From The Workshop

What Questions Should I Ask a Deck Contractor in Sydney?

By Greg Weinbren · 12 min read · May 2026

Most homeowners ask the wrong questions. They ask about price first, timeline second, materials third. Those matter — but they’re the questions every contractor is ready for, with answers polished to close the sale. The questions that actually separate a reliable builder from a risky one are the ones contractors rarely get asked. After 500+ decks across Sydney and twelve years of quoting jobs, I can tell you which questions surface the truth and which ones get a smooth deflection.

This guide gives you the five deep-dive questions worth asking every contractor on your shortlist, then a quick-fire list covering frame specs, people, paperwork and timeline. Use them all. The answers will tell you everything.

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Why the Questions Matter More Than the Answers

Before the list — a quick word on what you’re really doing when you ask these. You’re not running a quiz. You’re watching how the contractor handles being asked. A reliable builder will welcome specific questions because they’ve got specific answers. An unreliable one will get vague, defensive, or change the subject.

Pay attention to:

• Specificity. Real builders answer with numbers, names, dates. Bad ones answer with “we usually” and “around about”.
• Comfort. A builder who’s been doing this a long time enjoys these conversations. Pushback or impatience tells you what working with them will feel like.
• Consistency. Ask the same question two ways across two meetings. The answers should match.

Now the five questions worth the full conversation. If you haven’t shortlisted candidates yet, start with my guide on how to vet the shortlist first — these questions work best on a pre-vetted shortlist.

The Five Deep-Dive Questions

1. “Walk Me Through Your Framing Spec — Bearer Size, Joist Centres, and Fixings.”

This is the single most diagnostic question you can ask, and most homeowners never ask it. The frame is what your deck stands on for the next twenty years. It’s the bit nobody sees once the boards go down, which is exactly why corner-cutting hides there.

A specialist deck builder will answer something like: “For a standard residential deck with 90×19 hardwood boards, I’ll typically run 140×45 H3 treated pine MGP10 joists at 450mm centres, on 190×45 bearers at 1.8m centres, with H4 treated pine posts to AS 1684. I tape the joists, I bolt the ledger with Z-flashing into the wall plate, and I’m using stainless or galvanised fixings rated for the proximity to salt air.”

A generalist or shortcut builder will answer: “Yeah, we use treated pine, standard sizes, comes out really strong.”

The difference isn’t memorisation. It’s whether the builder thinks about framing as engineering or as filler. AS 1684 is the Australian Standard covering residential timber framing, including deck bearer and joist sizing. Any builder doing real decking work knows it by feel.

Listen for: timber grade (H3 vs H4 — H4 if in ground contact or wet zones), joist centres (450mm for hardwood, 300–400mm for composite depending on board), fixing type (galvanised minimum, stainless near the coast), and joist tape (a thin self-adhesive strip across the top of each joist that prevents water sitting in screw holes and rotting the timber).

2. “Who Exactly Will Be On Site Building My Deck — and Who Made the Decisions on the Quote?”

This question flushes out the gap between the person selling you the deck and the people building it. On a lot of jobs, those aren’t the same people — and that’s where quality drops.

You want to hear that the person quoting you is the person carpentering. If they’re not, you want clear answers about who is, how long they’ve worked together, and whether they’re employees or subcontractors. Subcontractors aren’t always bad — but you have a right to know.

Look at:

• Is the person in front of you actually swinging the hammer?
• If there’s a crew, is it the same crew every time, or does it change job to job?
• Who will I contact on site each day with questions?
• If something goes wrong on day forty, who’s responsible — the sales rep, the crew, or the company?

The answer reveals the business model. A specialist owner-operator builds a different kind of deck than a sales-led outfit that subs out the work. Neither is automatically better — but you should know which one you’re hiring.

3. “What Does Your Standard Warranty Cover, and What’s Excluded?”

Every builder mentions “warranty” on the first call. Very few will read you the actual terms. Ask.

The strongest warranties cover structural defects (frame failures, bearer/joist issues, fixing failures) for the longest period — typically seven to ten years on the structure, two years on the workmanship and finish. The weakest are vague verbal promises with no document behind them.

What to listen for:

• Is the warranty in writing, signed, with a duration on the structure and a separate duration on the boards/finish?
• What voids it? (Some warranties void if you don’t oil the deck on a schedule. Fair enough. Just know it.)
• Who honours it if the builder retires, closes the business, or moves states?
• Are you also covered by the NSW Home Building Compensation Fund (required on residential work over $20,000) for the worst-case scenario where the builder is no longer trading? (Verify current threshold before relying on it.)

A real builder will hand you a one-page warranty summary on request. A reluctant one will say “she’ll be right”.

4. “Can I Visit a Job You’ve Got Running This Week, or One You Finished in the Last Month?”

Photos are easy to fake. Job sites aren’t.

This single request will tell you more in twenty minutes than two hours of phone calls. You see the standard of work in progress. You see how the site is kept (tidy site = tidy frame underneath). You see how the builder talks to a real client. You can ask the homeowner what they think — and most are happy to tell you.

The question also separates people fast. Builders with current work and recent handovers say yes immediately. Builders without say “we’re between jobs” or “the client’s privacy” or “I’ll send you photos instead”. Sometimes those answers are genuine. More often they’re a tell.

If the builder takes you to a site, watch what you see, not what you’re told. Are the offcuts stacked or scattered? Are the joists actually at the spacing claimed in question 1? Does the homeowner mention any problems they’ve had?

