Choosing the wrong builder is the most expensive mistake you can make on a garden suite. Unlike a kitchen or bathroom renovation, a garden suite is a ground-up detached dwelling: it needs a zoning analysis, permit drawings, an engineered foundation, trenched servicing, and a full Building Code inspection cycle. Plenty of good renovation contractors have never taken a detached suite through that process — and your backyard should not be where they learn.
This guide is based on 15+ years of construction experience and the garden suite projects we deliver across Toronto and the GTA. Use it to evaluate any builder — including us.
Why Hiring for a Garden Suite Is Different
Three things separate a garden suite from a typical renovation. First, the permit burden is heavier: the project lives or dies on a compliant design — setbacks, angular planes, the 60 m² limit, tree protection, and the emergency access path all have to be resolved on paper before anything is built. A builder without real permit experience will cost you months.
Second, the below-ground work is unforgiving. Foundations, drainage, and servicing trenched from the main house are where budgets blow up when they are underscoped — and where quotes that look cheap turn out to have simply left things out.
Third, coordination risk is concentrated. Designer, engineer, arborist, utility locates, excavation, and construction trades all have to hand off cleanly. This is why the design-build model — one team, one contract, one all-in price — fits garden suites so well, and why we structured our own service that way.
The Essential Garden Suite Builder Checklist
Before hiring any builder for a detached suite in Ontario, verify that they meet all of the following:
Licensed, Registered Business
A registered business entity with a valid HST number and any municipal licences their trade work requires. Ask for the business number and verify it. A builder operating informally is a risk you cannot paper over with a good price.
Liability Insurance ($2M+ Coverage)
Commercial general liability insurance with at least $2 million in coverage, confirmed directly with the insurer. A garden suite build involves excavation next to your home and your neighbours' property — this is not optional.
WSIB Clearance Certificate
A current WSIB clearance certificate proves the builder's workers are covered for workplace injuries. Without it, liability for an injury on your property can land on you. Verify the certificate on the WSIB website.
Real Detached-Suite Permit Experience
Ask specifically: how many garden or laneway suites have you taken from feasibility through permits to occupancy? Renovation experience does not transfer automatically. A builder who can show approved permit sets and finished suites has proven the exact skill your project needs.
Feasibility Before Design
A professional starts with a zoning and site review — envelope, trees, access path, servicing — before selling you a design. A builder who quotes a garden suite without seeing your lot, or who skips straight to floor plans, is guessing with your money.
All-In, Written Pricing
The quote should state clearly that design, permits, servicing connections, foundation, construction, and finishes are included — and itemize anything excluded. Construction-only quotes are the most common source of five-figure surprises on suite projects.
Written Workmanship Warranty
A written warranty of at least 1 to 2 years on workmanship, separate from manufacturer warranties, with claim terms spelled out in the contract. A builder who stands behind a whole dwelling in writing is a builder who plans to still be around.
Verifiable References & Completed Suites
Ask for references from past garden suite clients specifically, and follow up: was the permit approved smoothly, did the price hold, was the timeline honest, would they hire the builder again? Review the portfolio of finished suites — ours is at /our-work.
Red Flags to Watch For
Any one of these is a reason to keep looking:
Quotes a firm price without a site visit
Garden suite cost depends on access, servicing distance, grading, and trees — none of which can be assessed from the street view. A confident number produced sight-unseen is a number designed to change later.
Suggests building without a permit or 'as a shed first'
An unpermitted dwelling cannot legally be occupied or rented, creates insurance and resale problems, and can be ordered removed. Any builder proposing to dodge permits is proposing to transfer the risk to you.
A price dramatically below other quotes
On detached suites, lowball quotes almost always exclude scope — design fees, permit costs, servicing trenches, sometimes the foundation itself. Compare what is included, not just the bottom line.
Cannot show a completed garden or laneway suite
General renovation photos are not evidence of detached-suite competence. If the builder cannot show you an approved permit set and a finished, occupied suite, you would be their pilot project.
Demands a large upfront payment
Milestone-based payments are the industry standard. A builder who needs a big cheque before mobilizing is either underfinanced or planning to be paid ahead of the work — both are your problem eventually.
Cannot provide proof of insurance or WSIB
Hesitation, excuses, or 'we don't need that' on insurance and WSIB is disqualifying in Ontario, full stop.
Hand-waves servicing and trees
'We'll sort out the hydro later' and 'that tree won't be an issue' are the two sentences that precede the most expensive garden suite surprises. Both must be resolved during feasibility, on paper.
Poor communication during the quoting stage
Slow replies, missed appointments, and vague answers before you sign only get worse after the deposit clears. Quoting-stage communication is a preview of the project.
Questions to Ask Before You Hire
The consultation is your interview. These questions separate builders who know garden suites from builders who want to find out on your dime:
How many garden or laneway suites have you taken through permits?
Do you run a feasibility and zoning review before design?
Is your price all-in? What exactly is excluded?
Who prepares the architectural and structural drawings?
How do you handle tree protection and the access path rules?
How is servicing (water, sewer, hydro) scoped and priced?
Can you provide your WSIB clearance and insurance certificates?
What is your payment schedule, milestone by milestone?
What workmanship warranty do you offer, in writing?
Who is my single point of contact during the build?
Can I speak to past garden suite clients?
What happens if the City requests drawing revisions?
Comparing Garden Suite Quotes Properly
Get two or three quotes, but compare them on scope, not just totals. For garden suites specifically:
- Demand the same basis: same suite size, storeys, and finish level, priced against your actual lot after a site visit.
- Check the all-in line items: design and engineering, permit fees, survey, arborist work if needed, servicing trenches and connections, foundation, construction, and finishes. Anything missing from one quote explains its lower price.
- Look at timeline honesty: permits take 2–4 months and custom construction 4–6 months. A builder promising dramatically faster is either exceptional or optimistic — ask which, and ask for evidence.
- Weigh the delivery model: a design-build quote covers one accountable contract; a construction-only quote leaves you hiring and coordinating design and permits separately. Price the whole journey, not one leg of it.
Rule of thumb: on a project of this size, the cheapest quote is almost never the cheapest project. The builder who found $60,000 of “savings” on paper usually finds them again on site — as extras. Our garden suite cost guide shows what realistic all-in pricing looks like, so you can spot a quote that is missing pieces.
What Your Garden Suite Contract Should Include
A garden suite contract governs a year of work and hundreds of thousands of dollars. Before signing, make sure it includes:
- Full scope of work: feasibility, design, permit application, servicing, construction, and finishes — itemized, with exclusions stated explicitly.
- All-in fixed price and payment schedule: milestone-based payments tied to permit issuance, foundation, framing, lock-up, and completion, with the final payment after your walkthrough.
- Materials and specifications: finish levels, brands, and allowances stated realistically, not as placeholders.
- Timeline with stages: design, permit, and construction phases with expected durations, and how delays are communicated.
- Change order process: changes priced and approved in writing before extra work proceeds.
- Warranty terms: the written workmanship warranty, its duration, coverage, and claim process.
- Insurance and WSIB references: policy numbers, with coverage maintained for the project's duration.
- Site protocols: tree protection measures, neighbour notice, working hours, site cleanliness, and debris removal.
- Dispute resolution and cancellation terms: how disagreements are handled and on what terms either party can exit.
Hold Us to This Checklist
Home Garden Suites is licensed, insured, and WSIB-cleared, with 15+ years of construction experience, design-build delivery under one contract, all-in pricing, and a 2-year written workmanship warranty. Garden suites are not a sideline for us — they are the whole business. Ask us every question on this page.
