprint near the water. Lake-effect humidity drives moisture management and finish-grade selection inside a suite, so we specify materials and ventilation for the conditions rather than defaulting to a standard basement build.
Wells, septic, propane, and ALR shape every rural quote. Septic field capacity limits how many added units a property supports. ALR designation restricts accessory dwellings on agricultural-zoned land. Well flow affects whether a second kitchen and bathroom are workable. We verify all of it before scope discussions get specific.
What's in scope
Down, out, up, or detached. We run every permit path and every trade for all of them, with one point of contact and one company accountable from feasibility through handover.
Converting unfinished or partially finished basement space into a legal secondary suite. Separate entrance, code-compliant egress, fire separation, sub-panel, full kitchen, full bathroom. On older Mission City homes this is as much a mechanical upgrade as a finish job. Permit coordination and inspections through occupancy.
Detached secondary dwellings in the backyard. A coach house can serve as rental income, in-law housing, a home office, or a studio. We handle the District of Mission permit path, the servicing trench for water, sewer, and electrical, and the build itself, including off-street parking that the new dwelling needs.
A self-contained suite above an existing or new garage. Requires structural reinforcement of the garage below, exterior stair access or integrated entry, a full mechanical run up to the unit, and a zoning review depending on the lot. A practical option on Cedar Valley and Silverdale lots where the basement does not suit a separate entry.
Extending the main floor out the back of the home. Family rooms, primary suites, kitchen expansions, sunrooms. Foundation work, framing, envelope, mechanical extensions, and finish. Often easier than going up because the roof stays put, and it can add the square footage a suite or in-law setup needs.
Adding a full or partial second floor on top of your existing home. Structural capacity assessment first, engineering coordination, roof removal, framing the new level, mechanical extensions, and full finish. A way to add living space, or a separate upper unit, without losing your lot footprint.
Any legal suite or addition requires structural engineering, trade permits, and a building permit through the District of Mission. We coordinate engineers we have worked with, pull our own electrical and plumbing trade permits directly, and take the building permit path end to end so you are not chasing the District.
A new building stuck to the old one.
The seam is where it counts.
A legal suite or addition fails at the integration, not the build. How the new work ties into an older Mission home without leaks, cold bridges, or a failed inspection is the real job. Framers, Red Seal electricians, and Red Seal plumbers under one payroll, run by one project manager, is how that seam holds.
How a Huntley suite gets built
We walk the Mission home, look at structural capacity (can it take a second storey?), measure setbacks, check the electrical service and plumbing, and review septic or sewer capacity. We check zoning against what you are trying to build. Some suites are a straightforward conversion. Some need engineering or a riparian or ALR review. We tell you honestly which category yours is in.
Architectural or designer drawings, structural engineering for load paths and foundations, mechanical upgrade plans, septic or sewer review where it applies. On heritage-core homes we plan the rewire, repipe, and egress work alongside the finish. Finish selections and fixture specifications locked before permit submission.
Building permit through the District of Mission, trade permits for electrical and plumbing pulled directly by our in-house Red Seal trades, and any zoning, riparian, or ALR approvals the scope requires. Long-lead materials and fixtures ordered early against the build schedule.
For a basement suite: egress, fire separation, sub-panel, kitchen, bathroom, separate entrance, and the mechanical upgrades the older home needs. For a coach house or garden suite: servicing trenches and foundation first, then framing, roof, envelope, mechanical, and finish. One project manager runs the whole sequence on one schedule.
Final inspections, mechanical commissioning, deficiency walk-through, and handover of manuals and warranty documents. The 12-month Huntley Workmanship Commitment begins from handover and covers every trade that worked on the project.
Honest numbers
Most contractors will not publish real numbers on suites and additions because the scope varies so much. We will, because clients who understand ranges make better decisions. These are typical Mission project bands by scope. Final quote is line-itemed after the site visit.
Basement suite conversion
$100K – $150K
Converting existing basement space into a legal secondary suite. Egress windows, fire separation, sub-panel, full kitchen and bathroom, separate entrance. No foundation work, no envelope work. On older Mission homes, add for the rewire and repipe the suite triggers.
Rear addition
$150K – $300K
Extending the main floor out the back. Foundation, framing, envelope, mechanical extensions, interior finish. Scope depends on size and whether the addition adds a bathroom or kitchen.
Second-storey / coach house
$300K – $500K
Adding a full floor above an existing home, or building a detached coach house or garden suite from scratch. Engineering, structural reinforcement, full envelope, mechanical, finish, and servicing.
Premium / complex
$500K+
Large second-storey additions with premium finishes, coach houses with multiple bedrooms and high-end materials, or combining a suite with whole-home renovation scope.
Typical Mission and Fraser Valley ranges, not quotes. Actual pricing depends on scope, existing conditions, engineering, servicing, and finish level. Suites in older Mission homes often include a panel rewire and repipe, scoped through our electrical division.
Real numbers, real scope
Site visit, check the zoning and the home, line-item quote. No pressure.
