10 February 2025 • 8 min read

Building Consent Requirements for Excavation in Nelson & Tasman: Complete 2025 Guide

Kiwi Excavations Team

Author

building consent excavation nelson excavation consent tasman nelson excavation tasman excavation building consent excavation excavation permits nelson city council tasman district council

Building Consent Requirements for Excavation in Nelson & Tasman: Complete 2025 Guide

Navigating building consent requirements for excavation work in the Nelson-Tasman region can be confusing, especially with two different councils managing the area. Whether you’re planning foundation work in Nelson City or site preparation in Tasman District, understanding the consent requirements is crucial for your project’s success.

The cost of non-compliance extends far beyond initial consent fees. Projects starting without proper consents face immediate stop-work orders, costly delays of 4-8 weeks, additional consultant fees, and potential legal action. With both councils experiencing significant processing delays due to staff shortages, getting your consent application right the first time is more critical than ever.

This comprehensive guide provides practical, up-to-date information on excavation consent requirements, application processes, and costs for both Nelson City Council and Tasman District Council. We’ll help you determine when you need consent, what documentation is required, and how to avoid common mistakes that delay projects.

Nelson City Council vs Tasman District Council Key Differences

The Nelson-Tasman region operates under two separate territorial authorities, each with distinct processes and requirements. Nelson City Council covers Nelson city and immediate surrounds, while Tasman District Council manages the broader rural and coastal areas including Richmond, Motueka, Takaka, and Murchison.

Processing Differences:

Nelson City Council: Uses Simpli online portal system, typically processes consents within 20 working days (currently experiencing 25-30 day delays)
Tasman District Council: Manual and online application options, similar 20-day statutory timeframe with current delays extending to 35+ days

Fee Structure Variations:

Nelson: Residential building consent fees start at $3,900 for single-storey dwellings
Tasman: Equivalent consents start at $3,294, generally 15-20% lower than Nelson

Technical Requirements: Both councils require compliance with the New Zealand Building Code, but interpretation and additional requirements can vary. Nelson tends to require more detailed engineering input for complex excavations, while Tasman may have additional environmental considerations for rural properties.

Understanding the difference between building consent and resource consent is essential, as excavation projects often trigger both requirements.

Building Consent (administered by territorial authorities):

Required for construction, alteration, or removal of buildings
Covers structural integrity, safety, and building code compliance
Relevant for foundation excavation, retaining walls, and site preparation affecting buildings

Resource Consent (administered by regional councils):

Required for activities affecting the environment
Covers land use, subdivision, water take, and discharge permits
May be needed for large-scale earthworks, stream diversions, or contaminated soil removal

For most residential excavation projects, building consent is the primary requirement. However, resource consent may also be needed for environmental considerations.

Building consent is required for excavation work when it:

Forms part of building construction or alteration
Affects structural integrity of existing buildings
Creates potential safety hazards
Involves specialist engineering requirements

Common Triggers:

Foundation excavation for new buildings (any depth)
Retaining wall excavation supporting loads or exceeding height thresholds
Basement construction requiring structural excavation
Pool excavation for permanent swimming pools
Site preparation affecting building stability or drainage

Volume Thresholds: While there’s no specific cubic meter trigger for building consent, large-scale earthworks (typically 500+ cubic meters) may require additional resource consent considerations.

Timeline Expectations and Current Processing Delays

Statutory Timeframes:

Standard processing: 20 working days from complete application
Complex applications: Up to 60 working days with extensions
Fast-track options: Available for simple, compliant applications

Current Reality (2025): Both councils are experiencing significant delays due to staff shortages and increased application volumes:

Nelson City Council: 25-35 working days typical
Tasman District Council: 30-40 working days typical
Peak season (November-March): Additional 5-10 day delays common

Planning Recommendations:

Submit applications 8-10 weeks before intended construction start
Consider off-peak submission timing (April-August) for faster processing
Ensure complete applications to avoid request-for-information delays

Foundation Excavation for New Buildings

All foundation excavation requires building consent, regardless of depth or building size. This includes:

Residential Projects:

House foundations (full basement to simple concrete pad)
Garage and outbuilding foundations
Sleepout and granny flat foundations
Workshop and storage building foundations

Commercial Projects:

Office and retail building foundations
Industrial facility foundations
Agricultural building foundations (depending on classification)

Documentation Requirements:

Structural engineering calculations
Geotechnical assessment (for sites with challenging soil conditions)
Drainage and foundation waterproofing details
Site survey and levels plan

Retaining Wall Excavation

Retaining wall excavation requires building consent when walls exceed specific thresholds or support additional loads.