5. “What’s Your Start Date in Writing, and What Happens If You Miss It?”

The most common dispute in residential building isn’t quality — it’s timing. Start dates slip. Projects overrun. Materials don’t show up. The question is what your builder does when it happens. For a realistic sense of how long a real Sydney deck build takes from quote to handover, see my breakdown on how long a deck build actually takes.

The reliable builder commits a start date in writing in the contract, names the typical duration, and tells you upfront what kinds of delays they take responsibility for (their crew availability, their material ordering) versus what they don’t (council inspection delays, weather past a defined threshold, owner-driven scope changes).

What you don’t want to hear: “We’ll fit you in once we finish the current job” with no firm date, or “These things take as long as they take” with a shrug.

A start date you can’t pin down is a finish date you can’t trust either.

The follow-up question matters too: what’s the penalty if they don’t start on time? Most decking contracts don’t have a penalty clause and that’s industry standard — but the conversation about what happens reveals how the builder thinks about their obligations. A pro will explain how they’d compensate you (e.g. credit on the final invoice, expedited completion). A cowboy will get defensive.

Quick-Fire Question List

The five above are your deep dives. The list below covers the remaining gaps. Don’t ask all of these in one conversation — you’ll come across like an inquisitor. Pick the ones that matter to your project.

Frame and Structural

• What treatment level on the framing timber — H3 or H4?
• What’s your joist spacing for the board you’ve quoted?
• Are you taping the joists before the boards go down?
• How are you flashing the ledger where the deck meets the house?
• What fixings — galvanised or stainless? (Stainless if you’re within a kilometre or two of the coast.)
• What’s the deck height above ground, and what footing system are you using?

People and Accountability

• How long have you been trading under this business name?
• What’s your NSW Builder’s Licence number? (Verify on the Service NSW licence register — that’s the official check.)
• Do you carry current public liability insurance? Can I see the certificate?
• Will I be covered by the NSW Home Building Compensation Fund for this job? (Required on residential work over $20,000 — verify current threshold.)
• Are you using subcontractors for any part of the build?
• Who is my first point of contact day-to-day during the build?

Paperwork and Money

• Is everything in a written contract before any work starts? (NSW requires a written contract on residential work over $5,000 — verify current threshold.)
• What’s your deposit? (NSW caps residential building deposits at 10% — verify current cap.)
• What’s the payment schedule across the build — milestones or weekly?
• Final payment timing — on completion or after defects period?
• What happens to my deposit if I cancel before work starts?
• Do you provide a tax invoice and is GST included or added?

For context on whether the dollar figure on the quote itself is realistic, see my guide on how much a Sydney deck contractor should actually cost.

Timeline and Process

• When can you start, in writing?
• How long from start to finish for a deck this size?
• Will you be on site every day, or rotating across multiple jobs?
• What’s your wet weather policy?
• What council approvals are needed and who lodges them?
• What happens if I want to change something mid-build?

After the Build

• What’s your written warranty on the structure and on the finish?
• Who do I call if something needs adjusting in year one?
• Do you offer an annual check-in or oiling service?
• What do you recommend for ongoing maintenance — and how often?

Red-Flag Answers to Walk Away From

The questions above flush out information. Some of the answers, if you hear them, should end the conversation. These are the deal-breakers:

• “Cash only and I’ll knock the GST off.” — No warranty, no insurance cover, no recourse, illegal under NSW law.
• “I don’t usually do written contracts on jobs this size.” — Required by law on residential work over $5,000 (verify current threshold).
• “Deposit’s 25%.” — Above the NSW 10% cap (verify current cap).
• “Trust me, mate, I’ve been doing this for years.” — In response to specific technical questions about framing. Trust isn’t a substitute for specification.
• “We can start Monday if you sign tonight.” — Reliable builders are usually booked weeks or months ahead. Same-day availability is either a quiet patch (possible) or a sales tactic (likely).
• “We’ll figure out the details as we go.” — Decks need a spec before the saw comes out. “We’ll figure it out” means you’ll pay for changes you didn’t agree to.

How to Use This List in Practice

Three meetings, three sets of questions:

1. First call or site visit: Five deep-dive questions. Focus on framing spec and site visit request.
2. After the quote arrives: Quick-fire questions on paperwork and money. Match what’s in writing against what was said.
3. Before signing: Final pass on timeline, accountability, warranty. Anything still vague gets clarified or the deal doesn’t close.

If you’ve used the full list with two or three contractors, you’ll have more information than 95% of homeowners. The right builder will stand out. The wrong one will already have disqualified themselves.

Where The Decksmith Sits in This

I’m Greg Weinbren — lead carpenter on every build. NSW Builder’s Licence 272840C, verifiable on the public register. Twelve years specialising in decks, pergolas, balustrades, pool surrounds, stairs and the structures that go with them. Eastern Suburbs base, Sydney-wide work.

I welcome every question on this list. The framing spec question is one of my favourite parts of a first meeting because it’s where I get to talk about the part of the job nobody else thinks matters. The site visit question is yes by default — there’s almost always a current build or recent handover within a few suburbs of where you live.

If you want a rough idea of where your project might sit on cost before we even speak, the pricing calculator at the-decksmith-pricing-guide.netlify.app will give you a realistic range based on your specs.

Either way: ask the questions. Ask all of them. The right builder will thank you for it. If you’re still deciding whether to hire a contractor at all, my guide on DIY vs hiring a deck contractor covers where that line sits.