Concrete Slab Cost WA 2026 - Get Free Quotes

What a Concrete Slab Costs in WA

A straightforward slab on a sandy Perth site runs $95 to $150 a square metre, which puts a six by nine metre shed slab at $5,100 to $8,100. An engineered slab on reactive ground reaches $150 to $220, and the difference is beams and steel, not a different grade of concrete. Engineering and a soil classification add $600 to $2,000 on top where they are required. Figures for every type of concrete job appear at concreting costs.

What you are buying above about $120 a square metre is structural capacity. Perimeter and internal beams, heavier mesh or bar reinforcement, deeper excavation and more concrete volume all follow from what the slab must carry and what the ground under it will do, and none of it is visible once the surface is trowelled. That is the awkward part of comparing quotes. The expensive slab and the cheap one look identical on day one.

Area improves the rate but less than on a driveway. A slab has formwork around its perimeter, beams that follow that perimeter, and set-out that does not scale down, so a small slab carries a heavy share of fixed cost while a large one spreads it, though the beam content stays proportionally similar. Doubling the area does not halve the rate. The rate does come down noticeably at scale. A difference of thousands between two shed quotes usually traces to the classification each assumed.

The base is a larger proportion of a slab cost than most people expect. Excavation, removal of unsuitable material and compacted fill add $25 to $55 a square metre, and on a site needing significant level correction or imported sand that figure climbs further. Perth sand keeps it at the lower end. Site works are quoted at excavation and earthmoving, and where a patio or verandah shares the slab, patio and verandah installation covers the structure.

Site Classification Under AS 2870

Every residential slab in Australia is designed against a site classification and it is the single most important line on a slab quote. AS 2870, the residential slabs and footings standard, sorts sites by how much the ground moves with changes in moisture, running from Class A for stable sand and rock through S, M, H1, H2 and E for increasingly reactive clay, with Class P covering problem sites. Classification drives the design, and the design drives the price. Holcim, Boral, Hanson and BGC batch most residential concrete across the Perth basin, and plant distance from your site shapes what is practical.

Western Australia sits unusually well on this scale. Large parts of metropolitan Perth are Class A on Spearwood and Bassendean sands, which is the least demanding classification available and something most eastern states suburbs never see, so a slab that would need a stiffened raft in Adelaide can often be a simple slab on ground here. Perth homeowners get a real saving from this. It is also why Perth slab rates look cheap by national comparison.

The advantage disappears in specific places and knowing where matters. Clay pockets through the eastern suburbs and Swan Valley, clay and laterite, the hard iron-rich gravel found through the Hills, along the Darling Scarp, and any site with uncontrolled fill all classify higher, and coastal Quindalup dune sand brings its own issues with loose material and reinforcement cover. A sandy neighbour tells you nothing about your own block. Classification applies to your block, not your street.

Class P is the classification nobody wants and it covers a range of problems. Uncontrolled fill, soft soils, sites subject to landslip or erosion, mine subsidence areas and anything outside the normal parameters all fall here, and a Class P site requires specific engineering instead of a standard design from the tables. Newer estates on filled ground are the common case. A geotechnical investigation is the only way to know. Beam depth and spacing come straight from the classification tables in the standard.

Getting a classification costs money and saves more. A soil test and classification report from a geotechnical consultant typically runs a few hundred dollars, and it either confirms a simple design is adequate or identifies a problem before your slab is sitting on it. You can buy the classification tables themselves from standards.org.au. Any structural slab should have one.

Slab Types Explained

A simple slab on ground is what most Perth shed and garage slabs are. A flat slab of uniform thickness, usually a hundred millimetres with mesh, sitting on compacted fill with a thickened edge around the perimeter to carry the walls, and on Class A sand that is frequently all the engineering required. It is the cheapest structural slab. It suits stable ground and nothing else. Class P is the one that changes a budget, and only a soil test will reveal it.

