Replacing a torn or sagging fly screen mesh is one of the most satisfying DIY jobs around the home — it's inexpensive, requires no special licences, and makes a real difference to keeping insects out during those warm NZ summers. Most standard aluminium or timber-framed fly screens can be re-meshed in under an hour with a few basic tools.
What You'll Need
Before you start, gather the following:
- Replacement fly screen mesh — fibreglass mesh is the most common and easiest to work with; aluminium mesh is more durable but harder to handle
- Spline — the rubber or vinyl cord that holds the mesh in the channel (check the width of your existing spline, typically 3 mm–5 mm)
- Spline roller tool (also called a screen rolling tool) — a small double-ended wheel tool
- Utility knife or sharp scissors
- Flathead screwdriver
- Tape measure and marker
- A flat work surface (a table or workbench is ideal)
You can find mesh, spline, and spline rollers at Bunnings or Mitre 10. Fibreglass mesh is generally recommended for most NZ homes — it's flexible, rust-resistant, and suits our coastal and humid environments well.
Step 1: Remove the Screen Frame from the Window
Most fly screen frames simply lift out or unclip from the window. Look for small tabs or clips at the corners. Set the frame on your flat work surface. If the frame is damaged or bent, this is a good time to assess whether it needs replacing entirely — replacement frames are available at hardware stores in standard sizes, or can be cut to fit.
Step 2: Remove the Old Spline and Mesh
Using a flathead screwdriver, prise up one corner of the spline (the rubber cord sitting in the groove around the frame edge). Once you have a section lifted, pull the spline out by hand — it should come away in one or two pieces. The old mesh will then lift straight off. Discard both the old mesh and old spline; reusing old spline is not recommended as it becomes brittle and won't grip properly.
Clean out the spline channel with a dry cloth to remove any dust or debris.
Step 3: Cut the New Mesh to Size
Unroll your new mesh over the frame, leaving at least 50 mm of overhang on all four sides. This extra material gives you something to hold tension against while you work the spline in. Cut the mesh roughly to size with scissors — you'll trim the excess neatly at the end.
Step 4: Roll in the New Spline
This is the key step. Work on one side at a time:
- Lay the mesh flat over the frame so it covers the spline channel.
- Place the new spline on top of the mesh, aligned with the channel.
- Using the concave wheel of the spline roller, press and roll the spline firmly into the channel, pushing the mesh down with it. Apply steady, even pressure.
- Start with one of the longer sides, then do the opposite long side (pulling the mesh gently taut as you go), then the two short sides.
Tip: Don't pull the mesh too tight — you want it snug and flat, not stretched so hard it distorts the frame. Fibreglass mesh is forgiving; aluminium mesh can crease if over-tensioned.
At corners, use the convex wheel of the spline roller to press the spline neatly into the corner without bunching the mesh.
Step 5: Trim the Excess Mesh
Once all four sides of spline are seated, use a sharp utility knife to trim the overhanging mesh. Run the blade along the outside edge of the spline channel, keeping the knife angled slightly outward so you don't accidentally cut into the spline itself. Take your time here — a clean trim gives a professional finish.
Step 6: Refit the Screen Frame
Clip or slide the frame back into the window opening. Check that the mesh is sitting flat with no sags or bulges. Give it a gentle press in the centre — it should feel firm and springy.
Choosing the Right Mesh
| Mesh Type | Best For | Notes |
|---|---|---|
| Fibreglass | Most homes, general use | Easy to work with, won't rust |
| Aluminium | High-traffic or pet households | More durable, harder to roll |
| Pet-resistant mesh | Homes with cats or dogs | Heavier weave, very tough |
| Solar/privacy mesh | Sun-facing windows | Reduces glare and heat gain |
For most NZ homes, standard fibreglass mesh in a charcoal or grey colour gives the best outward visibility.
Tips for a Long-Lasting Result
- Match your spline diameter to the channel width — too thin and the mesh will pop out; too thick and it won't seat properly.
- In coastal areas, fibreglass mesh is preferred over aluminium as it won't corrode in salt air.
- If your frame is aluminium and has badly corroded corners, consider having a new frame made up — many hardware stores offer a frame-cutting service.
- NZ's Healthy Homes standards require rental properties to be free from gaps that allow draughts or pest entry, so landlords should keep fly screens in good repair.
When to Call a Professional
Replacing fly screen mesh is not restricted work — any homeowner can do it safely. However, consider calling a local handyman if:
- The window frame itself is damaged, rotten, or requires repair
- You have large or unusually shaped screens that are difficult to handle alone
- You're dealing with louvre or specialty window systems
- You'd simply prefer a guaranteed, tidy result
A qualified handyman can re-mesh multiple screens quickly and often source materials at trade pricing. You can find experienced local handymen on tradedirectory.co.nz.
Safety note: When working at height to remove or refit screens on upper-storey windows, always use a stable ladder and have a second person to assist. Follow safe ladder practices as outlined by WorkSafe NZ.
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