Garage & Shed Concrete Slabs NZ

Concrete Services

Strong and reliable garage and shed concrete slabs

Need a strong, level base for a new garage, workshop or shed?

Concrete Services Direct can help arrange quotes for garage and shed concrete slabs throughout New Zealand, from smaller residential projects through to larger workshops and vehicle storage buildings.

Garage concrete slabs
Shed and workshop slabs
Concrete floors for vehicle storage
Slabs for new builds and existing properties
Reinforced concrete options
Preparation, boxing and concrete pouring
Vehicle and equipment load considerations
Concrete slab services throughout New Zealand
Free, no-obligation quotes

Get A Free Quote

Concrete Slabs for Garages, Sheds & Workshops

A garage or shed concrete slab provides the foundation and finished floor for the building above it.

The right slab needs to do more than simply create a flat surface. It may need to support vehicles, storage systems, machinery, workbenches, shelving, tools and the building structure itself.

For larger garages and workshops, factors such as slab thickness, reinforcing, vehicle loads, door levels and drainage can all become important.

Whether you’re planning a single garage, detached workshop, storage shed or larger outbuilding, tell us about your project and request a free, no-obligation concrete slab quote.

Garage Concrete Slabs

A garage concrete slab provides a durable floor capable of handling regular vehicle use while also forming part of the building’s overall foundation system.

Garage slab projects may include:

Single garages
Double garages
Triple garages
Attached garages
Detached garages
Garages with workshop areas
Vehicle storage buildings
Car and trailer storage

The slab needs to work with the garage structure, door openings, driveway levels and drainage.

Getting these details right from the beginning can help avoid awkward changes in level or poor transitions between the garage and surrounding concrete.

Shed Concrete Slabs

Concrete provides a practical base for a wide range of sheds.

Projects can include:

Garden sheds
Storage sheds
Tool sheds
Utility buildings
Larger storage sheds
Rural sheds
Workshop buildings

A concrete shed floor creates a clean, stable and durable surface that is easier to use than bare ground or gravel.

The exact slab requirements depend on the size of the shed, construction method and what will be stored inside.

A small garden shed and a large vehicle storage shed should not automatically be built on the same type of slab.

Workshop Concrete Slabs

Workshops often place heavier and more concentrated loads on a concrete floor than a standard domestic garage.

A workshop concrete slab may need to accommodate:

Vehicles
Machinery
Tool cabinets
Workbenches
Storage racks
Compressors
Vehicle hoists
Welding equipment
Heavy shelving

If the workshop will contain substantial machinery or fixed equipment, these loads should be considered before the slab is poured.

Planning heavy-load areas early can reduce the need for cutting, strengthening or modifying the slab later.

New Garage Slabs

For a new garage, the slab is often one of the first major stages of construction.

The project may involve:

Site clearing
Excavation
Base preparation
Formwork
Reinforcing
Service penetrations
Concrete placement
Surface finishing
Curing

The concrete slab may also need to incorporate thickened edges, foundations, anchor points or structural detailsdepending on the garage design.

Where building plans or engineering drawings are available, they should be used as the basis for the concrete work.

New Shed Slabs

A new shed slab can be relatively straightforward or form part of a more complex building project.

Before construction begins, useful questions include:

What size is the shed?
Will vehicles enter it?
Will heavy equipment be stored inside?
How will the shed be anchored?
Are plumbing or electrical services required?
Does the slab need to form part of the building foundation?
Will the finished floor remain exposed?

These factors help determine the appropriate slab design and preparation.

Concrete Slabs for Detached Garages

Detached garages are common on existing properties and can be positioned away from the main house.

This can create additional considerations around:

Site access
Driveway extensions
Drainage
Finished slab height
Power and services
Distance from boundaries
Ground conditions

Where the garage is located behind or beside an existing house, access for excavation equipment and concrete delivery may also need to be considered.

A detached garage project often works best when the slab, vehicle access and surrounding concrete are planned together.

Concrete Slabs for Attached Garages

Attached garages need to integrate closely with the main building.

The slab level can affect:

Interior floor levels
Garage door height
Entry doors into the house
Cladding
Drainage
Driveway connection

For this reason, accurate slab levels are particularly important.

The concrete work should follow the plans and structural requirements for the overall building rather than treating the garage as a separate standalone slab.

Garage Floor Levels

One of the most important details in garage slab construction is the finished floor level.