A stiffened raft adds beams and is the standard answer on reactive ground. Downturned beams run around the perimeter and across the slab in a grid, tying the whole floor into a stiff plate that moves as one unit when the soil beneath swells or shrinks, and the beam depth and spacing come from the classification. More reactive ground means deeper beams. That is where the additional cost sits.

A waffle raft achieves similar stiffness with void formers. Polystyrene pods sit on the ground with concrete ribs between them, producing a beamed slab without deep excavation, which suits sites where digging beams is difficult and gives good thermal performance. It sits on the ground instead of in it. Site preparation and levels have to be right for it to work.

Footing systems separate the structural support from the floor. Strip or pad footings carry the loads while a separate floor slab sits between them, which is used where a structure has concentrated point loads or where the floor and the structure need to move independently. Sheds with heavy portal frames sometimes need this. The building supplier's engineering will say if it applies. Uncontrolled fill from subdivision earthworks is the trap on newer estate blocks.

Which type suits you is an engineering decision, not a preference. The classification, the structure above and the loads it imposes together determine what is appropriate, and a concreter quoting a slab type without reference to either is guessing. Ask what the design is based on. Where the slab forms part of a larger build, concreting services sets out the scope.

Wind Regions and the Cyclonic North

Western Australia spans more wind regions than any other state and it changes slab design substantially. AS 4055 classifies housing sites by wind speed, with the southern half of the state in the non-cyclonic regions and the coast north of roughly Carnarvon in Region C and D, the cyclonic classifications, which apply through the Pilbara, the Kimberley and the Gascoyne coast. A slab in Karratha is not a slab in Kalgoorlie. The design difference between the two is substantial.

In cyclonic regions the slab resists uplift as well as carrying load. Wind acting on a shed or house roof generates suction that tries to lift the structure, and the slab and its footings are what hold it down, which means deeper edge beams, heavier reinforcement and a tie-down system engineered to transfer that force into the mass of the concrete. Standard southern hold-down details are inadequate up there. Expect fifteen to thirty per cent above an equivalent southern slab.

Tie-down is a continuous load path, not a single component. The connection runs from the roof through the frame to the bolts cast into the slab, and every link in that chain has to be rated for the design wind load, so the bolts, their embedment depth and their position all come from the structural engineering and not from a standard detail. Getting one link wrong compromises the lot. This is not an area for improvisation.

Building requirements in cyclonic areas are enforced through the permit process. The National Construction Code sets the framework nationally, administered through abcb.gov.au, and local governments in the north apply it with particular attention given the consequences of failure. Northern local governments enforce this closely. Building a shed to a Perth specification in the Pilbara will not pass. Waffle rafts also give useful thermal performance in a habitable building.

Southern WA has its own wind considerations at a lower level. Exposed coastal sites through the South West and Great Southern classify higher than sheltered suburban ones even within the non-cyclonic regions, which affects tie-down requirements on sheds and patios. Terrain and shielding both feed into it. Your building supplier should nominate the wind classification for the address.

Shed Slabs and Hold-Down Bolts

A shed slab is engineered around the shed, not the other way round. The supplier's engineering drawings specify the slab edge detail, the footing requirements under each frame connection, the bolt type and the exact bolt positions, and those drawings need to reach the concreter before the slab is quoted let alone poured. This sequence catches people out constantly. Ordering the shed after the slab is the wrong order.

Hold-down bolts have to be cast in position while the concrete is wet. Cast-in bolts develop their full capacity through embedment in the concrete, and getting them within a few millimetres of the specified positions is what allows the shed frame to bolt down without modification, which is why a template is used instead of a tape measure. There is no correcting it once the concrete goes off. The concrete sets around whatever position they were in. Mesh and bar are specified to AS 4671, and the concrete itself is supplied under AS 1379.

