How much bench run you need: 4.2m to 5.4m for 10 people.
For a Casey family who cook outside most weekends and host 10 to 12 people a few times a year: 4.2 to 5.4 lineal metres of bench at 600mm deep, under 24 to 34 m² of roofed alfresco, with 75 to 85 MJ/h of gas capacity. That is about $26,000 to $46,000 built in 2026. If you only ever host 4 to 6, drop to 3.0 to 3.6 metres of run under 16 to 20 m² and around 40 MJ/h, and save roughly $12,000. Size it below, then price it.
Size the job first, then see what it costs.
Drag the two sliders to the quantities you need. The estimator shows the bench run in lineal metres, the roofed area in square metres, the gas load your appliance choice draws, and roughly how many people can sit at a table in what is left over. Set the roof slider to 0 if you are building under a roof you already have.
- Bench run is priced at $1,700 to $2,700 per lineal metre for cabinetry, benchtop and installation at 600mm deep, which is a mid specification.
- Roofed area is priced at $580 to $900 per square metre for a Colorbond alfresco on bored piers, tied into the existing house roof.
- Appliance figures are supply and install for mid-range built-in units. Premium appliances can add $2,000 to $6,000 on top.
- Excludes decking, landscaping, retaining, pool works and any asbestos removal.
- This is a 2026 guide, not a quote. A fixed price needs a measure and a look at your gas meter and switchboard.
How to measure it properly with a tape and a phone.
Ten minutes in the backyard gets you numbers accurate enough for a real conversation. Do these six things and email them to any builder and you will get a genuine ballpark without waiting for a visit.
- The wall length you can actually use. Stand at the back door and measure along the house wall between the two things you cannot move: usually a window at one end and a downpipe, meter box or corner at the other. That is your maximum straight run.
- The depth you can build to. Measure from the house wall out to the point you would not want to build past: the edge of the existing slab, the clothesline, or the boundary setback. Anything under 4.2 metres and you are choosing between a kitchen run and a table.
- The narrowest point of your side access. Not the gate. The narrowest point, which is usually where the meter box or an air conditioner sits. Write it down in millimetres.
- The height from the slab to the underside of the eave. This sets the roof pitch and tells us whether a bar wall will block a window. Also measure to the bottom of any window on that wall.
- Four photos. The gas meter with the data plate readable, the switchboard with the door open, the wall where the roof would tie in taken from far enough back to include the gutter, and the whole yard from the back fence looking at the house.
- The number of people, twice. How many you cook for on a normal Sunday, and how many at the biggest gathering you host in a year. Those two numbers, not the second one alone, are what should set the size.
If you would rather we did it, the site visit is free and takes about an hour. Either way, book it through the quote form or ring (03) 9003 0108.
Add up what actually has to fit, then add the allowances.
An outdoor kitchen is a row of modules. Work out which ones you need, add their widths, then apply the two allowances at the bottom. That is the whole method, and it beats guessing at a round number every time.
| Module | Width you must allow | Notes |
|---|---|---|
| 4-burner built-in BBQ head | 850 to 900mm | Confirm against the exact model. Cut-outs vary by 30mm between brands. |
| 6-burner built-in BBQ head | 1,150 to 1,250mm | The most common module people underestimate. |
| Side burner | 350 to 400mm | Worth it if you make sauces or boil seafood outside. |
| Landing bench, hot side of the BBQ | 300mm minimum | Somewhere to put a hot tray down. Non-negotiable. |
| Prep bench | 900mm minimum, 1,200mm for two cooks | The single most valuable metre in the whole run. |
| Single bowl sink module | 600mm plus 300mm drain side | Needs hot and cold, waste to sewer and a plumbing certificate. |
| Outdoor-rated bar fridge | 600mm | Must be an outdoor-rated unit. An indoor fridge in an alfresco fails in 2 summers. |
| Kegerator | 700 to 900mm | Check the door swing against the corner before you commit. |
| Bin pull-out | 450mm | Everyone forgets it and everyone wants it. |
| Built-in pizza oven | 1,000 to 1,400mm plus 300mm each side | Clearances are set by the oven manufacturer and the flue standard, not by taste. |
| Allowance: end panels, scribes and joins | Add 10 percent | Applies to every run. |
| Allowance: dead corner on an L-shape | Add 600mm | The inside corner of an L is essentially unusable bench. |
Heights and clearances: bench 900 to 920mm, raised bar ledge 1,050mm, bar overhang 300mm deep with 600mm of width per stool and 700 to 750mm clear behind it, and 1,100mm of clear circulation behind the cook, 1,200mm if people walk past while someone is cooking.