What to watch for
SSMUH zoning made it possible to add units on many Mission lots, which is genuine opportunity. It also made it possible for projects to fail in expensive ways at four specific points. Here are the ones we plan around on Mission properties.
SSMUH zoning is provincial under Bill 44, but the setbacks, parking minimums, and lot-coverage caps are set at the District of Mission level. The failure mode is a designer who draws the suite or coach house without confirming Mission’s local constraints first. The permit application gets denied, drawings are reissued, and the owner pays for design twice and waits another several weeks. The fix is a zoning pre-check before design. We do that with the District directly when we are involved at design stage.
Rear additions and detached coach houses both need foundations that work with the existing soil, slope, and drainage. On the Cedar Valley and Silverdale slopes, or the steeper grades around the Mission City core, soil bearing and slope stability can require an engineered foundation that adds meaningfully beyond a standard slab or crawlspace. The shortcut is to assume a standard footing and price accordingly. The fix is a geotechnical or engineering review at design stage, with the engineered scenario priced into the contract rather than discovered at excavation.
A detached coach house in Mission requires off-street parking for the new dwelling and a servicing path for water, sewer, and electrical. Lots without a clear parking solution or a workable servicing route cannot get a coach house permit. Near Hatzic Lake, riparian setbacks add a further constraint on where a detached building can sit. We confirm the parking pathway, servicing route, and any riparian setback at the first site visit, before any drawings start, rather than letting a design progress on a lot that ultimately cannot support it.
Where a new addition or suite meets the existing home, the building envelope has to integrate cleanly: roof tie-in, wall flashing, weather-resistant barrier, drainage plane. Most addition leaks happen at this seam, two or three years in, when wind-driven rain finds the discontinuity. Near Hatzic Lake the lake-effect humidity makes moisture management even less forgiving. The fix is detailed envelope coordination at framing stage with photo documentation before exterior finishes go on, so the new piece is one weatherproof structure with the existing home rather than two buildings stuck together.
Mission legal suite FAQ
The questions Mission homeowners ask us when they are weighing a legal suite, a coach house, or an addition. Straight answers on cost, timeline, SSMUH, permits, and the mechanical surprises in older homes before you sign with anyone.
Didn't see your question? Send us a message and we'll answer it directly.
Send a message →How we compare
A legal suite or addition is a renovation plus a new piece stuck to your existing home. Integration is where most projects fail. Here is how Huntley structures the work differently.
Typical Chilliwack contractor
Huntley Construction
Engineering coordination
Typical
Owner manages structural engineer separately from contractor
Huntley
We coordinate engineering and structural sign-offs directly
Permit path
Typical
Building, trade, and zoning permits each handled by different parties
Huntley
We pull the District of Mission building and trade permits directly, end to end
Older-home mechanical
Typical
Knob-and-tube and galvanized lines found mid-build, priced as change orders
Huntley
Panel rewire and repipe scoped at the first site visit
Envelope integration
Typical
New work leaks at the seam where it meets the existing home
Huntley
In-house team coordinating envelope, flashing, and water management
Coach house servicing
Typical
Owner coordinates trenching with the District, water, sewer, electrical separately
Huntley
Servicing trench planned and coordinated as part of the build
Workmanship warranty
Typical
Sub-trade dependent
Huntley
12-month commitment covering every trade that worked on the project
Related work
Kitchens
Layout changes, custom cabinetry, islands. In-house trades.
Bathrooms
Full rebuilds, custom showers, ensuites. In-house plumbing.
Basements
Finished basements, legal secondary suites, rec rooms.
Keep researching
Plain-English guide to legal suite zoning, egress, and permits.
Read postWhich option fits your lot, and which earns more long term.
Read postUp to four units on most single-family lots. What the rules allow.
Read postWhen you need a permit, what they cost, and how long they take.
Read postService area
SSMUH rules apply across British Columbia, but each Mission area has its own setbacks, parking minimums, and lot-coverage limits, plus riparian and ALR overlays in places. A coach house near Hatzic Lake differs from a basement suite in the heritage core. See the area page closest to your home for what we typically run into there.
Chilliwack neighborhoods
See also the full Chilliwack rollup.
Fraser Valley cities
See the full service area map.
Kitchen renovations by city
Dedicated kitchen pages for each Fraser Valley city we work in.
Bathroom renovations by city
Dedicated bathroom pages for each Fraser Valley city we work in.
Basement renovations by city
Dedicated basement & legal suite pages for each Fraser Valley city we work in.
Whole-home renovations by city
Dedicated whole-home renovation pages for each Fraser Valley city we work in.
Legal suites & additions by city
Legal secondary suites, coach houses, and home additions by Fraser Valley city.
Zoning & feasibility first
We come to your property, look at the structural feasibility and the zoning, and talk honestly about what is possible. Legal suite, coach house, above-garage unit, or addition. Site visit, clear scope, and a line-item quote. No pressure, no mystery pricing.