A wood floor sanding-and-varnishing job is more disruptive than most renovation work because the entire floor is the work surface — you cannot walk on it once coating begins, and dust and fumes need to be managed across the whole unit. This article walks through what actually happens on site, day by day, so homeowners can plan around it.

The schedule below is a typical 3-bedroom condominium with around 80-100 m² of parquet or wood flooring. Larger and more complex jobs scale up; tight studios scale down.

Before we start — site preparation

We confirm the scope at a free site visit and quotation. Once accepted, we issue a job sheet covering:

  • Areas to be sanded and recoated (and any areas excluded, such as wet-zone wood).
  • Board replacement scope (number of pieces, species match, location).
  • Coating system — standard water-based, oil-based or Bona — and number of coats.
  • Day-by-day schedule and homeowner responsibilities (move-out, valuables, pets, aircon settings).
  • Site access — lift booking with the condo management, working hours allowed by the MCST, dust control measures.

Homeowner prep (1-2 days before start):

  • Move all furniture and rugs out of the work area. We can quote optional moving service if needed.
  • Remove curtains low enough to touch the floor; tape or wrap any wall-fixed items within 30 cm of the floor.
  • Empty wardrobes that sit on the floor we are sanding (we can sand around standing wardrobes if the homeowner prefers, with a small visible band).
  • Disconnect and move out fragile electronics; cover anything that cannot be removed with plastic sheeting.

Day 1 — coarse sanding and board repairs

The crew arrives between 8:30 and 9:30 AM. Setup:

  • Plastic sheeting over doorways to seal the sanding area from the rest of the unit.
  • Dust extraction units (HEPA-equipped vacuums) attached to every sanding machine.
  • Skirting protection tape along the bottom of walls.

Drum sander pass 1 — coarse grit (P36-P40). This removes the old varnish and the top layer of wood, evening out wear marks, edge cups and any historic damage. The machine moves with the grain on plank floors; on patterned parquet (herringbone, basket-weave), passes are made diagonally.

Edge sander pass 1. The drum sander cannot reach the last 15 cm at walls and around fixed items. An edge sander handles the perimeter at matching grit.

Board replacement. Damaged or stained boards identified during the site visit are cut out and replaced with matching species. Replacement boards are usually slightly higher than the surrounding floor; they sand down flush in the next pass.

End of Day 1: bare wood, coarse-sanded. The unit is dusty even with extraction — we vacuum at end-of-day but a final clean happens before coating.

Day 2 — fine sanding and final preparation

Drum sander pass 2 — medium grit (P60-P80). Removes the coarse scratches from Day 1.

Drum sander pass 3 — fine grit (P100-P120). Final smoothing pass. Different coating systems specify slightly different end grits; we follow the manufacturer's recommendation for the product going down.

Edge sander pass 2 and 3. Matching grit progression at perimeters.

Corner work. Sharp internal corners and around radiator pipes, door jambs and other obstructions are sanded by hand or with a small orbital sander. This is the slowest part of the day.

Gap filling (optional). Where boards have gapped over time, a slurry of fine sanding dust plus a clear binder is troweled across the floor, filling the gaps. Filler is a cosmetic option — it cracks over years as the floor moves seasonally and is not always recommended. We discuss whether to fill before sanding starts.

Final vacuum and tack. The entire floor is vacuumed twice and tack-cloth wiped. The coating film will telegraph every speck of dust — preparation pays back during finishing.

End of Day 2: floor is bare, smooth and clean, ready for sealer.

Day 3 — sealer and first coat

Sealer / first coat. A primer-sealer (matched to the topcoat system) is rolled across the floor with a microfibre applicator. On most modern water-based systems, the sealer doubles as the first coat. Drying time: 1-3 hours for water-based, 6-12 hours for oil-based.

Intermediate sanding. Once the sealer is dry, a fine screen (P150-P220) on a buffer abrades it lightly to take down any raised grain. Vacuum and tack again.

Second coat (water-based). Same applicator, same direction. Most water-based finishes are tack-free in 1-2 hours and recoatable in 3-4 hours.

For oil-based systems, only one coat goes down on Day 3 and the second coat happens on Day 4 morning. The full schedule below assumes water-based.

End of Day 3: two coats on, varnish curing. No traffic permitted overnight.

Day 4 — final coat and finishing details

Third coat. Final topcoat goes down in the morning. For Bona Traffic HD or another 2K product, the two components are mixed on site immediately before application.

Touch-ups. Skirting paint scuffs from sanding, edge spots where the edge sander could not fully reach, and any minor blemishes are addressed.

Site clean. Plastic sheeting comes down, dust is removed from window sills and skirting, and the crew sweeps adjacent areas.

End of Day 4: floor is coated and curing. We close out the job with the homeowner — sign-off, care instructions, recommended cleaner.

Cure window — when furniture and rugs come back

The varnish is dry to touch within hours, but full cure (cross-linking complete) takes longer. During the cure window, the surface is vulnerable to soft pressure marks, indentations from heavy furniture legs and chemical staining.

  • Light foot traffic (socks, no shoes): 24 hours after final coat.
  • Normal walking, light furniture back: 3-4 days.
  • Heavy furniture (sofas, wardrobes, beds), rugs: 7 days for 1K systems, 7-10 days for 2K systems.
  • Full chemical resistance and pet claws: 14 days.

We mark the calendar with the homeowner at sign-off so the move-back is timed correctly.

What can go wrong, and how we prevent it

  • Dust nibs in the finish. Caused by inadequate vacuuming between coats or by the unit's aircon stirring up settled dust. We vacuum twice and tack between every coat, and we ask the homeowner to keep aircon off during coating.
  • Drum marks or sander lines. Caused by stopping a moving sander on the floor. Crew training avoids this — every sanding pass starts the machine moving before lowering and lifts before stopping.
  • Streaks or lap marks in the topcoat. Caused by recoating before the previous coat is dry, or by working in too small a section. We follow the manufacturer's pot-life and recoat windows, even when the floor "looks" ready earlier.
  • White edges or lifting boards within weeks. Caused by water intrusion (leak, wet mopping too soon, balcony splash). We brief the homeowner on the first-two-weeks routine — soft sweep only, no mopping for 14 days.
  • Varnish smell lingering. Normal for oil-based systems for 3-5 days. Water-based is significantly milder, usually clear within 24-48 hours.

What we don't claim

  • A fresh varnish coat does not make a damaged floor brand-new. Deep dents, dark water stains in the wood itself and historic structural movement are still visible, just sealed.
  • Gap filler is cosmetic and not durable. We recommend it only where the homeowner has discussed the tradeoff and accepted that the filler will crack over time.
  • Schedule is weather and condo-rule dependent. Heavy rain through an open window, an MCST work-hour rule change or a power outage can push the cure window by a day.

We commit to honest day-by-day communication. If something needs an extra day, we tell the homeowner the morning we know — not at the end of the project. Project-specific schedules, prices and warranties are confirmed in writing per job.