Yes — installing a door viewer (also called a peephole) is one of the more approachable DIY security upgrades you can make to your home. No licensed trade is required, no building consent is needed, and with the right drill bit and a bit of patience, most NZ homeowners can complete the job in 30–60 minutes.
What Is a Door Viewer?
A door viewer is a small wide-angle lens fitted through a hole in your front door, letting you see who is outside without opening the door. Standard viewers have a field of view of around 180–200 degrees. They come in two threaded halves that screw together from each side of the door, clamping it in place. You can find a good range at Bunnings or Mitre 10, with prices generally ranging from around $10 to $50 as a rough guide, depending on quality and features.
Tools and Materials You'll Need
- Door viewer (choose the correct diameter — typically 14 mm or 25 mm)
- Power drill
- Spade bit or hole saw matching the viewer's barrel diameter
- Masking tape (to reduce tear-out on timber)
- Pencil and tape measure
- Flat-head screwdriver or coin (for tightening)
- Safety glasses
Choosing the Right Viewer
Before you buy, check two things:
- Door thickness — measure your door's thickness. Most viewers are adjustable for doors between 35 mm and 55 mm, but thicker solid-core or fire doors may need an extended-barrel viewer. Check the product packaging carefully.
- Barrel diameter — the hole you drill must match the viewer's barrel. Common sizes are 14 mm and 25 mm. Confirm this before drilling.
If you have a steel security door, a standard spade bit won't cut it — you'll need a metal-rated hole saw or step drill bit.
Step-by-Step Installation
1. Mark the Position
Stand at the door and mark the height at your eye level — typically between 1,500 mm and 1,600 mm from the floor for an average adult. Centre the mark horizontally on the door.
2. Protect the Door Surface
Apply masking tape over the mark on both sides of the door. This reduces splintering on timber doors and scratching on painted or PVC surfaces.
3. Drill the Hole
Using your spade bit or hole saw, drill from the outside face inward at a slight downward angle (a degree or two) so water can't pool in the barrel. Go slowly and keep the drill level. If you feel resistance change, ease off to avoid tear-out.
4. Fit the Viewer
Insert the outer lens barrel from the outside of the door. From the inside, thread on the inner eyepiece and tighten by hand, then snug it up with a flat-head screwdriver or coin — do not overtighten, as this can crack the lens housing.
5. Test It
Look through the viewer from the inside. You should have a clear, wide-angle view. If the image is blurry, the lens may be cross-threaded — unscrew and re-seat it.
Door Types and Special Considerations
| Door Type | Difficulty | Notes |
|---|---|---|
| Hollow-core timber | Easy | Drill carefully; support the far face |
| Solid-core timber | Easy–Moderate | Takes longer to drill through |
| Steel security door | Moderate | Use a metal hole saw; wear eye protection |
| uPVC / composite | Moderate | Check manufacturer's advice first |
| Fire-rated door | See note | May affect fire rating — check with your supplier |
Important: If your door is a fire-rated door (common between a garage and living area), drilling through it could compromise its fire rating. Check with the door manufacturer or a qualified locksmith before proceeding.
Does This Require a Building Consent?
Fitting a door viewer is a minor repair/maintenance task and is generally exempt from building consent under Schedule 1 of the Building Act 2004. However, rules can vary — always confirm with your local council if you're unsure. You can find general guidance at MBIE Building Performance.
Safety Tips
- Wear safety glasses when drilling, especially into steel doors.
- Keep fingers clear of the drill bit's exit point on the far side.
- If you're on a ladder or steps to reach the right height, make sure it's stable on a flat surface.
- Refer to WorkSafe NZ for general safe tool-use guidance.
When to Call a Professional
While this is a DIY-friendly job, there are situations where it's worth calling a qualified locksmith:
- Your door is a fire-rated or security-rated door and you're unsure about drilling it.
- You have a steel or armoured door and lack the right tools.
- You want a digital or smart door viewer (with a screen or camera), which may involve more complex installation.
- You'd like a locksmith to assess your overall door security at the same time — a worthwhile conversation.
A local locksmith can handle the job quickly and advise on the best viewer for your door type. You can find qualified locksmiths near you on tradedirectory.co.nz.
