Hiring a professional floor sander is one of the best investments you can make in your home's timber floors. A skilled tradesperson follows a structured, multi-stage process to strip back years of wear, level the surface, and apply a durable finish — all while protecting your home and meeting New Zealand standards for safe work practices.
Initial Inspection and Assessment
Before any machine touches your floor, a professional will carry out a thorough inspection. They'll assess:
- Timber species and condition — different species (rimu, kauri, pine, oak) have different hardness and grain characteristics that affect sanding technique
- Floor thickness — older NZ homes often have native timber boards that have been sanded before; a tradesperson will check there's enough timber remaining to sand safely
- Existing finish — whether it's polyurethane, oil, wax, or paint affects the approach and grit sequence
- Damage and defects — loose boards, protruding nails, gaps, cupping, or staining are all noted
- Subfloor movement — squeaks or flex can indicate issues that need addressing before sanding begins
This assessment shapes the entire job plan. A good tradesperson will talk you through what they find and set realistic expectations.
Preparation Work
Proper prep is critical. The professional will:
- Clear the room — all furniture, rugs, and fittings are removed
- Punch nails below the surface — any nail heads sitting proud of the timber are punched down to avoid tearing sanding belts and leaving scratches
- Check for hazards — in homes built before the mid-1980s, some floor finishes or adhesives may contain asbestos. If there's any doubt, testing is recommended before sanding. WorkSafe NZ has guidance on managing asbestos safely
- Seal off doorways — dust containment sheeting is hung to limit fine dust spreading through the house
- Protect skirting boards and cabinetry where needed
The Sanding Stages
This is the heart of the job, and it's done in multiple passes using progressively finer abrasives — a process called grit sequencing.
Coarse Sanding (Cutting)
The first pass uses a drum sander or belt sander with a coarse grit (typically 24–40 grit) to strip the old finish and level the surface. The machine is run at an angle to the boards (usually 15–45 degrees) on heavily cupped or uneven floors, then with the grain for subsequent passes.
Medium Sanding
A medium grit (around 60 grit) removes the scratches left by the coarse pass and continues to refine the surface.
Fine Sanding
A fine grit (80–100 grit) smooths the surface ready for finishing. Some jobs require an extra pass at 120 grit depending on the finish being applied.
Edge Sanding
A edge sander (a smaller disc sander) is used along walls and in corners where the drum sander can't reach. This requires skill — edge sanders can leave swirl marks if not handled carefully.
Detail Sanding
Corners, tight spots, and areas around door frames are finished by hand or with a detail sander to ensure an even result across the whole floor.
Filling and Repairs
After the main sanding passes, the tradesperson will mix timber filler — often using fine sawdust from your own floor combined with a flexible filler — to fill gaps, cracks, and nail holes. This keeps the colour match as close as possible. Larger gaps may be filled with timber slivers or a flexible gap filler suited to moving floors.
Vacuuming and Tack Cleaning
Before any coating goes down, the floor is thoroughly vacuumed and then wiped with a tack cloth or damp cloth to remove every trace of dust. Any dust left on the surface will be trapped in the finish and ruin the result.
Applying the Finish
The choice of finish is usually discussed with you beforehand. Common options in New Zealand include:
| Finish Type | Appearance | Durability | Notes |
|---|---|---|---|
| Water-based polyurethane | Clear, low odour | High | Fast drying, popular choice |
| Oil-based polyurethane | Warm amber tone | Very high | Longer dry time, strong odour |
| Hardwax oil | Natural, matte | Moderate | Easier to spot-repair |
| Penetrating oil | Very natural | Moderate | Requires regular maintenance |
Finish is applied in two to three coats, with a light screen sand (using a fine screen pad on a buffer) between coats to ensure good adhesion and a smooth result. Each coat must be allowed to cure fully before the next is applied — your tradesperson will advise on drying times, which vary with temperature and humidity. New Zealand's variable climate means drying times can differ significantly between summer and winter.
Brands like Resene, Dulux, and Wattyl all supply professional-grade floor coatings used by NZ tradespeople.
Final Inspection and Handover
Once the final coat has cured, the professional will inspect the floor in good light, touch up any missed spots, and remove all dust sheeting and equipment. They'll advise you on:
- How long to stay off the floor before walking on it
- When to replace furniture (usually 24–72 hours minimum)
- How to clean and maintain the finish
- When a maintenance coat might be needed in future
When to Call a Professional
Floor sanding is a skilled trade. Drum sanders are powerful machines that can quickly gouge or unevenly sand a floor if used incorrectly — damage that can be very difficult to fix. You should always call a qualified floor sanding professional if:
- Your floor is made of native NZ timbers (rimu, kauri, matai) which require careful technique
- The floor has been sanded before and timber thickness is a concern
- You suspect old finishes or adhesives may contain asbestos
- The floor has significant damage, cupping, or movement
- You want a guaranteed, quality result
You can find qualified, experienced floor sanding professionals in your area right here on tradedirectory.co.nz.