Chemical anchors are the fix when bolts are wrong and they are a compromise. Drilling and chemically anchoring bolts into cured concrete can achieve adequate capacity where the engineering permits it, but in cyclonic regions and on heavily loaded frames the engineer may not accept them, leaving expensive remediation. Getting the positions right beforehand costs nothing at all. Sit the template on the steel and check it against the drawings the day before.

The slab edge detail depends on how the shed sheeting meets the concrete. Some systems need a rebate so the sheeting sits below floor level and keeps water out, others sit on top of the slab edge with a flashing, and getting this wrong means either water running in or an untidy junction. The shed supplier nominates which detail applies. Kit selection and erection sit at shed and garage construction.

Slab size relative to shed size needs deciding early. A slab matching the shed footprint exactly is the cheapest option, while an apron extending beyond the doors gives somewhere to work and stops sand tracking inside, and the apron is far cheaper poured at the same time than added later. Think about how you will use the space. An extra metre at the door is usually money well spent. Region D applies to parts of the Kimberley coast and carries the heaviest requirements.

Attached Garage Slabs

A garage slab attached to a house has more constraints than a freestanding one. It has to work with the house floor level, the driveway approach, the door track and the damp proof course, the barrier built into the brickwork that stops moisture rising into the walls, all at once, and those four requirements can pull in different directions on a site with any fall. Set-out matters more than anywhere else on a domestic slab. Getting it wrong shows up as water inside.

The junction with the house wall needs care. A slab poured hard against a wall can bridge the damp proof course and carry moisture into the brickwork, so the finished level must sit below the course with an appropriate separation, and an isolation joint lets the two move independently. This is a common defect in owner-built work. Rising damp in a wall next to a newer slab is usually this.

A rebate for the garage door track is much cheaper formed than cut. Where a panel or roller door needs a recess for its track or seal, forming it during the pour costs almost nothing while cutting it into cured concrete is slow, dusty and imprecise, so the door specification needs to be known beforehand. Door manufacturers publish the rebate dimensions. Garage door work is priced at garage door installation. Wind classification is nominated by the building supplier for the specific address.

Fall to the door is a small detail that matters daily. A garage slab wants a slight fall toward the opening so water brought in on a car runs out rather than pooling at the back, and a flat or reverse-falling slab collects water against the house wall. Two per cent is generally plenty. Nobody notices it when it is right.

Vapour Barrier and Termite Management

A vapour barrier under a habitable slab is standard practice and worth understanding. A polythene membrane laid over the compacted base stops ground moisture rising through the concrete into the building, protecting floor coverings and reducing dampness, and it needs to be laid without punctures and lapped properly at joins to work. A thin layer of sand, called blinding, is spread over the base first so stones cannot puncture the sheet from below. A punctured membrane achieves very little.

Whether a shed slab needs one depends on what goes inside. A slab storing a car and a mower does not particularly need a membrane, whereas one intended for a workshop, a gym, storage of anything moisture sensitive, or eventual conversion to a habitable space certainly does. There is no way to add one after the pour. Spending a little now preserves the option. The bolt template is usually supplied with the shed kit for exactly this reason.

Termite management is a building requirement in most of Western Australia. Perth and the South West have active termite populations, and slab penetrations are the common entry path, so physical barriers at pipe penetrations and around the slab perimeter are standard on habitable buildings and worth considering on any structure holding timber. The system is specified as part of the build. It cannot be retrofitted into a slab edge.

Inspection zones are part of the strategy. Termite management on a slab generally requires an exposed edge that can be visually inspected, which means paving, garden beds and soil should not be built up over the slab edge afterwards, and this constrains landscaping around a new building. Householders undo it regularly without realising. Bed heights and edging around a building are covered at landscaping.

Levels and the Damp Proof Course

Finished floor level is the decision everything else follows. It has to sit high enough above surrounding ground for water to drain away from the building, low enough that the approach from the driveway works, and below any adjoining damp proof course, which on a sloping site requires genuine set-out instead of a rule of thumb. Get it wrong high and the approach becomes a step. Get it wrong low and water comes in.