Consent Required For:

Walls retaining more than 1.5 meters depth of ground
Walls supporting driveways, buildings, or other surcharge loads
Walls within 1.5 times their height from buildings or boundaries
Engineered wall systems regardless of height

Nelson-specific requirements include:

Detailed engineering design for walls over 1.0m in residential areas
Additional safety factors for walls near property boundaries
Specific drainage and foundation requirements

Common Retaining Wall Scenarios Requiring Consent:

Driveway support walls (any height with vehicle loading)
Basement retaining walls
Terraced landscaping with multiple wall systems
Pool surrounds with integrated retaining elements

Site Preparation Affecting Structural Integrity

Building consent is required for site preparation work that could affect the structural integrity of existing or proposed buildings.

Consent-Required Scenarios:

Excavation within the zone of influence of existing foundations
Site cuts affecting slope stability near buildings
Excavation altering natural drainage patterns around structures
Ground modification affecting bearing capacity

Zone of Influence Guidelines:

Shallow foundations: 45-degree angle from foundation base
Deep foundations: Professional engineering assessment required
Existing retaining walls: 1.5 times wall height horizontally

Pool Excavation Requirements

Swimming pool excavation requires building consent for pools capable of holding 400mm or more of water depth.

Consent Covers:

Excavation and earthworks
Pool structure and installation
Safety barriers and fencing (F9 compliance)
Associated drainage and services

Special Considerations:

Above-ground pools may still require consent if excavation is involved
Spa pools and hot tubs follow similar requirements
Pool equipment buildings require separate building consent

Associated Requirements: Pool projects often trigger additional consent needs:

Resource consent for large excavations or water take
Electrical work notifications
Plumbing and drainage approvals

Learn more about pool excavation costs and planning in our upcoming comprehensive pool excavation guide.

Basement and Underground Space Excavation

Basement construction involves complex excavation requiring detailed engineering and multiple consent considerations.

Building Consent Requirements:

Structural design for excavation support
Waterproofing and drainage systems
Access and egress compliance
Ventilation and services installation

Specialized Assessments:

Geotechnical investigation and foundation design
Groundwater assessment and dewatering requirements
Existing building impact assessment
Construction methodology and safety plans

Common Challenges:

High groundwater levels in coastal areas
Rock excavation requirements
Existing utility services conflicts
Temporary works design and certification

Schedule 1 Exemptions for Excavation

Not all excavation work requires building consent. Schedule 1 of the Building Act lists specific exemptions that allow work to proceed without consent.

Minor Earthworks Within Approved Building Footprint

Exempt Work Includes:

Ground preparation within consented building footprint
Service trenching for consented buildings
Minor level adjustments for compliance with approved plans
Temporary excavation for construction access

Limitations:

Must not affect structural design assumptions
Cannot alter approved drainage patterns
Limited to work specified in existing building consent
May not extend beyond approved building envelope

Landscaping and Garden Preparation

Generally Exempt:

Garden bed preparation and planting
Decorative landscaping features
Minor grading for lawn and garden areas
Ornamental pond construction (under 400mm depth)

Important Limitations:

Cannot affect building stability or drainage
Must not create retaining wall requirements
Cannot impact existing building foundations
Limited depth restrictions apply near services

Maintenance and Repair Work

Exempt Maintenance Includes:

Existing driveway and path repairs
Drainage maintenance within existing alignments
Foundation maintenance not altering structure
Utility repair work within existing easements

Repair vs Replacement:

Like-for-like replacement generally exempt
Structural modifications require consent
Capacity increases may trigger consent requirements

