Existing building focus
Retrofit and upgrade inside buildings that are already there: old structure, live tenancies, services in the way, and make-good that has to look right when the work is done.
Seismic upgrade · Existing buildings · New Zealand
Seismic upgrade building NZ: strengthening what is already there
A seismic upgrade building NZ owners and councils are asking about is not a new design from the ground up. It is the work of taking a CPEng structural engineer's upgrade scheme and integrating it into an existing building: resolving clashes between old and new structure, documenting make-good, and preparing consent drawings, often while a reroof, code upgrade or fitout is happening at the same time.
What you get from us
Integration and documentation, not structural engineering
The engineer designs the upgrade. The designer makes it fit the building that is already on site: where new steel meets old timber or concrete, what gets propped during construction, how linings and roofs close back up, and what a council needs to see on paper before work starts. That is applied design work, not a claim to be the structural engineer on the job.
Engineer-led structure
All structural upgrade design and sign-off stays with a CPEng structural engineer. We integrate their scheme into buildable, consent-ready documentation without overstating what the designer's role is.
Coordination with other work
Seismic upgrades often run alongside reroof, code upgrade or fitout. We map clashes between new bracing and existing roofs, linings and services so one programme does not undo another.
What does a seismic upgrade on an existing building involve?
It starts with an engineer's assessment and upgrade design: new bracing walls, steel frames, foundation work or connection upgrades sized for the building's seismic zone and Importance Level. From there the building designer documents how that scheme sits inside the existing structure. That means plans and sections showing old and new members meeting, demolition and propping notes, make-good to linings and roofs, and coordination with any reroof, code upgrade or fitout running on the same programme.
On commercial building design and industrial building design projects we usually work from a blank page. Seismic upgrade work is the opposite: the building is already there, tenants may still be operating, and the documentation has to show exactly how the upgrade lands without pretending the original structure was designed for it.
Who designs the structure and who integrates it?
All structural upgrade design is done and signed off by a CPEng structural engineer. That includes member sizing, connection design, bracing layouts and the producer statements a building consent authority expects. Marsco does not take that role and does not present the designer as the engineer on the job.
What we do is integrate the engineer's scheme into buildable documentation: clash detection between new steel and existing roofs or services, make-good details that finish cleanly, sequencing notes where propping or partial demolition is needed, and the consent drawings that tie the upgrade back to the rest of the building. If drawings from an earlier project need correction before the upgrade can proceed, that sits alongside our building design remediation work.
Why do seismic upgrades often run with reroof or fitout work?
Opening a roof once to add bracing or upgrade connections is expensive if you close it up and open it again six months later for a reroof. Owners and tenants often prefer one programme: engineer the seismic upgrade, replace the roof or reclad while structure is exposed, and complete make-good and fitout in a single pass. The designer's job is to map those overlaps before consent: where new bracing conflicts with roof purlins, how fire or accessibility upgrades interact with structural work, and what the finished building looks like when every trade has been through.
The same coordination applies to earthquake strengthening building NZ owners commission on warehouses and light industrial premises. A building seismic retrofit NZ councils will accept needs documentation that shows the upgrade, the envelope work and any tenant fitout as one coherent consent set, not three separate projects fighting each other on site.
How is retrofit different from greenfield seismic design?
Greenfield seismic design chooses a structural system for a building that does not exist yet: portal frames, braced bays, foundations sized from geotechnical input, and envelopes designed around that structure from the first sketch. Retrofit works inside what a previous designer and builder left behind: odd grids, services cast into walls, foundations that were never sized for current Importance Level rules, and finishes that cannot simply be stripped away.
This page is about that retrofit and upgrade work on existing buildings. Broader seismic design for new construction and insulated panel lateral loading is covered elsewhere on the site. If your project is an existing commercial or industrial building that needs strengthening integrated into workable drawings, that is what this service is for.
Common questions
Seismic upgrades: your questions
- What is a seismic upgrade for an existing building in New Zealand?
- A seismic upgrade is the work of strengthening a building that is already built so it performs better in an earthquake. A CPEng structural engineer designs the upgrade system: new bracing, foundations, connections or structural elements sized for the building's Importance Level and seismic zone. The building designer then integrates that engineering into the existing structure, documents how old and new parts meet, resolves clashes with services and finishes, and prepares the consent drawings. It is retrofit work on a standing building, not seismic design for a new one.
- Who does what on a seismic upgrade project?
- The structural engineer designs and signs off all structural work: the upgrade scheme, member sizes, connections and the producer statements a council expects. The LBP Design Class building designer coordinates the documentation: plans and sections showing where new structure sits against the old, make-good details, coordination with reroof or fitout, and the building consent application. Installers and contractors build from those drawings. Marsco does not replace the engineer's structural role; we make the engineer's upgrade buildable and consent-ready inside an existing building.
- Can a seismic upgrade happen at the same time as a reroof or fitout?
- Often, yes, and that is frequently the most practical approach. A reroof exposes structure and lining that would otherwise need to be opened up again for bracing or connection work. A fitout or code upgrade can run on the same programme if the designer maps clashes early: where new steel meets an existing roof plane, how make-good finishes back to occupied areas, and what the tenant or owner needs to keep operating during construction. Coordinating all of that in one consent set is usually cheaper than sequential projects.
- How is seismic upgrade different from seismic design on a new building?
- New building seismic design starts from a blank structural system: the engineer and designer choose frames, walls and foundations for a building that does not exist yet. A seismic upgrade works inside constraints the original build created: existing foundations, odd column grids, services already routed through walls, tenants in place, and structure that was drawn to an older code. The designer's job is integration and documentation: showing how the upgrade connects to what is already there, what gets removed or propped, and what make-good the finished building needs. That is a different skill from greenfield seismic design.
- What types of buildings need seismic upgrade work?
- Common examples are older commercial and industrial buildings assessed below current earthquake standards, buildings changing Importance Level or use, properties where an insurer or buyer has requested strengthening, and structures where a reroof or major refurbishment has triggered a council or engineer review. Warehouses, offices, retail premises and light industrial buildings are typical. The right first step is an engineer's assessment of the existing structure; from there we document whatever upgrade scheme they specify.
- Do you handle seismic upgrades outside Palmerston North?
- Yes. Palmerston North and the Manawatū is our base, but seismic upgrade documentation is not tied to one council. We work on existing commercial and industrial buildings across New Zealand, coordinating with the structural engineer and the local building consent authority on each project. Palmerston North airport is five minutes away, which makes site visits around the country straightforward when we need to measure existing structure or review make-good on site.
Got an existing building that needs a seismic upgrade documented?
If you have an engineer's upgrade scheme, or you are at the stage of getting one, send us what you have. We will tell you plainly what the integration and documentation involves, including whether reroof, fitout or remediation work should be in the same programme. There is no cost to start the conversation.