Surface drainage around the slab matters as much as the slab itself. Ground should fall away from the edge on all sides, downpipes should discharge clear of the building, and a slab sitting in a depression collects water no matter how well it was poured. Perth sand drains well and forgives a lot. Clay sites in the Hills forgive nothing.

Adjoining structures constrain the levels available. A new slab beside an existing house, patio or driveway has to meet each of them sensibly, and where those existing levels conflict the resolution is a design exercise before the pour, not a decision on the day. Survey levels are worth the modest cost on a complicated site. Guessing is how thresholds end up wrong.

Local government requirements can affect levels too. Some councils specify maximum finished floor levels relative to the street or the boundary, particularly in areas with drainage constraints or flood considerations, and those requirements are checked at building permit stage. Local government contacts across the state are listed through wa.gov.au. Confirm the position before finalising the design. An apron at the shed door keeps sand out and gives somewhere to work.

Services Through the Slab

Anything that needs to come up through the slab has to be in place before the pour. Sewer and waste points, water supply, electrical conduit, data cabling and any provision for a future fitout all sit in the base and rise through the concrete, and adding them afterwards means core drilling and compromise. Planning at this stage pays for itself repeatedly. A workshop with power in the wrong place is a lifetime irritation.

Set-out for plumbing points needs the finished layout, not a rough idea. Waste points serving a toilet, basin or laundry have to be within tolerance of the fixture positions, and a point fifty millimetres out can mean rearranging a whole layout, which is why the plumber sets out from the same drawings as everyone else. An approximate position is not good enough for a waste point. Confirm the layout before anyone sets out.

Spare conduit is cheap insurance against future work. Running spare conduit through the slab to positions you might one day want power, data or a hose costs very little while the base is open, and it saves core drilling or surface mounted trunking later, which is a common regret on shed and garage slabs. Cap the ends and record the positions. Photographing the base before the pour is worth doing.

Existing underground services need locating before excavation. Water, sewer, gas, power and reticulation all run through Perth blocks at shallow depth, and a competent contractor uses a location service before breaking ground instead of discovering them with a bucket. Almost every Perth block has reticulation somewhere in it. Cutting a mainline is a minor problem, cutting fibre is not.

Tying Into an Existing Slab

Joining a new slab to an old one needs deciding, not assuming. The two can be structurally connected with dowels so they act together, or deliberately separated with an isolation joint so each moves independently, and which is appropriate depends on the ground, the structures and what the engineer specifies. Doing neither is the common mistake. Concrete butted against concrete with no detail will crack at the junction.

Dowelled connections transfer load across the joint. Steel dowels drilled and epoxied into the existing slab, projecting into the new pour, keep the two surfaces level as they move, which suits an extension where a step at the junction would be unacceptable. It relies on the existing slab being sound. Dowelling into a slab that is already failing achieves nothing. Sand blinding under the membrane protects it from stones in the base.

Isolation joints suit situations where movement is expected. A compressible filler between the old and new lets each move on its own, which is appropriate where the ground differs, where the structures are independent, or where the existing slab has a history of movement. A visible joint is the trade-off. It is far better than an unplanned crack.

Matching levels to an existing slab is harder than it sounds. Old slabs settle, and the level you measure today is not the level it was poured at, so a new slab set to match may end up slightly high or low as the old one continues to move. Survey the existing slab properly before setting levels. Building the tolerance into the design is better than discovering it afterwards.

Approvals and Engineering

A slab supporting a structure generally needs a building permit and the slab design forms part of it. A shed, a garage, a patio with footings or a habitable addition all require approval from the local government, and the application includes structural details showing the slab, its reinforcement and its footings, which is where the engineering earns its cost. A slab on its own with nothing on it is different. Ring the council and confirm what applies to your project. Termite inspection zones need to stay clear once landscaping goes in.

