Cost guide · Wellington

Second-Storey Addition cost in Wellington (2026)

Typical Wellington range

$212,000 – $509,000

Most Wellington projects land around $292,000 – $371,000. Prices run around the national average, with site costs the swing factor.

Why Wellington differs

Wellington's Very High and Extra High wind zones and seismic foundations add bracing and engineering most flat sites elsewhere don't need.

Usually included

New floor structure
Framing, cladding & roof
Stairs
New rooms fitted out
Scaffolding

Usually excluded

Reworking the entire ground floor
Temporary accommodation
Landscaping
Consent & development contributions

Usually needs a building consent

A second storey is significant structural work and requires a building consent, with structural engineering. Read the consent rules →

See 370 Builders on the register in Wellington

Questions to ask before you sign

Can the existing foundations and framing take a second storey — who confirms that?
How will the house be protected from weather during the build?
What's the realistic timeline and payment schedule?

Wellington second-storey addition: common questions

How much does it cost to add a second storey in NZ?: A second-storey addition typically costs $200,000–$450,000+, around $3,500–$5,500 per m² — roughly 10–20% more than an equivalent ground-floor extension due to structural reinforcement and access.
Do I need to move out during a second-storey addition?: Usually for part of it — removing the existing roof exposes the house to weather, so most homeowners move out during the riskiest weeks.

Before you pay anyone, check who they are.

Check the company that quoted you: company status, registration and what's on the public record, from the official NZ sources.

Check a builder

Actually starting this build? Keep watch on your builder for the whole build →

Figures are 2026 estimates for guidance only, not a quote. Actual cost depends on your site, spec and the company you choose. Always get written quotes and check the company on the public record before you pay a deposit.