Common Misconceptions About “Small” Projects

Myths That Cost Property Owners:

“Small excavations don’t need consent”

Size alone doesn’t determine consent requirements
Function and impact matter more than volume
Proximity to buildings and services crucial

“Rural properties have different rules”

Same building consent requirements apply
Additional resource consent considerations may apply
Distance from neighbors doesn’t exempt consent requirements

“DIY work doesn’t need consent”

Consent requirements independent of who does the work
Professional contractor requirements separate from consent needs
Insurance and liability issues with non-consented work

“Temporary excavation is always exempt”

Temporary nature doesn’t automatically exempt consent
Construction methodology may still require approval
Restoration requirements often specified

For detailed guidance on contractor selection and project planning, see our comprehensive contractor selection guide.

Application Process & Documentation

Required Forms and Supporting Documents

Nelson City Council Applications:

Project Information Memorandum (PIM) for complex sites
Building consent application form (BC1)
Detailed excavation and construction plans
Professional engineering documentation where required

Building Performance Standards Compliance: All applications must demonstrate compliance with relevant Building Code clauses:

B1: Structure (foundation and retaining wall design)
B2: Durability (material specifications and protection)
E1: Surface water management (drainage integration)
E2: External moisture (waterproofing systems)

Documentation Quality Standards:

Plans drawn to scale with full dimensions
Cross-sections showing excavation depths and slopes
Existing building locations and proximity details
Service locations and protection measures

Geotechnical Report Requirements

When Geotechnical Reports Are Required:

Sites with known challenging soil conditions
Excavations exceeding 3 meters depth
Retaining walls supporting significant loads
Buildings on sloping sites with cut/fill requirements

Nelson-Tasman Soil Considerations: The region’s diverse geology creates specific challenges:

Clay soils: Expansion and shrinkage considerations
Rock outcropping: Excavation methodology and vibration management
Coastal areas: Groundwater and soil stability issues
Hill sites: Slope stability and cut/fill design

Report Content Requirements:

Site investigation methodology and findings
Bearing capacity recommendations
Foundation design parameters
Excavation slope stability assessment
Drainage and waterproofing recommendations

Professional Engineer Involvement

When Engineering Input Is Required:

Retaining walls over 1.5 meters height
Foundation systems on challenging sites
Excavations affecting existing structures
Commercial and multi-story residential projects

Engineer Responsibilities:

Structural design and calculations
Construction methodology review
Producer statements (PS1, PS4) as required
Site inspection and certification

Selecting Qualified Engineers:

CPENG (Chartered Professional Engineer) registration
Local experience with Nelson-Tasman soil conditions
Specialist knowledge in relevant excavation and foundation types

Nelson City Council - Simpli Portal:

Online application submission and tracking
Document upload and revision management
Automated fee calculation and payment
Real-time processing status updates

Application Tips:

Prepare all documents before starting online application
Use clear, descriptive file names for uploads
Monitor application status for council requests for information
Respond promptly to avoid processing delays

Building Performance Portal Integration:

Connects local council systems with national databases
Enables compliance checking and verification
Provides access to technical guidance and standards

Cost Breakdown & Budgeting

Nelson vs Tasman Fee Structures

Nelson City Council Fees (2025):

Basic excavation consent: $1,200-3,900 depending on complexity
Residential foundation: $2,400-4,800 typical range
Commercial excavation: $4,900-15,000+ based on project value
Amendment fees: $450-1,200 for significant changes

Tasman District Council Fees (2025):

Basic excavation consent: $950-3,200 (approximately 15-20% lower than Nelson)
Residential foundation: $1,950-3,900 typical range
Commercial excavation: $3,900-12,000+ based on project value
Amendment fees: $350-950 for changes

Fee Calculation Methods: Both councils use time-based charging:

Standard rates: $180-220 per hour for processing officer time
Complex projects: Senior engineer review at $250-300 per hour
Specialist input: External consultant fees passed through to applicant

Additional Costs and Specialist Reports

Geotechnical Investigation:

Residential sites: $1,500-4,500 for standard soil investigation
Commercial sites: $3,500-12,000+ for comprehensive geotechnical study
Challenging sites: Additional testing may add $2,000-8,000

Professional Engineering:

Foundation design: $2,500-8,500 for residential projects
Retaining wall design: $1,800-6,500 depending on complexity
Construction monitoring: $150-250 per site visit
Producer statements: $500-1,500 per PS1/PS4

Survey and Drafting:

Site survey: $850-2,500 for residential sites
Construction drawings: $1,200-4,500 for excavation plans
As-built documentation: $650-1,850 for completion records

Timeline Impact on Project Budgets

Delay Costs:

Equipment mobilization: $500-1,500 for rescheduling machinery
Material storage: $200-800 per month for delayed material deliveries
Construction crew: $300-1,200 per day for idle time
Project financing: Interest costs on construction loans during delays

Seasonal Cost Variations:

Winter work premiums: 15-25% increase for difficult ground conditions
Peak season scheduling: 10-15% premium during November-March
Weather delays: Insurance and contingency requirements

Value Engineering Opportunities:

Off-peak applications: Faster processing during April-August
Complete submissions: Avoiding RFI delays saves 2-4 weeks
Professional preparation: Upfront engineering investment reduces delays

For detailed excavation cost breakdowns and budgeting guidance, see our comprehensive excavation pricing guide.

Common Mistakes to Avoid

The most costly mistake property owners make is beginning excavation work before receiving building consent approval.

Immediate Consequences:

Stop-work orders issued within 24-48 hours of discovery
Enforcement action including fines up to $200,000
Demolition orders requiring removal of non-compliant work
Insurance invalidation for work performed without consent

Long-term Impacts:

Consent process restart adding 6-12 weeks to project timeline
Additional design costs to incorporate existing work
Relationship damage with councils affecting future applications
Sale complications when non-consented work discovered

Incomplete Applications Causing Delays

Common Documentation Gaps:

Missing site surveys or outdated boundary information
Inadequate engineering details for structural elements
Incomplete drainage plans and stormwater management
Unclear construction methodology and temporary works details

Prevention Strategies:

Pre-application meetings with council planning staff
Professional preparation using qualified consultants
Checklist verification before submission
Peer review of application completeness

Misunderstanding Exemption Criteria

Dangerous Assumptions:

“Small” projects don’t need consent (size doesn’t determine exemption)
“Temporary” work is always exempt (function matters more than duration)
“Rural properties have different rules” (same building consent requirements apply)
“DIY work doesn’t need consent” (consent independent of who performs work)

Verification Process:

Council pre-application enquiry for borderline cases
Professional consultation with building consent advisors
Written confirmation of exemption status before proceeding

For comprehensive guidance on avoiding project delays and cost overruns, see our seasonal excavation planning guide and contractor selection criteria.

Ready to Start Your Excavation Project?

Understanding building consent requirements is just the first step in successful excavation project planning. At Kiwi Excavations, we work with property owners and builders throughout the Nelson-Tasman region to ensure projects proceed smoothly from consent through completion.

Free Project Consultation

Our experienced team can help you:

Determine consent requirements for your specific project
Prepare accurate documentation for council submissions
Navigate the application process efficiently
Plan project timing to minimize delays and costs

Schedule your free 15-minute consultation to discuss your excavation project requirements with our licensed professionals.

Get our comprehensive “Building Consent Checklist for Excavation Projects” - a detailed guide covering all documentation requirements, key considerations, and common pitfalls to avoid.

Download Free Checklist

About Kiwi Excavations

Serving the Nelson-Tasman region for over [years], we specialize in residential and commercial excavation, foundation preparation, retaining walls, and site development. Our team holds current building licenses, safety certifications, and comprehensive insurance coverage.

Contact Information:

Phone: 027 KIWIDIG (027 549 4344)
Email: [email protected]
Service Areas: Nelson City, Tasman District, Richmond, Motueka

Related Reading:

This guide is updated regularly to reflect current building consent requirements and council procedures. For the most current information, always verify requirements directly with Nelson City Council or Tasman District Council before proceeding with your project.

Get Your Free Quote