Structural certification comes from an engineer, not the concreter. A qualified structural engineer designs the slab against the site classification, the loads and the wind region, and provides documentation that supports the permit application, and for a standard shed the supplier's engineering usually covers it. Non-standard structures need their own design. Ask who is providing the certification before work starts.

Above a certain contract value, registration requirements attach to the builder. Building work over a set value requires a registered builder and carries contract and home indemnity insurance requirements, which applies to a house extension and generally not to a shed slab, though the boundary is worth checking on a substantial project. Requirements are administered at state level. Licensing information across jurisdictions sits at ablis.business.gov.au. Termite management systems for slabs are covered by AS 3660, which matters across Perth and the South West.

Inspections happen at defined stages on permitted work. Reinforcement is typically inspected before the pour because it cannot be verified afterwards, and photographs of the steel, the bar chairs and the membrane are worth taking regardless of whether an inspector attends. File the photographs alongside the permit paperwork. They are the only evidence of what went in. Survey levels are cheap compared with a threshold that has to be rebuilt.

Site safety obligations sit with the business doing the work. Digging, machinery on site, pumping and any cutting of cured concrete each bring duties for the business, overseen by worksafe.wa.gov.au. A crew managing these properly is a reasonable proxy for the rest of their work. Corners cut on safety are rarely the only corners cut.

Curing and Early Strength

A slab gains its strength over weeks and the first days matter most. Concrete cures through a chemical reaction that needs moisture, so a slab allowed to dry out early develops a weak surface and reduced strength throughout, which is why crews cover, spray or wet cure instead of simply walking away. The concrete looks finished long before it is. That gap causes most of the damage.

Summer here is harder on a curing slab than almost anywhere else in Australia. High temperatures accelerate the reaction while the dry easterly strips surface moisture faster than it can be replaced, producing plastic shrinkage cracking and a dusty surface, and both are permanent. Early morning pours and evaporative retarders are the standard response. Postponing for weather is the right call every time.

Put weight on too soon and the consequence surfaces months afterwards. Foot traffic is generally fine after a day or two, vehicles after about a week, and heavy loads or a shed frame only when the engineer or concreter says so, and a slab driven on at three days may crack at three months. Nothing appears at the time, which is the difficulty. That is exactly why people do it.

Northern WA has the opposite problem at scale. Ambient temperatures through the build-up make curing genuinely difficult, and crews there use chilled water, ice, admixtures that slow the set, and night pours as routine practice, not exceptional measures. Crews who work the north year round know how to handle it. A Perth crew travelling north should be asked how they intend to manage it.

Slab Finishes and What Goes on Top

The finish on a structural slab is a separate decision from the structure and it deserves thought. Machine trowelling produces a dense, hard surface that sweeps clean and takes coatings well, whereas a light broom sacrifices some of that for grip, and how you intend to use the space decides which you want. Trowelled surfaces are slippery when wet. Anything that will see water wants texture. Photographing the base with a tape in frame records the positions accurately.

Levelness matters more than people expect on a workshop slab. A slab intended for machinery, a hoist, a workbench or storage racking needs to be flat within a reasonable tolerance, and a wavy surface that looks fine underfoot becomes obvious once a long straightedge or a level machine base sits on it. Say what the space is for. Flatness tolerance is a specification, not an accident.

Coatings and toppings go on later and the slab finish affects them. Epoxy and polyurethane coatings need a properly prepared surface and adhere better to a trowelled slab, while a heavily broomed surface needs grinding first, which adds cost to a job you may not have planned yet. Think about the eventual finish now. Epoxy systems and their preparation requirements sit at garage flooring.

Polishing a structural slab is possible where it was poured with that in mind. Grinding back a cured slab exposes the aggregate and produces a hard, low maintenance floor, though it needs adequate cover over the reinforcement, a suitable aggregate in the mix and a slab flat enough to grind evenly. It cannot be decided afterwards on any slab. Tell the concreter if polishing is a possibility.

