Yes — installing architrave around a door frame is one of the more approachable DIY joinery tasks for a NZ homeowner. It doesn't require a building consent, involves no restricted trade work, and with the right tools and a bit of patience you can achieve a clean, professional-looking result. That said, accurate mitred cuts and tight joints do take practice, so don't be discouraged if your first attempt needs a little filler.
What Is Architrave and Why Does It Matter?
Architrave (sometimes called door trim or casing) is the decorative moulding that frames the visible gap between a door lining and the surrounding wall. It hides the junction between the lining and the plasterboard or wall cladding, gives the doorway a finished look, and protects the edges from knocks. In NZ homes you'll commonly see flat, bevelled, or ogee-profile architrave in either pine or MDF.
Tools and Materials You'll Need
- Tape measure and pencil
- Mitre saw (or a good-quality mitre box and hand saw)
- Nail gun or hammer and lost-head nails (40–50 mm for the frame, 25–30 mm for the lining edge)
- Wood glue
- Coping saw or block plane (for fine adjustments)
- Sandpaper (120–180 grit)
- Flexible gap filler or paintable acrylic sealant (e.g. Sika or similar)
- Primer and paint — Resene and Dulux both offer excellent trim paints suited to NZ conditions
Step-by-Step: Fitting Architrave
1. Mark Your Reveal Line
The reveal is the small setback (typically 6–8 mm) between the inner edge of the door lining and where the architrave sits. Use a combination square to mark a consistent reveal line all the way around the lining on both sides of the door. This line is your guide for positioning every piece.
2. Cut and Fit the Head (Top) Piece First
Cut both ends of the head piece at 45° mitre angles, leaving a little extra length. Hold it against the reveal line and mark the exact length. Re-cut to final length. The mitre should point outward at each top corner.
3. Cut the Side Legs
Cut the top of each side leg at 45° to match the head piece mitre. Hold each leg in place, mark the bottom length (usually cut square to sit on the floor or skirting), and cut to length. In NZ homes with skirting board, the architrave typically scribes over or butts against the skirting — a small plinth block can make this junction much easier if your profiles don't match neatly.
4. Dry-Fit Before Nailing
Always dry-fit all three pieces together before committing. Check that mitre joints close tightly with no gaps. If a joint is slightly open, a block plane or fine sandpaper on the mitre face can close it up.
5. Glue and Nail
Apply a small amount of wood glue to each mitre joint. Nail the architrave to the door lining with shorter nails (into the lining) and to the wall framing stud with longer nails. Nail through the mitre joints at the corners to pull them tight. Punch all nail heads just below the surface with a nail punch.
6. Fill, Sand and Paint
Fill nail holes with a suitable wood filler or stoppings compound. Once dry, sand smooth. Run a fine bead of paintable acrylic sealant along the wall edge of the architrave to seal the gap against the plasterboard — this prevents cracking as the house moves (important in NZ given our seismic activity and timber framing movement). Prime bare timber or MDF before applying your topcoat.
Choosing the Right Architrave Profile and Material
| Material | Pros | Cons |
|---|---|---|
| Finger-jointed pine | Cost-effective, takes paint well | Can show joints if not primed properly |
| Clear pine | Attractive grain, can be stained | More expensive |
| MDF | Very smooth, stable, paint-ready | Susceptible to moisture — avoid wet areas |
| Primed MDF | Ready to paint, consistent | Heavier, edges can swell if wet |
You'll find a good range of profiles and sizes at Bunnings, Mitre 10, and PlaceMakers.
NZ Building Code and Consent Considerations
Fitting architrave is cosmetic finishing work and does not require a building consent under the NZ Building Code. It is not restricted trade work — no licence is needed. However, if you are replacing a door frame itself (the structural lining or the door jamb), or if the work involves alterations to the wall framing, you should check with your local council whether consent is required. The MBIE Building Performance website is a good starting point for understanding what work is exempt.
Tips for a Better Finish
- Seal MDF edges with a shellac-based primer before painting — MDF soaks up water-based paint and swells if left unsealed.
- In humid areas (bathrooms, laundries), consider moisture-resistant MDF or primed pine, and ensure good ventilation in line with Healthy Homes standards if the property is a rental.
- If your walls are out of plumb or the lining is twisted, you may need to back-cut (undercut) the architrave slightly so it sits flat.
- A nail gun makes the job significantly faster and reduces the risk of splitting the timber.
When to Call a Professional
While architrave installation is DIY-friendly, consider hiring a qualified joiner if:
- You have complex profiles, curved doorways, or heritage mouldings to match
- The door frame or lining itself is damaged and needs replacing (this may involve structural work)
- You want a guaranteed finish on a high-visibility area like an entrance or feature hallway
- You simply don't have the tools or confidence for accurate mitre cuts
A skilled joiner can typically fit a set of door architraves quickly and to a very high standard. You can find qualified local joiners and tradespeople on tradedirectory.co.nz.
