Laminate flooring is a popular choice in New Zealand homes — it looks great, it's durable, and it's a manageable DIY project. But one of the most common mistakes homeowners make is getting the expansion gap wrong. Too small and your floor can buckle; too large and it looks untidy under the skirting. Here's what you need to know.
What Is an Expansion Gap and Why Does It Matter?
Laminate flooring is a floating floor — it isn't glued or nailed to the subfloor. Instead, the planks lock together and sit freely, expanding and contracting as temperature and humidity change. New Zealand's climate varies considerably between regions and seasons, meaning your floor can move more than you might expect.
Without adequate space around the perimeter and at fixed objects, the floor has nowhere to go. The result is buckling, peaking, or gapping — all of which are expensive to fix and may void your product warranty.
How Much Gap Do You Actually Need?
As a general rule, most laminate flooring manufacturers recommend a minimum 10–12 mm expansion gap around the entire perimeter of the room — including at walls, door frames, cabinetry, pipes, and any other fixed object the floor runs up to.
However, always check your specific product's installation instructions first. Some manufacturers specify slightly different tolerances, and following their guidance is important for warranty purposes.
| Situation | Recommended Gap (general guide) |
|---|---|
| Perimeter walls | 10–12 mm minimum |
| Door frames & architraves | 10–12 mm minimum |
| Cabinetry & islands | 10–12 mm minimum |
| Pipes (e.g. heating) | 10–12 mm all around |
| Long runs over ~8–10 m | Consider a T-moulding break |
| Doorways between rooms | Use a T-moulding or threshold |
For longer rooms or open-plan layouts, a single continuous run of laminate can put significant pressure on the perimeter gaps. Many installers recommend adding a T-moulding expansion joint in doorways or at intervals in very large rooms to break up the run and reduce cumulative movement.
NZ Climate Considerations
New Zealand's humidity levels can swing noticeably between summer and winter, particularly in regions like Auckland (humid and warm) versus Central Otago (dry and cold). This seasonal movement is exactly what the expansion gap is designed to accommodate.
BRANZ research highlights that moisture management is critical in NZ homes. In areas prone to higher humidity — bathrooms, laundries, or homes near the coast — standard laminate flooring may not be the best choice at all. Look for moisture-resistant or waterproof laminate products if you're installing in these areas, and always check the manufacturer's suitability ratings.
Tools and Materials You'll Need
- Spacers (plastic expansion gap spacers, typically 10–12 mm) — available at Bunnings or Mitre 10
- Tape measure and pencil
- Pull bar and tapping block
- Jigsaw or mitre saw
- Underlay (if not pre-attached to planks)
- Skirting boards or scotia moulding to cover the gap
Step-by-Step: Maintaining the Gap During Installation
1. Prepare the subfloor
Ensure the subfloor is clean, dry, and flat. Humps or dips greater than around 3 mm over a 1.8 m span can cause problems with a floating floor.
2. Lay your underlay
Roll out underlay without overlapping joins. Tape seams as directed by the manufacturer.
3. Place spacers before you start
Insert plastic spacers against every wall before laying the first row. Keep them in place throughout the entire installation — don't remove them until the floor is complete and skirting is ready to go on.
4. Cut around fixed objects carefully
For pipes, use a hole saw to cut the plank, then cut a small section out to slot it in place. Leave the full gap around the pipe and cover with a pipe collar.
5. Cover the gap with skirting or scotia
The expansion gap should be hidden, not filled. Never fill it with silicone, caulk, or adhesive — this defeats the purpose entirely. Refit skirting boards or nail scotia moulding over the gap. The covering should sit over the gap without pressing down on the floor.
Common Mistakes to Avoid
- Removing spacers too early — the gap can close before skirting goes on
- Filling the gap with silicone or caulk — this locks the floor and causes buckling
- Forgetting gaps at internal door frames — undercut the architrave and slide the laminate underneath, maintaining the gap
- Ignoring long runs — cumulative movement in large rooms needs a T-moulding break
- Skipping acclimatisation — let your laminate sit in the room for at least 48 hours before installation so it adjusts to the local temperature and humidity
When to Call a Professional
Laminate flooring installation is generally considered a DIY-friendly job, but there are situations where it pays to bring in a qualified flooring installer:
- Large or complex layouts with multiple rooms, stairs, or intricate cuts
- Subfloor issues such as significant unevenness, moisture problems, or damaged particleboard that may need repair or replacement
- Underfloor heating systems — laminate over hydronic or electric underfloor heating has specific requirements around maximum surface temperatures and gap sizing that vary by product
- Warranty requirements — some premium laminate products require professional installation to maintain the manufacturer's warranty
A qualified flooring installer will get the expansion gaps right first time and ensure your floor performs well for years. You can find experienced local flooring professionals on tradedirectory.co.nz.