Surface levelling products can rescue a slab that is out of tolerance. Self levelling compounds and screeds correct a surface that is flat enough structurally but not flat enough for a floor covering, which is a common requirement before vinyl, tile or timber goes down. It is an additional trade and cost. That work is priced at floor levelling and screeding.

Choosing a Concreter for Slab Work

Slab work rewards experience more than most concrete jobs because so much of it is invisible afterwards. A crew that pours structural slabs regularly understands beam set-out, bar chair spacing, membrane laps and bolt templates as routine, whereas one that mainly does driveways may treat a shed slab as a thicker driveway. Ask what proportion of their work is structural. The answer tells you a good deal.

Ask whether they work from engineering drawings as a matter of course. A concreter who expects to receive structural drawings, reads the beam schedule and sets out from it is operating properly, while one who offers to pour a shed slab without seeing any documentation is taking a risk on your behalf. The drawings exist for a reason. Working without them puts the liability somewhere uncomfortable. Dowel spacing and diameter both come from the engineering rather than habit.

Insurance and business credentials are the baseline. A current ABN, public liability cover and, where the work sits within a larger building contract, the appropriate registration all matter, and any established business produces the documentation without hesitation. There is no dedicated concreting licence in this state. That makes the checks you can do more important.

Nothing in a quote can sign away your rights over defective work. A slab that fails because steel sat on the sand or the base was never compacted is a workmanship issue, and the ACCC explains what that entitles you to. Record what went in before the concrete covers it. Photographs of the steel are the most useful record you will ever take.

References from a few years back are worth more than recent ones. Any slab looks acceptable in its first month, whereas one that has been through several seasons shows whether the base was compacted properly and whether the joints and beams were where they should have been. Ask for an address you can look at. Anyone doing this work regularly can name a few. There is no point dowelling into concrete that is still on the move.

Perth Metro Costs

Perth slab rates are competitive nationally and the site classification is the main reason. Class A sand across much of the metropolitan area means simpler designs, less steel, shallower beams and easier excavation than equivalent sites in the eastern states, and that flows straight through to the price. What separates one Perth quote from another is usually the classification and the structure above, not the suburb. Access and level correction account for most of the rest.

Growth corridor blocks are the simplest slabs in the state, with one caveat. Flat Class A sand, open access and standard shed sizes make for efficient work, though newer estates can carry uncontrolled fill from the subdivision earthworks that changes the classification entirely. A soil test resolves it quickly. Assuming sand because the surface looks sandy is the risk.

The Hills are where slab costs move furthest from the metropolitan average. Slope means cut and fill or a stepped design, clay and laterite mean a higher classification with deeper beams, and rock means excavation that a small machine cannot handle, all of which compounds. Retaining is frequently involved as well. What retaining adds is broken down at retaining wall costs.

Coastal sites bring reinforcement cover into the picture. Salt in the air and in the ground accelerates corrosion of reinforcement where cover is inadequate, and the specification for cover is higher near the coast than inland, which is a design detail, not a construction shortcut. It costs very little to get right. Spalling concrete twenty years on costs a great deal. Reinforcement inspections happen before the pour because nothing can be checked after.

Regional WA Costs

Regional slab costs are driven by concrete supply and, in the north, by wind region. A site well beyond a batching plant faces genuine constraints on delivery, and a cyclonic classification adds engineering, steel and beam depth that a southern slab never needs, so the two effects compound above Carnarvon. Distance and wind region are the first two questions. The rest of the quote follows from those two answers.

The Pilbara and Kimberley premium is not simply remoteness. Cyclonic wind design means deeper beams and heavier steel, heat means night or early pours with chilled water and admixtures, and freight on both concrete materials and reinforcement is substantial, which together explain a figure well above southern rates. Contractors based in the region price it accurately. A southern quote for a northern job is usually wrong.

