Technically, yes — you can use a random orbital sander on a floor, but for an entire room it's rarely the right tool for the job. A random orbital sander is designed for finishing work and small surfaces, not for stripping back a full hardwood or pine floor efficiently. Using one across a whole room will take many times longer, deliver uneven results, and wear through sanding discs at a frustrating rate. Here's what you need to know before you start.
What a Random Orbital Sander Is Good For
A random orbital sander (sometimes called a ROS) uses a circular pad that moves in a random elliptical pattern to reduce swirl marks. It's excellent for:
- Light scuff-sanding between coats of finish
- Spot repairs on small damaged areas
- Edges and tight corners when paired with a detail sander
- Finishing passes after a drum sander has done the heavy lifting
For these tasks, a random orbital sander is genuinely useful and gives a fine, smooth surface ready for staining or coating.
Why It Struggles on a Full Floor
The core problem is material removal rate. A drum or belt floor sander uses a large abrasive drum spinning at high speed to aggressively cut back old finish, paint, stains, and surface timber. A random orbital sander simply doesn't have the power or abrasive surface area to do this efficiently across, say, a 20 m² lounge floor.
Expect these issues if you try it:
- Extremely slow progress — what a drum sander does in an hour could take a full weekend
- Uneven sanding — you may create dips and waves, especially on softer NZ pine floors
- Disc clogging — old polyurethane and paint load up discs very quickly
- Motor burnout — running a handheld ROS for hours is hard on the tool and your wrists
- Poor results on cupped or uneven boards — a drum sander's weight and power levels boards; an orbital sander follows the surface
The Right Tools for Sanding a Full Floor
| Tool | Best Use | Typical Hire Cost (Guide Only) |
|---|---|---|
| Drum floor sander | Main field sanding, heavy material removal | ~$80–$130/day |
| Edge sander (disc sander) | Perimeter within ~150 mm of walls | ~$60–$100/day |
| Random orbital sander | Between-coat scuffing, spot work | Own or ~$30–$50/day |
| Detail/corner sander | Tight corners, door stops | Own or ~$20–$40/day |
Hire costs are a rough guide only and vary by region and supplier. Always confirm with your local hire shop.
Most NZ hire shops — including those at Bunnings and Mitre 10 — stock drum and edge sanders for daily hire. PlaceMakers trade stores may also point you toward specialist hire companies.
Step-by-Step: Sanding a Floor the Right Way
1. Prepare the room
Remove all furniture, curtains, and rugs. Check every board for raised nails or staples and punch them at least 3 mm below the surface — a nail will shred a sanding belt instantly.
2. Start with the drum sander
Begin with a coarser grit (typically 40–60 grit) to remove old finish and level the boards. Work diagonally across the grain first if the floor is badly cupped, then with the grain. Keep the machine moving at all times — stopping while the drum is running will gouge the floor.
3. Edge sand the perimeter
The drum sander can't reach the edges. Use a disc edge sander around the perimeter, feathering into the drum-sanded field.
4. Progress through grits
Work up through 60, 80, and 100–120 grit, vacuuming thoroughly between each pass. Finish with your random orbital sander using 120 grit for a final smooth pass — this is where it earns its place.
5. Clean and coat
Vacuum, tack-cloth, and apply your chosen finish. Popular NZ options include water-based polyurethane from Resene or Dulux, or oil-based products from Wattyl. Always follow the manufacturer's recoat times and ventilation requirements.
Dust and Safety
Floor sanding generates enormous amounts of fine dust. This is a genuine health hazard — fine timber dust is classified as a respiratory irritant, and old floors may have lead-based paint, other hazardous coatings, or potentially asbestos-containing materials. WorkSafe NZ recommends appropriate respiratory protection (P2 respirator minimum), eye protection, and good ventilation. Seal off doorways with plastic sheeting to contain dust. Most hire drum sanders have a dust bag, but they don't capture everything — expect cleanup.
When to Call a Professional
Floor sanding looks straightforward but is genuinely skill-dependent. A drum sander used incorrectly for even a few seconds can gouge deeply into timber that can't be recovered. Consider hiring a professional floor sander if:
- Your floor is parquet, engineered timber, or very thin boards (less than ~12 mm solid timber above the tongue)
- The floor has significant cupping, crowning, or damage
- You're unsure about the coating type (some coatings require specific preparation)
- You simply want a guaranteed, high-quality result
A qualified floor sanding professional has the right machinery, experience, and finishing products to transform a tired floor efficiently. You can find trusted local floor sanding tradespeople on tradedirectory.co.nz.
For guidance on timber floor standards and acceptable finishes, BRANZ is an excellent NZ-specific technical resource.
