Sanding and finishing your timber floors is one of the most rewarding home improvement projects you can tackle — but choosing the right finish can feel overwhelming. The two most popular options in New Zealand are polyurethane and oil-based finishes, and they behave very differently. Understanding those differences will help you get a result you'll be happy with for years to come.
What Is Polyurethane Floor Finish?
Polyurethane (often called "poly" or "urethane") is a hard-wearing plastic resin that forms a protective film on top of the timber. Once cured, it creates a tough, sealed surface that sits above the wood grain rather than soaking into it. Polyurethane is available in water-based and oil-based formulations, and in a range of sheens from matte through to high gloss.
Water-based polyurethane dries faster, has lower VOC (volatile organic compound) emissions, and tends to stay clearer over time. Oil-based polyurethane takes longer to dry but is often considered more durable and gives timber a warmer, amber tone.
What Is an Oil Floor Finish?
Oil finishes — including hardwax oils and penetrating oils — work differently. Instead of forming a surface film, they soak deep into the timber fibres and cure from within. Popular products in NZ include brands like Rubio Monocoat and Loba, and you'll find a range of options at retailers such as Mitre 10 and Bunnings.
Oil finishes enhance the natural look and feel of the wood, leaving it feeling more tactile and "alive" underfoot. The result is typically a low-sheen, natural appearance that many homeowners prefer for character homes and rustic interiors.
Key Differences at a Glance
| Feature | Polyurethane | Oil Finish |
|---|---|---|
| How it works | Surface film | Penetrates timber |
| Appearance | Gloss to matte, can look "plastic" | Natural, low-sheen |
| Durability | Very hard, scratch-resistant | Softer, more prone to marks |
| Maintenance | Low — occasional clean | Higher — periodic re-oiling |
| Repair | Difficult (full sand often needed) | Easy spot repairs |
| Drying time | Hours to days | Often faster per coat |
| VOCs | Varies (water-based = lower) | Generally low |
| Cost (as a guide) | Moderate | Moderate to higher |
Durability and Traffic
For high-traffic areas — hallways, kitchens, open-plan living — polyurethane generally wins on durability. Its hard film resists scratches, scuffs, and moisture better than most oil finishes. This makes it a practical choice for families with kids or pets.
Oil finishes are softer and can show wear more readily, but here's the trade-off: when an oiled floor gets scratched or worn in one spot, you can spot-repair just that area without sanding the whole floor. With polyurethane, a damaged patch usually means sanding back the entire floor to get a seamless result — a significant job.
Appearance and Timber Feel
If you want to showcase the natural beauty of your NZ native timber — rimu, matai, kauri, or heart pine — an oil finish often produces a more authentic result. It doesn't add a visible layer on top, so the grain and texture remain front and centre. The floor feels like wood, not like wood under plastic.
Polyurethane, especially high-gloss versions, can give floors a "wet look" that some homeowners love and others find too artificial. Water-based polys in a satin or matte sheen are a good middle ground if you want protection with a more natural look.
Moisture and NZ Climate Considerations
New Zealand's climate varies enormously — from the humid north to the cold, damp south. BRANZ research highlights that moisture management is critical for timber floors, particularly in older homes with limited subfloor ventilation. Polyurethane's sealed surface offers better short-term moisture resistance, but if moisture gets underneath (common in older NZ homes), it can cause the film to lift or bubble. Oil finishes allow the timber to breathe slightly, which can be an advantage in certain situations.
In wet areas like bathrooms, neither finish is ideal for timber floors — refer to the NZ Building Code's E3 (Internal Moisture) requirements and consider purpose-built wet-area flooring instead. You can find guidance at MBIE Building Performance.
Maintenance Requirements
- Polyurethane: Sweep or vacuum regularly, damp-mop with a pH-neutral cleaner. Avoid harsh chemicals. Re-coat every several years depending on wear.
- Oil finish: Regular sweeping, clean with a compatible oil soap, and apply a maintenance oil coat every year or two (or as needed). High-traffic areas may need more frequent attention.
The ongoing maintenance commitment is worth factoring into your decision — especially if you're a landlord with obligations under the Healthy Homes Standards.
DIY or Professional Finish?
Applying either finish after sanding is within reach of a capable DIYer, but the preparation — particularly the sanding — is where most mistakes happen. Uneven sanding leaves visible marks that no finish will hide. A professional floor sander has the equipment and experience to get the surface right before a single drop of finish is applied.
When to Call a Professional
Hire a qualified floor sanding professional if:
- You're working with native NZ timbers (rimu, kauri, matai), which require careful sanding to avoid damage
- The floor has significant gaps, cupping, or structural issues
- You're unsure which finish suits your specific timber species and subfloor conditions
- You want a warranty-backed result
Floor finishing does not involve restricted electrical, plumbing, or gas work, so there are no licensing requirements for the finishing itself. However, if subfloor work uncovers drainage or electrical issues, those must be handled by a licensed professional registered with the EWRB or PGDB.
You can find experienced, local floor sanding professionals on tradedirectory.co.nz.