Great Southern and South West ground is a genuine change from Perth. Clay soils through the agricultural areas and around Albany classify higher than metropolitan sand, and wetter winters mean base preparation and pour timing both need more thought. A soil test is more valuable here than in Perth. Assuming a metropolitan design is a mistake.

Stacking pours into one visit is where country jobs save money. One delivery covering the shed slab, the paths and the driveway costs far less than three separate call-outs to the same address. Work out everything you want poured first. Driveway work is priced at concrete driveway costs.

What to Look Out For

Ask what site classification the quote is designed against, because it is the line that determines everything else. AS 2870 sorts sites from Class A for stable sand through to Class P for problem ground, and while much of metropolitan Perth is genuinely Class A, clay pockets, Hills laterite, coastal dune sand and any block with uncontrolled fill all classify higher. A soil test costs a few hundred dollars and either confirms a simple design or catches a problem before your slab is sitting on it. Do not assume Class A because the surface looks sandy.

Get the shed or building engineering before the slab is quoted, not after. The supplier's drawings specify the edge detail, the footings under each frame connection, the bolt type and the exact bolt positions, and cast-in hold-down bolts have to be within a few millimetres of those positions while the concrete is wet. Chemical anchors drilled in afterwards are a compromise the engineer may not accept, particularly in cyclonic regions. Check the bolt template against the drawings before the truck arrives. Chilled water and ice are routine additions on northern pours through summer.

Confirm the wind classification if the property is anywhere north of about Carnarvon. In Region C and D the slab resists uplift as well as carrying load, which means deeper edge beams, heavier reinforcement and an engineered tie-down running from roof to slab as a continuous load path. A shed slab detail perfectly adequate in Perth is not compliant in Port Hedland, and expect fifteen to thirty per cent above an equivalent southern slab. Certification is not optional in those regions.

Settle everything that passes through the slab before anyone sets out. Sewer and waste points, water, electrical conduit, data and any provision for a future fitout all sit in the base and rise through the concrete, and adding them later means core drilling and compromise. Waste points have to be within tolerance of the fixture positions, so an approximate layout is not adequate. Spare conduit costs very little while the base is open and saves surface mounted trunking for the life of the building.

Photograph the reinforcement, the bar chairs and the membrane before the pour. None of it can be verified once concrete is down, and on permitted work an inspection usually happens at that stage for exactly this reason. Check that mesh sits on chairs within the slab rather than on the ground, that laps are correct, and that any vapour barrier is unpunctured and properly lapped. Hang on to the docket, which is the record of what strength turned up.

What to Look for in a Quote in WA

A slab quote should state the area and dimensions, the site classification it assumes, the slab type and thickness, the reinforcement and how it is supported, the beam sizes and locations, the concrete strength and whether a vapour barrier is included. It should price excavation, base preparation and any imported fill separately, and say who provides the structural certification. Ask whether the engineering is included or extra. Site classification and the beam schedule are the two items most likely to separate quotes that look comparable per square metre.

Brief every concreter from the same documents. The shed or building engineering drawings, the soil classification if you have one, the area and levels, access for a truck and pump, and what services need to pass through all shape the figure, and a quote given without the structural drawings is an estimate at best. Photographs of the site and access help. Quotes built on different classifications cannot be compared at all.

Ask who carries responsibility if the slab moves. A slab designed and certified by an engineer against a classification report has a clear chain of responsibility, whereas one poured to a concreter's judgement without documentation leaves you carrying the risk. That distinction matters years later, not on the day. It is the strongest argument for paying for classification and design. Trowelled floors take epoxy coatings far better than broomed ones.

Four things want resolving before a truck is ordered: the classification, the structural design, the set-out for bolts and services, and how heat will be handled. Get a soil test where there is any doubt, have the structural drawings in hand, confirm bolt and service positions against the final layout, and agree how a hot day will be handled. For the wider picture on rates and finishes, see concreting costs. Get those right and the slab will outlast whatever you put on it.