In New Zealand, glaziers and joiners often work closely together — and in many cases, one tradesperson or company can handle both aspects of a window or door job. Whether you need one trade or two depends on the scope of your project, the type of joinery involved, and whether building consent is required.
What Does a Glazier Actually Do?
A glazier specialises in cutting, fitting, and installing glass into frames. This includes:
- Replacing broken or cracked panes in existing frames
- Installing double glazing or insulated glass units (IGUs)
- Fitting glass into shower screens, splashbacks, and balustrades
- Glazing new or replacement window and door frames
- Working with safety glass, laminated glass, and toughened glass to meet the NZ Building Code (in particular, Clause F4 – Safety from Falling and Clause G7 – Natural Light (which sets minimum natural light requirements for habitable spaces))
For straightforward glass replacements — like swapping a broken pane in an existing aluminium frame — a glazier alone is usually all you need.
What Does a Joiner Do?
A joiner (or window and door joiner) manufactures and installs the frames themselves — the aluminium, timber, or uPVC surrounds that hold the glass. Joinery work includes:
- Supplying and fitting new window or door frames
- Replacing rotted or damaged timber joinery
- Installing new aluminium joinery in a renovation or new build
- Ensuring frames meet weathertightness requirements under NZ Building Code Clause E2 (External Moisture)
Some joiners are also trained glaziers, and many joinery companies employ glaziers in-house or subcontract them as part of a complete window installation service.
When One Tradesperson Can Do Both
Many glazing companies in New Zealand offer a full window replacement service — supplying the joinery frame, glazing it with the appropriate glass, and installing the complete unit. This is common for:
- Aluminium joinery replacements (e.g., upgrading single-glazed aluminium windows to double glazing)
- Retrofit double glazing using secondary glazing systems
- Shower screen and frameless glass installations where the glazier fabricates and installs the entire assembly
If you're getting quotes for a full window replacement, ask the glazier upfront whether they supply and install the joinery frame as well as the glass. Many will — but not all.
When You Likely Need Separate Trades
There are situations where you'll want a dedicated joiner and a separate glazier, or where a specialist is clearly required:
- Timber joinery repairs or replacements — a joiner with carpentry skills is best placed to work with timber frames, especially on older villas or bungalows where custom sizing is needed
- New builds or major alterations — these typically require a Licensed Building Practitioner (LBP) to carry out or supervise restricted building work; check www.lbp.govt.nz to verify credentials
- Heritage or character homes — specialist joiners familiar with traditional NZ construction methods are worth seeking out
- Large commercial glazing projects — these often involve structural glazing engineers, façade contractors, and glaziers working as separate specialists
Building Consent: Do You Need One?
This is an important question. Replacing like-for-like glass in an existing frame generally falls under Schedule 1 of the Building Act as exempt work — meaning no consent is required. However, if you're:
- Changing the size or location of a window or door opening
- Altering the structure of the wall
- Installing new joinery as part of a larger renovation
…then a building consent may be required. Always check with your local council before starting work. MBIE Building Performance has useful guidance on what triggers consent requirements.
Weathertightness and the NZ Building Code
One of the most critical aspects of any window or door installation in New Zealand is weathertightness. Poorly installed joinery is a leading cause of leaky building issues. Ensure whoever does the work:
- Follows the requirements of NZ Building Code Clause E2
- Uses appropriate flashings, sealants, and installation methods
- Can provide documentation if the work requires consent
BRANZ publishes technical guidance on window and door installation that both glaziers and joiners should be familiar with.
Healthy Homes and Insulation Considerations
If you're a landlord upgrading windows, note that double glazing can contribute to Healthy Homes Standards compliance around heating and draught stopping. Tenancy Services has the full requirements. A good glazier or joinery company can advise on the most cost-effective upgrades for your rental property.
When to Call a Professional
Glazing and joinery installation should always be carried out by experienced tradespeople. While replacing a small pane of glass might seem straightforward, safety glass requirements under the NZ Building Code are strict — using the wrong glass type in the wrong location (near doors, low-level panels, or wet areas) can be a serious safety hazard. For any job involving:
- Structural changes to walls or openings
- New joinery installation in a consented project
- Safety-critical glazing (balustrades, shower screens, low-level glass)
- Heritage or complex timber joinery
…always engage a qualified professional. You can find experienced local glaziers and joiners on tradedirectory.co.nz.
Window & Glass Association