The slab needs to work with:

Garage door tracks
Vehicle entry
Driveway levels
Exterior drainage
House floor levels
Internal access doors
Building cladding

If the slab is too high or too low, the effects can flow into several other parts of the project.

Correct set-out before pouring helps prevent these problems.

Garage Door Thresholds

The point where the driveway meets the garage floor needs careful consideration.

A good transition should allow vehicles to enter comfortably while also managing water appropriately.

Potential considerations include:

Driveway slope
Garage floor level
Door seal
Drainage channels
Water runoff
Threshold height

Poorly considered levels can result in water flowing into the garage or an awkward vehicle transition.

This should be addressed during the planning and boxing stage.

Garage Slab Drainage

Garage floors may require drainage depending on how the space will be used.

Potential drainage considerations include:

Surface falls
Doorway drainage
Floor wastes
Wash-down areas
Water entering from vehicles
Driveway runoff

Not every residential garage requires the same solution, but the slab should be planned so water does not become trapped where it causes problems.

For workshops or commercial garages, drainage requirements may be more significant.

Concrete Slabs for Vehicle Hoists

If you’re planning to install a vehicle hoist, identify this before the slab is designed.

Vehicle hoists can create concentrated loads at their fixing points and may require:

Greater slab thickness
Additional reinforcing
Specific concrete strength
Minimum distances from slab edges
Dedicated thickened areas

The hoist manufacturer may provide concrete foundation requirements.

These specifications should be considered before the slab is poured rather than after the workshop is complete.

Heavy Vehicle Garage Slabs

Garages intended for motorhomes, trucks, heavy trailers or commercial vehicles may require a stronger slab than one used only for ordinary cars.

The design may need to take into account:

Vehicle weight
Tyre loads
Frequency of use
Turning areas
Slab thickness
Reinforcing
Base preparation

If heavier vehicles will regularly use the garage, mention this when requesting your quote.

The slab should be designed around the actual loads rather than assuming standard residential use.

Shed Slabs for Machinery & Equipment

Sheds used for machinery, farm equipment or commercial storage can also require higher-capacity concrete floors.

Potential loads might include:

Tractors
Ride-on equipment
Heavy shelving
Tanks
Machinery
Pallet storage
Commercial equipment

These loads should be identified early so the concrete specification, reinforcement and base preparation can be considered appropriately.

Reinforced Garage & Shed Slabs

Many garage, shed and workshop slabs use reinforcing mesh or steel.

Reinforcement can help control cracking and improve how the slab performs under load.

Depending on the project, reinforcing may include:

Steel mesh
Reinforcing bars
Thickened edge reinforcing
Starter bars
Structural steel connections

The amount and type of reinforcing depend on the slab design, dimensions and expected loads.

Where plans specify reinforcing, the concrete work should follow those details.

Garage & Shed Slab Thickness

There is no single slab thickness suitable for every garage or shed.

The appropriate depth depends on factors such as:

Building size
Vehicle loads
Machinery
Ground conditions
Base quality
Reinforcing
Structural design

A small storage shed and a workshop containing heavy vehicles can have very different requirements.

For this reason, slab thickness should be based on the intended use of the building, not just a generic rule.

Ground Preparation for Garage & Shed Slabs

A durable slab starts with good preparation underneath it.

The site may need:

Vegetation removal
Excavation
Topsoil removal
Levelling
Base material
Compaction
Drainage preparation

Poorly compacted ground can settle over time and contribute to cracking or movement.

For larger garages and workshops, the ground preparation can be just as important as the thickness of the concrete itself.

Concrete Slab Base Course

The base beneath the slab helps provide stable support.

Depending on the site, base preparation may involve placing and compacting suitable aggregate material.

The goal is to create an even, firm foundation before concrete is poured.

Where filling is required to raise the building area, proper compaction becomes particularly important.

Large amounts of loosely placed fill can settle after construction if not prepared correctly.

Boxing & Formwork

Formwork creates the edges and levels of the slab.

For garages and sheds, boxing may also need to accommodate:

Garage door recesses
Thickened slab edges
Foundation beams
Steps
Different floor levels
Equipment pads

Accurate boxing helps ensure the finished slab matches the building dimensions.

This is particularly important where wall framing or prefabricated building components will be installed directly onto the concrete.

Garage & Shed Foundations

Some garages and sheds require more than a simple flat slab.

Depending on the building design, the concrete work may include:

Perimeter foundations
Thickened slab edges
Ground beams
Pad foundations
Reinforcing cages
Structural anchor points

The foundation and floor slab may form one integrated system.

