Shed kits vs full build — an honest comparison.

Option A — kit supply only.

• BlueScope C-section steel cut to length, pre-drilled
• Colorbond cladding (roof + walls) cut to length
• Fasteners, brackets, base plates, ridge caps
• One motorised roller door assembly
• Gutters and downpipes
• AS 1170 wind-load engineering certificate
• Assembly drawings
• Delivered to your block on a tilt-tray

Kit price (typical 6×9m three-car garage): $6,500–$8,000.

You still need on your account: slab (~$5–$7K), erection crew (~$3–$5K), building permit ($600 council + $1,400–$2,000 private surveyor), services rough-in if any.

Option B — full supply-and-install.

• Everything in Option A
• Engineered slab to AS 2870 (footings sized to soil class)
• City of Casey building permit lodged + paid
• Private building surveyor booked + paid
• Full steel erection by our crew
• All sheeting, flashings, gutters and downpipes installed
• Roller doors fitted and tested
• PA side door fitted, weatherstripped
• Three-phase or single-phase electrical rough-in to nominated location
• Final inspection coordination + occupancy / certificate of final
• BlueScope warranty registered, our 7-year structural warranty written

Full-build price (same 6×9m three-car garage): $18,000–$25,000 turnkey.

Honest comparison — the math.

Option A (kit) total project cost when you add the trades on your own: $6,500 kit + $6,000 slab + $4,000 erection + $1,800 permit and surveyor = ~$18,300. Plus 2–3 weekends of your time managing it. Plus the risk on the items where DIY-erection goes wrong (square frame, correct bracing, sheeting lap direction, flashing details).

Option B (full build) on the same job: $18,000–$25,000. The kit-route saving evaporates entirely once the slab, erection and permit are individually quoted — sometimes you actually pay more on kit-route because each trade marks up retail. Where the kit genuinely wins: you have an experienced erection crew you can call in for $0 (mates), the slab concreter is a known low-cost contractor, and you can stage payment differently across trades.

When kit-only IS the right call.

• You are a confident DIY builder with steel-erection experience
• You have a help crew lined up for free
• Your block is flat with vehicle access (no crane required)
• The shed is small (6×6m or under), single-storey, no mezzanine
• You already have an engineered slab on the block or are pouring one for another reason
• You’re comfortable lodging your own permit and managing the surveyor

When full-build is the right call.

• Shed is over 6×9m or has more than one roller door
• Wall height over 3.0m (erection without a scissor lift is dangerous)
• Block is sloped, soft, or has restricted access
• You want one fixed price and one warranty — no chasing four trades
• You have an insurance / bank loan condition requiring registered-builder construction
• The shed is industrial or commercial occupancy (Class 7b or 8)

Hybrid — often the sweet spot.

We supply the kit, the slab, the permit, the engineering certificate and the surveyor; you handle the steel erection with mates over a weekend; we come back to flash the apex, fit the roller doors, run the gutters and book the final inspection. Saves you the $3,000–$5,000 erection labour while we still own the parts that go wrong most often (slab dimensions, flashings, final certification). Quoted line-by-line so you can split where you like.

Top six DIY-erection failures we’ve been called in to fix.

1. Slab dimensions off the engineering — base plates don’t line up with bolts
2. Frame out of square — every sheet fights the next, gaps everywhere
3. Purlins installed upside-down or backwards — sheeting laps fail in the first storm
4. No bracing in open-front sheds — frame racks in the first 60 km/h gust
5. Wrong screw pattern on Colorbond — leaks within months
6. No apex or gable flashings — water runs inside down the column webs