How to Choose a Deck Builder in Melbourne: 7 Questions to Ask Before You Sign

Are you fully insured — and what does that cover?

Before you ask about materials, timeline, or price — ask about insurance. Not because you're expecting something to go wrong, but because the answer tells you immediately whether you're dealing with a professional operation or a cash-in-hand operator who disappears when problems emerge.

Public liability insurance is what protects you if the builder causes damage to your property during the build — a cracked window, damaged paving, a broken fence. The standard minimum for a quality builder is $5 million. The better ones carry $10 million. You should also ask about workers compensation: if an employee or subcontractor is injured on your property during the build, workers comp is what ensures you're not left exposed.

Ask to see the certificate of currency — a document your insurer provides that shows the policy is active, what it covers, and when it expires. A builder who carries proper insurance will hand this over without hesitation. One who stalls or gives vague reassurances is telling you something important.

What materials do you recommend, and why?

This question isn't about getting a right or wrong answer on decking products — it's about finding out how the builder thinks about materials. A competent builder has opinions grounded in experience. They know why certain composite boards perform better in Melbourne's UV conditions than others. They understand the difference between Class 1 hardwood and cheap treated pine. They've seen what happens to materials that weren't suited to the site they were specified for.

A good materials conversation should cover: the decking boards (composite vs hardwood, which product and why), the subframe (what's being used for bearers and joists, what treatment level for ground contact), and the fixings (concealed clip systems vs face screws, and why one or the other suits this project).

What's included in the quote — in writing?

A quote is not a contract. But the level of detail in a quote tells you a lot about whether a builder is building the same thing in their head that you are.

A detailed quote should specify: the deck area in square metres, the brand and product name of the decking boards, the subframe specifications (member sizes, treatment class, footing type and depth), what's included (fascia boards, picture frame border, decking oil, rubbish removal) and what's explicitly not included (stairs, balustrades, drainage works). Any provisional sums — items where the final cost depends on site conditions — should be itemised separately and explained.

The classic catch: a quote that lists "deck construction" as a single line item at a very competitive rate. That quote is almost always missing something — usually footings, drainage, or the fact that the "deck" doesn't include fascia, balustrade, or stairs that you assumed were part of the build.

How do you handle drainage under and around the deck?

This is the question that most separates experienced deck builders from people who can swing a hammer. Drainage is invisible once the deck is built — and it's responsible for a disproportionate share of deck failures, structural problems, and unhappy homeowners five years down the track.

Under a deck, water that can't escape creates conditions for fungal decay in timber framing, corrosion in fixings and joist hangers, and soil movement under footings. Around a deck, poor grading or the absence of storm water planning can direct water toward the house — a problem that gets far more expensive than the deck ever cost.

A builder who thinks about drainage has answers ready: where will surface water run off the deck boards? What happens to water that penetrates between the boards? Is there an existing stormwater point nearby, and does it need to be connected or extended? Does the slope of the block require any groundwork to protect the footings?

Can I speak with a past client about their experience?

Google reviews are useful but limited. They're typically written immediately after completion, when enthusiasm is highest and problems haven't had time to appear. A reference call with a client from 12–18 months ago tells you something different: whether the deck has held up, whether the builder was responsive when a small issue came up, and whether the client would use them again.

A confident builder with a portfolio of good work will have no hesitation offering references. They may not always be able to find a client willing to take calls — some people are private about their home — but the willingness to try, and the ability to point to a list of completed work with real suburb names and project types, is itself a meaningful signal.

Who actually builds it — you, or subcontractors?

There's nothing inherently wrong with a builder who uses subcontractors — many reputable builders do. The question is about accountability and quality control. When a deck builder subcontracts the work to a different crew, the builder needs to be on site enough to supervise, check the work, and own the outcome when something doesn't meet standard.

The risk is the builder who wins work on the strength of their own presentation and work history, then hands the job to a crew they've never used before — or a crew who's cheaper because they cut corners. This happens more often than homeowners realise, and it's one reason why a quote from a well-presented builder sometimes produces a disappointing result.

Ask directly: will you be on site during the build? If you use trades, how do you manage their quality? What happens if the work doesn't meet your standard?

What happens if something goes wrong?

This isn't a pessimistic question — it's a practical one. Builds have variables: weather delays, a supplier substitutes a component, a ground condition that wasn't visible until the first footing was dug. How a builder handles the unexpected tells you more about the experience you're going to have than anything that goes according to plan.

Specifically, you want to know: what's your warranty on workmanship, and what does it cover? If a board lifts or a fixing fails in the first two years, what's the process? Are you contactable after the job is done — or do you become unreachable once the final invoice is paid?

In Victoria, domestic building contracts for work over $10,000 must include Domestic Building Insurance (DBI), which provides coverage for defects if the builder dies, disappears, or becomes insolvent. If the quote is over $10,000, check that DBI is included. Many builders don't mention it unless asked.