For larger structures, building plans or engineering drawings should establish how the concrete needs to be constructed.

Anchoring Buildings to Concrete Slabs

Garages and sheds need to be securely connected to their foundations.

The required anchoring method depends on the building system.

It can involve:

Cast-in anchors
Bolts
Starter bars
Hold-down systems
Post connections

The placement of structural fixings may need to be coordinated before or during the concrete pour.

For prefabricated garages or sheds, the building supplier may provide specific slab and anchoring requirements.

Services Through Garage & Shed Slabs

A garage or workshop may need services installed through or beneath the slab.

These can include:

Electrical conduits
Water lines
Drainage
Floor wastes
Compressed air lines
Data cables
Plumbing

If services will pass through the concrete, their locations should be planned in advance.

Cutting into a new slab later to install something that could have been positioned beforehand can add unnecessary work.

Garage Slab Surface Finishes

The surface finish of the slab should suit how the garage will be used.

Trowel-Finished Garage Floors

A trowelled finish can create a relatively smooth floor suitable for many residential garages and workshops.

Textured Areas

Some entrance or external sections may use more surface texture depending on exposure to weather and water.

Floor Coatings

Garage floors can also receive coatings or other treatments after the concrete has cured.

If a specific coating system is planned, check what type of concrete surface preparation or finish it requires.

Workshop Floor Finishes

Workshops may need a floor that is easy to clean and suitable for equipment movement.

Depending on the intended use, the slab may later receive:

Concrete sealer
Epoxy coating
Industrial floor coating
Polished finish

The final floor treatment should be considered before the slab is poured where possible.

Some coating or polishing systems work best with specific concrete finishing practices.

Polished Concrete Garage Floors

Some homeowners choose polished concrete for higher-end garages, workshops or multi-purpose spaces.

If polishing is planned, the slab needs to be treated as a visible finished surface from the beginning.

Factors such as concrete placement, aggregate and surface consistency can influence the final appearance.

This is different from a standard garage slab that will later be covered or coated.

Garage Slab Extensions

Existing garage slabs can sometimes be extended when:

The garage is being enlarged
A workshop area is being added
An additional bay is required
Storage space is being increased

The new slab needs to integrate with the existing concrete and building structure.

Differences in age can mean new concrete does not visually match the original slab exactly.

Structural connections may also need consideration where the extension forms part of the building.

Shed Slab Extensions

A shed slab can also be extended to accommodate:

Larger storage areas
New bays
Lean-to structures
Workshops
Additional equipment

As with garage extensions, the project should consider the connection between old and new concrete.

Where the building itself is being extended, structural plans may establish how the new slab needs to join the existing foundation.

Replacing an Old Garage Slab

Older garage floors can become badly cracked, uneven or damaged.

Replacement may be considered where:

The slab has significant movement
Large sections have sunk
Cracking is severe
The building is being rebuilt
Floor levels need changing
Drainage needs correcting

Replacing a garage slab can be a substantial project because existing walls or structural elements may interact with the concrete.

If the garage remains in place, the condition of the building and foundation should be assessed before deciding on the best approach.

Replacing a Shed Slab

Damaged or unsuitable shed slabs can also be replaced.

This may be appropriate when:

The original slab is too thin
Ground movement has caused major cracking
A larger shed is planned
Heavy equipment will be installed
The slab is no longer level

If the replacement slab will support a new building, the new structure’s requirements should be established before concrete work begins.

Garage Concrete Slab vs Pavers

For enclosed garages, concrete is generally much more practical than individual pavers.

A concrete slab provides:

A continuous floor
Stable vehicle support
Easier movement of tools and equipment
Better integration with walls
Structural anchoring options
A suitable base for floor coatings

Pavers may be useful for exterior parking areas, but a reinforced concrete slab is typically better suited to the enclosed garage environment.

Concrete Slab vs Gravel Shed Floor

Gravel can be adequate for some simple storage sheds, but it does not provide the same finished surface as concrete.

A concrete shed floor can offer:

Cleaner storage
Better moisture separation
Stable shelving
Easier sweeping
Improved equipment movement
A level building floor

For sheds used regularly as workshops or vehicle storage spaces, concrete can provide a much more practical long-term surface.

Concrete Garage Aprons

A garage apron is the concrete area immediately outside the garage door.

It can provide a smooth transition between the garage floor and driveway.

Garage aprons can help with:

Vehicle access
Drainage
Door thresholds
Surface transitions
Protecting the area directly outside the garage

In some projects, the garage apron may be poured as part of the driveway rather than the main garage slab.

