Replacing a broken glass panel in a French door is a job some confident DIYers can tackle — but there are important rules around safety glazing in New Zealand that you must understand before you start. Get it wrong and you could face a compliance issue, or worse, a serious injury.
Understanding NZ Safety Glazing Requirements
This is the most critical part of any French door glass replacement. Under the New Zealand Building Code clause F4 (Safety from Falling) and the associated standard NZS 4223, glass in certain locations must be safety glass — either toughened (tempered) or laminated.
French doors almost always fall into a critical location because the glass panels are:
- At or near floor level (within 500 mm of the floor in many cases)
- In a door that people walk through regularly
- Subject to impact risk
This means you must replace the broken panel with compliant safety glass — standard float glass is not acceptable. Using the wrong glass type is a Building Code breach and a genuine safety hazard. Check MBIE Building Performance for guidance on glazing requirements, or ask your local council if you're unsure.
Do You Need a Building Consent?
Like-for-like replacement of a broken glass panel is generally considered maintenance and is listed under Schedule 1 of the Building Act as exempt from building consent — provided you replace it with glass of the same or better specification. However, always confirm this with your local council before starting, as interpretations can vary. MBIE Building Performance has useful guidance on consent exemptions.
What Tools and Materials You'll Need
If you've confirmed the job is within your skill level and the panel is a manageable size, here's what you'll typically need:
- Safety glasses and heavy leather gloves (non-negotiable when handling broken or new glass)
- Glazing putty or glazing tape/foam tape (depending on your door's bead system)
- Glazing beads or a putty knife
- Screwdriver or small pry bar (for removing beads)
- Tape measure and glass cutter (if cutting your own glass — not recommended for safety glass)
- Replacement toughened or laminated safety glass, cut to size
- Silicone sealant compatible with your door frame material
Important: Safety glass (toughened or laminated) cannot be cut on-site after it's been processed — it must be ordered pre-cut to the exact size from a glazing supplier. Measure carefully: width and height of the rebate opening, and the rebate depth.
Step-by-Step: Replacing the Glass Panel
1. Make the Area Safe
Wear gloves and safety glasses. Carefully remove all broken glass fragments and place them in a cardboard box or thick plastic bag — never loose in a rubbish bin. Vacuum up any small shards.
2. Remove the Glazing Beads
Most modern French doors use push-in or screwed glazing beads (timber or uPVC strips) that hold the glass in the rebate. Gently pry these off with a putty knife or flat screwdriver, working carefully to avoid splitting timber beads you want to reuse.
3. Remove Old Putty or Tape
Clean out any old glazing putty, foam tape, or silicone from the rebate. A chisel or putty knife works well for this. The rebate must be clean and dry before the new glass goes in.
4. Measure and Order Your Glass
Measure the rebate opening carefully — measure twice. Subtract around 3–5 mm from each dimension to allow for expansion and fitting clearance (your glazing supplier can advise the exact tolerance). Order toughened safety glass to the correct thickness (commonly 4 mm or 6 mm for French doors — check what was there originally).
5. Fit the New Glass
Place setting blocks (small rubber packers) at the bottom of the rebate to support the glass and keep it centred. Carefully lower the glass into the rebate. Apply glazing tape or silicone to the rebate as required by your door type, then refit the glazing beads firmly.
6. Seal and Finish
Apply a neat bead of compatible silicone sealant where required, smooth it off, and allow to cure fully before exposing the door to weather.
When to Call a Professional
There are several situations where you should call a qualified glazier rather than attempting this yourself:
- The panel is large or heavy (anything over roughly 0.5 m² can be very difficult and dangerous to handle alone)
- The door is double-glazed — IGUs (insulated glass units) must be factory-made and fitted correctly to maintain thermal and weathertight performance
- You're not confident about the safety glass requirements or measuring accurately
- The door frame itself is damaged and needs repair
- You want peace of mind that the work is compliant with NZS 4223
A licensed glazier will source the correct safety glass, ensure compliance, and often complete the job faster than a DIY attempt. You can find qualified local glaziers on tradedirectory.co.nz.
A Note on Safety
Broken glass causes serious lacerations. Always wear cut-resistant gloves and eye protection, never rush, and dispose of broken glass responsibly. If a large pane has shattered in place, consider calling a professional to handle the removal — it's simply not worth the risk.
For rental properties, landlords should also be aware of their obligations under the Healthy Homes standards, which include requirements around draught stopping and weathertightness — a broken or poorly fitted glass panel could be relevant.
Window & Glass Association