Send us your four photos and three numbers.
Wall length, usable depth and narrowest side access, plus photos of the meter, switchboard, wall and yard. We will come back with a real size and a real range, usually the same day.
Rules of thumb, wastage and the safety margins.
Material wastage.
- Stone and porcelain slab: add 10 to 15 percent to the area for cuts, cut-outs and edge build-ups. Always keep one offcut in the shed. A matching repair in 5 years is nearly impossible once the batch is gone.
- Tile: add 10 percent. More like 15 percent for a patterned or rectified tile that has to line through.
- Concrete volume: add 5 to 8 percent. Formwork is never perfectly true and the sub-base is never perfectly flat.
- Timber: add 12 percent for defects, docking and end splits.
- Bench run: add 10 percent to your module total before you decide on a number.
Gas capacity, and the margin that matters.
Total your appliances: a 4-burner built-in is about 36 to 48 MJ/h, a 6-burner 60 to 70, a side burner 12 to 15, a gas pizza oven 25 to 40 and each patio heater 12 to 18. A full outdoor kitchen usually lands around 75 to 85 MJ/h. That is not the whole question though. It has to be added to what the house already draws: a ducted heater is roughly 110 to 160 MJ/h, a cooktop 40 to 55, and a continuous flow hot water unit 100 to 160. A licensed gasfitter runs a load calculation under the Australian gas installation standard, and if the total exceeds what your meter and regulator can deliver, the distributor has to upsize them. That is an application with a lead time of a few weeks, so it needs to be found at the quote stage, not on installation day.
The second half of that calculation is the run length. Pipe diameter is sized to the load and to the distance, and a 20mm line will simply not carry 79 MJ/h over 25 metres at the required pressure. If your meter is on the far side of the house, that changes the price and it changes the trench. Ask for the load calculation to be shown to you. Any gasfitter worth using will have it on paper. More on the gas side on our BBQ installations page.
Electrical capacity.
Lights and fans are trivial: an LED downlight is 6 to 10 W and a ceiling fan 60 to 75 W. Fridges are small too, at roughly 0.6 to 1.0 A for a bar fridge and about 1.5 A for a kegerator. Heaters are the problem. Each 2.4 kW strip heater is 10 A, so a pair of them is 20 A and needs its own circuit from the switchboard. Hanging two heaters off an existing garden or shed circuit is why people trip the RCD every cold night in July. Budget $880 to $2,400 for a proper dedicated outdoor circuit and have it run while the slab is open.
Sizing the run to the space instead of to the appliances.
This is the one that costs the most and it happens on jobs across Casey every month. Someone measures the wall, decides on a 4.5 metre run because that is what fits, and then buys the appliances afterwards. The 6-burner head turns out to be 1,220mm rather than the 1,100mm they assumed, the fridge is 620mm rather than 600, and suddenly the BBQ hood fouls a post when you lift it and the fridge door hits the return of the L. Fixing that after the cabinetry has been fabricated is $900 to $2,400 and about 3 weeks, because the carcass is made to the cut-out.
The fix takes an hour. Get the exact model numbers, get the cut-out dimensions from the manufacturer specification sheet rather than from the retail listing, and chalk the whole run out full size on your slab or your lawn. Stand at the chalk BBQ and mime opening the hood. Walk behind where the cook will stand. You will find the problem in the first two minutes and it will cost you nothing.
The two runners-up.
- Undersizing the depth. On a 400 to 520 m² Cranbourne East or Clyde North block the setback usually takes the depth, not the width. A 3.0 metre deep alfresco with a 600mm bench leaves 2.4 metres, which is fine until you put a table in it. Decide early whether the kitchen goes on the back wall (which needs depth) or the side wall (which can be long and shallow). The permits page covers how setbacks and easements shape this.
- Ignoring the gas load until installation day. Discovering on the day that the meter cannot deliver 80 MJ/h stops the job for the weeks it takes the distributor to upsize the meter and regulator. It is a 10 minute check at the quote stage.
A real Cranbourne East house, with the numbers added up.
A 2019 four-bedroom build on a 448 m² block, Class M clay, with a builder-supplied alfresco slab of 3.6m by 4.2m under the main roof. Family of four, cook outside most weekends, host 10 to 12 at Christmas and a couple of times over summer. They want a 6-burner, a side burner, a sink and a bar fridge.