Planning both areas together helps achieve better levels.

Connecting Garage Slabs to Driveways

The connection between the garage and driveway is one of the most important practical details.

The two surfaces should work together to provide:

Comfortable vehicle access
Appropriate drainage
Suitable levels
Minimal unnecessary steps or lips

If a new garage slab and driveway are both being constructed, coordinating them at the same time can make the overall project easier to plan.

Concrete Shed Ramps

Some sheds or workshops need a ramp where vehicles or machinery enter the building.

Concrete ramps can provide access for:

Ride-on mowers
Motorcycles
Trailers
Machinery
Wheelbarrows
Workshop equipment

The slope and surface texture should suit the intended use.

For heavier vehicles or equipment, the ramp design should also account for the loads being applied.

Concrete Slabs for Rural Sheds

Larger rural properties may require concrete floors for:

Farm workshops
Machinery sheds
Storage buildings
Utility sheds
Equipment areas

Rural sites can present different challenges from urban properties, including longer access distances and larger floor areas.

If the slab will carry tractors, machinery or heavy vehicles, these loads should be identified during planning.

Commercial Garage & Workshop Slabs

Commercial garages and workshops can place substantial demands on concrete floors.

Potential uses include:

Mechanical workshops
Vehicle servicing
Fleet storage
Trade workshops
Light industrial premises
Equipment maintenance

The slab may need to support:

Vehicle hoists
Commercial vehicles
Machinery
High traffic volumes
Storage racks

For these projects, structural specifications, floor flatness, drainage and joint layout may all need more detailed consideration.

What Is Involved in Pouring a Garage or Shed Slab?

The exact process depends on the building, but typical stages include:

1. Planning & Set-Out

The slab position, size and finished levels are established.

2. Excavation

The site is excavated to create room for the base and concrete.

3. Base Preparation

Suitable material is placed and compacted to provide a stable foundation.

4. Formwork

Boxing is installed around the slab and any required foundation elements.

5. Services

Electrical, plumbing or drainage services are positioned where required.

6. Reinforcement

Mesh, reinforcing bars or other structural steel are installed.

7. Pre-Pour Checks

Dimensions, levels, reinforcement and services are checked before concrete placement.

8. Concrete Pour

Concrete is delivered and placed throughout the prepared slab area.

9. Levelling & Finishing

The surface is finished to the required floor level and texture.

10. Curing

The concrete is allowed time to gain strength before heavy loads or building work are applied.

How Much Does a Garage Concrete Slab Cost?

The cost of a garage slab depends on the complete scope of work, not simply the amount of concrete.

Factors can include:

Garage size
Slab thickness
Excavation
Ground conditions
Base preparation
Reinforcement
Formwork
Foundations
Concrete strength
Site access
Drainage
Service penetrations
Surface finishing
Concrete pumping
Project location

A standard single garage on an accessible site can be very different from a large workshop requiring heavy-duty reinforcing and engineered foundations.

A project-specific quote provides the best indication of cost.

How Much Does a Shed Concrete Slab Cost?

Shed slab pricing varies for the same reasons.

Important factors can include:

Shed dimensions
Building type
Intended loads
Site access
Excavation
Concrete thickness
Reinforcing
Base preparation
Anchoring requirements
Finished floor requirements

Providing the shed plans or manufacturer’s slab specification can make quoting more accurate.

Do I Need Shed Plans Before Getting a Concrete Quote?

For small sheds, approximate dimensions may be enough for an initial enquiry.

For larger or structural buildings, plans can be very useful.

They may show:

Slab dimensions
Foundation details
Anchor points
Reinforcing
Door locations
Structural loads

If you’re buying a prefabricated shed, ask the supplier whether they provide a concrete slab plan or foundation specification.

Do Garage Slabs Need Building Consent?

The slab may form part of a building project that requires consent.

The consent requirements depend on the size, design and type of garage or shed.

Where consent or approved plans apply, the slab should be constructed according to those requirements.

Any necessary inspections should also take place before concrete is poured.

Do Garage & Shed Slabs Need Engineering?

Some buildings can use standard foundation designs, while others require specific engineering.

Engineering may be relevant for:

Large garages
Heavy buildings
Poor ground conditions
Sloping sites
Commercial workshops
Heavy machinery
Vehicle hoists
Unusual structural designs

If engineering drawings are available, provide them as part of the quote request.

How Long Does a Garage Slab Take?

