Garage conversion cost

Costs vary a lot depending on your property, consent, and intended use. This page explains typical cost drivers and ranges so you can plan with realistic expectations.

What a compliant conversion actually means

A compliant garage conversion is designed to meet building code requirements for habitability, insulation, fire safety, and access. This typically means proper insulation, ventilation, moisture management, and (where applicable) fire-rated construction. We assess your garage and advise on what's typically required so you can understand the cost implications.

Who this is for

Homeowners and investors who want clarity on costs before committing. We provide realistic ranges and explain what drives costs so you can decide if conversion makes sense for your situation and budget.

Who this is not for

If you want the cheapest option or want to avoid consent, we're probably not the right fit. We build habitable, compliant spaces that meet building code. Where conversion costs outweigh benefits, we'll tell you.

Typical cost drivers

Conversion costs are driven by several factors:

Consent and compliance

• Building consent fees (typically $2,000–$5,000)
• Engineering reports and structural assessments (if required)
• Council processing time and any additional requirements
• Resource consent (if required for change of use or intensity)

Structural work

• Floor upgrades (if needed for habitable use)
• Wall structure (if reinforcement is required)
• Roof structure (if additional support is needed)
• Foundation work (if required)

Insulation and fire safety

• Wall insulation (typically required for habitable use)
• Ceiling insulation (upgrade to meet code)
• Floor insulation (where applicable)
• Fire-rated construction (walls, ceilings, doors where required)
• Means of escape (doors, windows, travel distances)

Moisture and ventilation

• Cladding and weatherproofing
• Underfloor ventilation
• Roof space ventilation
• Vapour barriers and moisture management

Intended use

• Sleeping accommodation (bedroom, rental, Airbnb) often has higher requirements than office use
• Separate dwelling vs part of main house affects fire separation needs
• Rental readiness may require additional compliance items

Garage type and condition

• Attached vs detached affects fire separation requirements
• Existing condition (structure, moisture, ventilation)
• Access for construction

Typical cost ranges

These are ranges, not guarantees. Every property is different; we assess on-site and provide realistic estimates based on your situation.

• Basic conversion (office/studio, minimal structural work): $15,000–$35,000
• Standard conversion (bedroom/rental, typical consent requirements): $30,000–$60,000
• Complex conversion (significant structural work, fire separation, separate dwelling): $50,000–$100,000+

These ranges include consent, design, and construction but exclude furniture, fittings, and any additional work outside the conversion scope.

What we don't do

We don't give fixed-price quotes without assessing your property. We don't do cosmetic-only upgrades that ignore building code. We don't guarantee that every garage can be converted within a specific budget. Every property is different; we assess on-site.

Timeline expectations

Timelines affect costs indirectly (longer timelines may mean higher holding costs). Typical timelines:

• Assessment and design: 2–4 weeks
• Building consent: 4–8 weeks
• Construction: 4–12 weeks

These are ranges. We provide realistic timelines based on your situation.

Our process

We start with a feasibility assessment to clarify consent risk, key cost drivers, and whether conversion is the right option for your property. If it makes sense, we handle all compliance, do all building ourselves, and manage the job from start to finish. For details, see our our process page.

Frequently asked questions

How much does a garage conversion cost?

Costs vary significantly based on consent requirements, structural work, insulation, fire safety, and intended use. Typical ranges: basic conversion $15,000–$35,000, standard conversion $30,000–$60,000, complex conversion $50,000–$100,000+. We assess your situation and provide realistic estimates.

What's included in garage conversion costs?

Typically: building consent fees, design and engineering, structural work, insulation, fire safety, moisture management, ventilation, and construction. Excludes furniture, fittings, and work outside the conversion scope. We provide detailed estimates based on your situation.

Do I need building consent, and how much does it cost?

Habitable conversions typically require building consent. Consent fees are typically $2,000–$5,000, plus any engineering reports or additional council requirements. See our garage conversion consent page for more detail.

What affects garage conversion costs the most?

Key drivers: structural work needed, insulation and fire safety requirements, intended use (sleeping vs office), garage type (attached vs detached), and existing condition. We assess your situation and explain what typically applies.

Can I get a fixed-price quote?

We provide realistic estimates based on your situation, but costs can vary during consent and construction. We assess on-site and explain cost drivers so you can plan with clarity. Every property is different.

Is a garage conversion cheaper than an extension?

It depends on your situation. Garage conversions may be more cost-effective if the structure is suitable, but they still require consent and building code compliance. See our comparison pages for more detail (coming soon).

Related guides

• Garage conversions Canterbury, our main service area
• Garage conversions Christchurch, serving Christchurch
• Garage conversion consent, consent requirements and costs
• Garage conversion building code, code requirements that affect costs
• Our process, how we work and assess costs
• Contact, request a feasibility assessment