Step 1: add the modules.
- 6-burner built-in head: 1,200mm
- Side burner: 400mm
- Landing bench, hot side: 300mm
- Prep bench: 900mm
- Sink module plus drain side: 900mm
- Bar fridge: 600mm
- Subtotal: 4,300mm
- Add 10 percent for end panels and scribes: 4,730mm
- Add 600mm for the L-shape dead corner: 5,330mm, call it 5.3 lineal metres
Arranged as 3.4 metres along the back wall with a 1.9 metre return, which keeps the cook facing the yard rather than the wall.
Step 2: check the roofed area.
- Existing alfresco: 3.6 x 4.2 = 15.1 m²
- Kitchen strip needs 5.3 x 1.7 = 9.0 m² of that
- Leaves 6.1 m², which seats 3 people. Not enough.
- Extend the roof out 1.4 metres and across to 5.0m: 5.6 x 5.0 = 28.0 m²
- Now 28.0 minus 9.0 = 19.0 m² for the table, which seats 9 comfortably
- New roofed area to build: 28.0 minus 15.1 = 12.9 m²
Step 3: check the gas.
6-burner at 65 MJ/h plus side burner at 14 MJ/h equals 79 MJ/h of new load. The house has a ducted heater, a cooktop and a continuous flow hot water unit. The gasfitter does the load calculation at the site visit, photographs the meter data plate, and confirms whether the existing meter and regulator carry it. On this house they did, and the run from the meter was 14 metres in 25mm.
Step 4: add it up.
- Cabinetry and benchtop, 5.3 lin m at $1,700 to $2,700: $9,010 to $14,310
- Appliances: 6-burner, side burner, sink and tapware, bar fridge: $4,000 to $6,900
- Gas run, load calculation and compliance certificate: $900 to $2,400
- Outdoor sub-circuit, RCD, 4 downlights and 2 GPOs: $880 to $2,400
- Hot and cold to the sink, waste to sewer, plumbing certificate: $1,200 to $2,800
- Roof extension, 12.9 m² at $580 to $900 including the tie-in: $7,480 to $11,610
- Permit, soil report and engineering: $580 to $1,800
- Total: about $24,100 to $42,300
Put 5.3 and 13 into the two sliders above, choose the third appliance package, tick the first four extras and you will get the same answer, because that is exactly what the estimator is doing. What it costs overall, tier by tier, is on the budget page, the material choice is on the benchtop page, and the full itemised rate card is on the pricing guide.
Most people need less than they think.
We will happily build you 7 metres of bench, but here is what we notice going back to jobs a couple of years later. The prep bench and the landing bench get used every single time. The sixth burner gets used at Christmas. The kegerator gets used for the first summer and then becomes a fridge. The pizza oven is either the best thing in the yard or an expensive ornament, and which one it turns out to be depends entirely on whether you already cook pizza indoors.
- Size for the Sunday you host 40 times a year, not the Christmas you host once. Hire a trestle table for the once.
- A 3.0 to 3.6 metre run does about 90 percent of what a 5.3 metre run does for a family of four, and it saves roughly $4,000 to $9,000.
- If you cook outside 4 or 5 times a year, a good freestanding BBQ under an existing eave at about $2,500 is the right answer and we will tell you so.
- Buy the prep bench before the second appliance. If the budget only stretches to one more metre, make it bench, not another burner.
There is one thing we will not do on size grounds: we do not build commercial-scale fit-outs with commercial refrigeration and extraction. That is a different trade with different standards. Everything up to a large domestic entertainer, across Cranbourne, Berwick, Narre Warren, Hampton Park and Endeavour Hills, is what we do. Once it is built, the lifespan guide and the warranty page cover what happens next, and the build guide covers what happens in between.
Sizing questions.
How many metres of bench does an outdoor kitchen need?
How big does the alfresco need to be for a kitchen and a table?
How much gas does a built-in outdoor kitchen use?
What is the most expensive sizing mistake people make?
How much waste should I allow when ordering stone or tile?
Can I just extend my existing Cranbourne alfresco rather than build new?
Get your bench run sized and priced properly.
Send your wall length, usable depth and appliance wish list and we will size the run and come back with a written range within 1 business day.
We will chalk it out on your slab before anyone signs anything.
Full-size layout, appliance cut-outs checked against the specification sheets, gas load calculated on the day. Cranbourne, Berwick, Narre Warren, Hampton Park and Endeavour Hills.