The timeframe varies depending on project size and site preparation.

The complete job may involve:

Excavation
Base preparation
Boxing
Reinforcement
Services
Inspections
Concrete placement
Finishing
Curing

The concrete pour itself can be relatively quick compared with the preparation required beforehand.

Weather and coordination with the building contractor can also affect scheduling.

How Long Before a Garage Can Be Built on the Slab?

Concrete continues gaining strength after it is poured.

The appropriate time before framing, wall panels or other building loads are installed depends on the concrete specification and project requirements.

Follow the builder, engineer or concrete contractor’s project-specific advice rather than assuming the slab is ready simply because the surface has hardened.

How Long Before You Can Drive on a Garage Slab?

Vehicles should not be driven onto newly poured concrete immediately.

The required curing time depends on the concrete, conditions and vehicle weight.

Heavy vehicles can place substantial loads on concrete that has not yet developed enough strength.

Always follow the instructions provided for the slab before driving or placing machinery on it.

Garage & Shed Concrete Slabs Throughout New Zealand

Concrete Services Direct can help arrange garage, shed and workshop concrete slab services across many parts of New Zealand.

Service areas include:

Northland
Auckland
Waikato
Gisborne
Bay of Plenty
Hawke’s Bay
Taranaki
Manawatu
Wairarapa
Wellington
Tasman
Marlborough
West Coast
North Canterbury
South Canterbury
Otago
Southland

Whether you’re building a residential garage, workshop, storage shed or larger vehicle building, tell us what you’re planning and provide any drawings or specifications you already have.

Find Garage & Shed Slab Contractors In Your Area

Frequently Asked Questions About Garage & Shed Concrete Slabs

What thickness should a garage concrete slab be?

The appropriate thickness depends on the garage design, vehicle loads, ground conditions, reinforcing and structural requirements.

A garage used for ordinary cars may have different requirements from one supporting heavy vehicles or machinery.

Does a garage slab need reinforcing?

Many garage slabs use reinforcing mesh or steel.

The required type and amount depend on the slab design and expected loads.

Can a concrete slab support a vehicle hoist?

Yes, if the slab is designed appropriately.

Vehicle hoists can create substantial concentrated loads, so the hoist manufacturer’s slab requirements should be checked before the concrete is poured.

What should I put under a shed concrete slab?

The slab will usually require a properly prepared and compacted base.

The exact preparation depends on the existing ground conditions and building design.

Can I put a shed directly on a concrete slab?

Yes, many sheds and workshops are constructed directly on concrete slabs.

The building’s anchoring and foundation requirements should be considered when designing the slab.

Do I need a foundation as well as a garage slab?

Sometimes the slab and foundations form part of one integrated concrete system.

The building plans or structural design should show the required foundation arrangement.

Can you pour a garage slab before the building arrives?

Yes, this is common, particularly for prefabricated garages and sheds.

However, the slab needs to match the building dimensions, anchoring requirements and floor levels accurately.

Can a garage slab be polished?

Yes.

If polished concrete is planned as the finished floor, this should ideally be established before the slab is poured so the concrete and finishing can be managed appropriately.

Can I coat a garage concrete floor?

Yes.

Garage slabs can be coated with suitable floor systems once the concrete has cured and been prepared according to the coating manufacturer’s requirements.

Can an existing garage slab be extended?

In many cases, yes.

The connection between the old and new slabs and any structural requirements need to be considered.

Can a cracked garage slab be repaired?

Some cracks can be repaired, but the cause of the cracking matters.

Significant settlement or structural movement may require further assessment before a repair solution is chosen.

Do shed slabs need drainage?

This depends on the building and how it will be used.

Garages, workshops and utility sheds may benefit from planned drainage or floor falls, particularly where water or vehicles are involved.

Do I need plans for a garage slab quote?

Plans are highly useful for structural garages, workshops and larger sheds.

They can show the dimensions, foundations, reinforcement and anchor details needed for accurate pricing.

How much does a garage or shed slab cost?

Pricing depends on size, ground preparation, slab thickness, reinforcement, concrete volume, foundations, access and finishing.

A quote based on the specific building and site will provide the best indication.

Get A Quote for Your Garage or Shed Concrete Slab

Whether you’re building a new garage, workshop, garden shed, vehicle storage building or larger outbuilding, the concrete slab needs to suit the structure and how it will be used.

Tell us where the project is located, the building dimensions and what you plan to use the space for. If you already have plans or a slab specification, include those details as well.