Planning a concrete slab in Brisbane? Whether it is for a new shed, garage, granny flat, or house extension, the cost depends on the slab type, thickness, size, and site conditions. This guide gives you realistic 2026 Brisbane prices so you can budget accurately.
Quick Cost Summary
| Slab Type | Cost per m2 | Typical Total Cost |
|---|---|---|
| Shed slab (100mm) | $65 - $90 | $2,000 - $4,500 |
| Garage slab (100mm) | $75 - $100 | $3,000 - $6,000 |
| Patio slab (100mm) | $80 - $110 | $2,500 - $5,500 |
| House slab (waffle pod) | $110 - $160 | $15,000 - $35,000 |
| Granny flat slab | $100 - $150 | $6,000 - $12,000 |
These prices include concrete supply, labour, formwork, mesh reinforcement, and basic site preparation. They do not include excavation of problem soils, rock removal, or engineering.
What Affects Slab Cost?
1. Slab Thickness
Thicker slabs use more concrete and reinforcement:
| Thickness | Typical Use | Cost Impact |
|---|---|---|
| 75mm | Light foot traffic paths | Lowest cost |
| 100mm | Sheds, patios, garages | Standard residential |
| 150mm | Heavy vehicle areas | +30-40% over 100mm |
| 200mm+ | Commercial, house slabs | +50-70% over 100mm |
2. Concrete Strength (MPa)
Higher strength concrete costs more per cubic metre:
| Strength | Use | Cost per m3 |
|---|---|---|
| 20 MPa | Paths, light-duty slabs | $220 - $260 |
| 25 MPa | Standard residential | $240 - $280 |
| 32 MPa | Driveways, heavy loads | $260 - $310 |
| 40 MPa | Structural, commercial | $290 - $340 |
3. Reinforcement
Standard mesh (SL72 or SL82) is included in most quotes. If your slab needs rebar (N12 or N16 bars), expect an additional $15-30 per m2.
4. Site Conditions
Brisbane-specific factors that add cost:
- Reactive clay soils (common in western suburbs like Ipswich, Springfield): May need deeper footings or a waffle pod design. Adds $20-40 per m2.
- Sloping sites: Requires more formwork and potentially a suspended slab. Can double the cost.
- Rock: If excavation hits rock, removal costs $80-150 per m3.
- Poor access: If a concrete truck cannot reach the site, a concrete pump is needed ($800-1,500 per pour).
5. Finish Type
The surface finish affects both appearance and cost:
| Finish | Additional Cost per m2 | Look |
|---|---|---|
| Broom finish | Included | Standard textured |
| Steel trowel | $5 - $10 | Smooth, polished look |
| Exposed aggregate | $30 - $50 | Decorative stone surface |
| Coloured concrete | $15 - $25 | Integral colour throughout |
| Stamped/stencilled | $40 - $70 | Pattern imprint |
Example Costings
6x3m Shed Slab (18m2)
- 100mm thick, 25 MPa, broom finish
- SL72 mesh reinforcement
- Flat site with good access
- Estimated cost: $1,400 - $1,800
Double Garage Slab (36m2)
- 100mm thick, 32 MPa, broom finish
- SL82 mesh reinforcement
- Flat site with good access
- Estimated cost: $2,800 - $3,600
Outdoor Entertaining Area (40m2)
- 100mm thick, 25 MPa, exposed aggregate finish
- SL72 mesh reinforcement
- Flat site, good access
- Estimated cost: $4,400 - $6,000
Granny Flat Slab (60m2)
- Waffle pod design, 25 MPa
- Engineering design included
- Standard residential site
- Estimated cost: $6,000 - $9,000
How to Get an Accurate Quote
Online calculators give you a ballpark, but every site is different. For an accurate quote, we need to:
- Visit your property and assess the site
- Check soil conditions and slope
- Confirm access for concrete trucks
- Discuss your requirements (thickness, finish, use)
- Provide a written quote with all inclusions listed
Tips to Save Money
- Combine projects: Getting a driveway and shed slab done at the same time saves on mobilisation costs.
- Standard finishes: Broom finish is the most affordable. Exposed aggregate adds $30-50 per m2.
- Good preparation: Clear the site yourself (remove vegetation, old concrete) to reduce labour costs.
- Right thickness: Do not over-engineer. A shed slab does not need to be 150mm thick.
Get a Free Quote
Concrete Concepts Group pours slabs across Brisbane every week. We provide free on-site quotes with clear, itemised pricing. No hidden costs.
Call us or request a quote online to get started.
Related Articles
Learn why preparation matters in our Concrete Slab Preparation Guide. Planning a shed? Read our Concrete Shed Slabs Brisbane Guide. Understand thickness requirements in our How Thick Should a Concrete Slab Be? guide. Learn about curing times in our How Long Does Concrete Take to Cure? Brisbane climate guide.
Use our Concrete Cost Calculator for an instant estimate or request a free on-site quote.
Get a Free Quote for Your Project
No obligation — we'll call you within 24 hours to discuss your needs.
Concrete Concepts Group
QBCC Licensed (#15299707) concreting professionals serving Brisbane and all surrounding areas. Over 100 projects completed with a 5-star reputation.
Homeowner's Guide to Concreting
13-page guide covering finishes, costs, council requirements, and maintenance tips for Brisbane homeowners.
Download Free
