If you own a sloping property in Melbourne, you’ve probably discovered that landscaping quotes come in significantly higher than for flat sites. This guide explains why challenging sites need professional landscape design and helps you budget realistically for your project.
Why Steep Blocks Cost More
Several factors compound to increase costs on sloping sites:
1. Retaining Walls
The most significant cost difference. Creating usable flat areas requires retaining walls to hold back soil. Walls are expensive to build, especially when engineering is required.
2. Earthworks
Moving soil to create level areas involves excavation, sometimes importing or exporting soil, and compaction. Heavy equipment access adds complexity.
3. Drainage Infrastructure
Water management is critical on slopes. Comprehensive drainage systems behind walls, surface water management and connections to stormwater add significant cost.
4. Engineering Requirements
Walls over 500mm typically need engineering certification. Complex sites may need geotechnical assessment. This adds professional fees and ensures structural safety.
5. Construction Difficulty
Difficult access, manual material handling, and safety considerations extend construction time and increase labour costs.
Cost Components Breakdown
Retaining Walls
Retaining wall costs vary dramatically by type, height and site conditions:
| Wall Type | Cost per Linear Metre | Best For |
|---|---|---|
| Timber sleepers (under 1m) | $300-$500 | Budget projects, low walls |
| Concrete block (to 1.5m) | $500-$800 | Most residential applications |
| Stone-faced concrete | $800-$1,200 | Premium appearance |
| Natural stone | $1,000-$1,500+ | High-end projects |
| Engineered walls (over 1.5m) | $1,200-$2,500+ | Significant level changes |
A typical steep block might have 30-60 linear metres of retaining walls across multiple levels.
Earthworks
Earthworks costs depend on:
- Volume of soil to move
- Whether soil is cut to fill elsewhere or exported
- Equipment access
- Soil conditions (rock significantly increases costs)
Budget ranges:
- Minor reshaping: $3,000-$8,000
- Moderate terracing: $10,000-$30,000
- Significant level changes: $30,000-$80,000+
Drainage
Comprehensive drainage is non-negotiable on steep sites:
- Agricultural drains behind walls: $80-$150 per linear metre
- Surface drainage channels: $150-$300 per linear metre
- Stormwater connection: $1,500-$4,000
- Rain gardens/detention: $3,000-$8,000
Total drainage budget: 10-15% of project cost or $5,000-$20,000 minimum
Professional Fees
- Survey: $800-$2,000 depending on complexity
- Geotechnical report: $1,500-$4,000 if required
- Structural engineering: $2,000-$8,000 for wall design
- Landscape design: $4,000-$15,000 depending on scope
Steps and Access
Creating access through your garden:
- Timber steps: $300-$500 per step
- Stone/masonry steps: $500-$800 per step
- Concrete steps: $400-$600 per step
- Handrails: $200-$400 per linear metre
A steep garden might need 30-50 steps across various locations.
Total Project Budgets
Small Steep Block (under 200sqm)
- Simple terracing approach
- 1-2 retaining walls
- Basic drainage
Budget: $40,000-$80,000
Medium Steep Block (200-400sqm)
- Multiple terrace levels
- Several retaining walls
- Comprehensive drainage
- Steps and pathways
Budget: $80,000-$150,000
Large Steep Block (400sqm+)
- Extensive terracing
- Major retaining walls, possibly engineered
- Complex drainage system
- Significant steps and pathways
- Premium finishes
Budget: $150,000-$300,000+
Strategies to Manage Costs
1. Work with the Slope
Not every area needs to be flat. Embrace sloping lawns, planted embankments and natural contours where usable flat space isn’t essential.
2. Prioritise Key Areas
Invest in properly engineered terracing for main living areas. Use simpler, lower-cost solutions for secondary spaces.
3. Stage the Project
Design the whole site but build in stages. This spreads costs and allows refinement as you use the space.
4. Choose Wall Materials Wisely
Timber sleepers for hidden walls, save stone facing for visible areas. Block walls can be rendered to improve appearance affordably.
5. Get Engineering Right First Time
Cutting corners on engineering leads to failure and expensive rectification. Do it properly initially.
6. Plan Drainage Comprehensively
Retrofit drainage is expensive and disruptive. Include comprehensive drainage in initial construction.
Getting Accurate Quotes
Steep block quotes are notoriously variable. Ensure quotes are comparable by:
Providing Clear Documentation
- Survey with levels
- Design drawings showing wall locations and heights
- Material specifications
- Drainage requirements
Ensuring Quotes Include
- All engineering and certification
- Complete drainage specification
- Specific wall heights and lengths
- Access and site management
- Establishment period work
Checking Qualifications
- Verify landscaper experience with steep sites
- Confirm engineering credentials
- Check insurance coverage for the work scope
- Request references from similar projects
Hidden Costs to Anticipate
Rock Excavation
Hitting rock during earthworks can double or triple excavation costs. Geotechnical assessment helps predict this.
Imported Soil
If cut material isn’t suitable for fill, importing quality soil adds significant cost.
Extended Timelines
Steep blocks take longer to build. Extended supervision, hire periods and weather delays add up.
Access Track Restoration
Temporary access tracks need restoration after construction.
Establishment Care
Young plantings on slopes need more attention during establishment.
Is It Worth the Investment?
Despite higher costs, well-designed steep block landscapes often deliver excellent value:
- Views and aspect that flat blocks can’t match
- Dramatic garden rooms at different levels
- Unique character and interest
- Often lower land cost relative to flat blocks
- Good capital growth when done well
The key is realistic budgeting and quality execution. Underspending on a steep block leads to poor outcomes. Investing appropriately creates something special.
Next Steps
If you’re facing a steep block project, start with professional advice:
- Get a proper survey with levels
- Consult a landscape designer experienced with slopes
- Understand engineering requirements early
- Budget realistically including contingency
Contact us to discuss your steep block project and understand what’s achievable within your budget.
