Refinishing cycles & scratches

A solid 19 mm T&G can be sanded 3–4 times over a life. An engineered board can be sanded as many times as its wear layer allows — often once, sometimes twice. Choose between recoat (screen and re-topcoat) and sand-back (back to bare timber) based on depth of damage.

Mechanism

ATFA's Specification for Solid Timber Flooring (installation, sanding, coating) covers prefinished solid T&G and site-finished flooring directly to joists or battens. Solid flooring direct to joists/battens must have a minimum thickness of 19 mm; this provides sacrificial thickness for multiple sand-backs. Bona Traffic HD TDS supports overcoating of previously lacquered surfaces: 'cleaning and superficial abrasion' followed by '1–2 x Bona Traffic HD' — i.e., a recoat rather than a sand-back where scratches are confined to the film.

Risk profile by species

SpeciesRiskNote & source
Solid Tg 19mm 3-4-full-sands Minimum 19 mm thickness direct to joists/battens; standard rule-of-thumb is sanding uses ~1–1.5 mm per full sand-back, leaving headroom for multiple refinishes over the board life.Source: atfa-specification-for-solid-timber-flooring-installation-sanding-and-coating.pdf p.1, 72
Engineered Thick Veneer 1-2-sands Engineered boards with a 3–6 mm wear layer can typically accept one or two full sand-backs; very thin wear layers (<2 mm) should be recoat-only.Source: atfa-specification-for-solid-timber-flooring-installation-sanding-and-coating.pdf (prefinished solid T&G section 6.0)
Prefinished Factory Finish recoat-only-typical ATFA spec section 6.0 covers prefinished solid strip flooring separately from site-finish; the factory finish is typically maintenance-recoated rather than fully sanded.Source: atfa-specification-for-solid-timber-flooring-installation-sanding-and-coating.pdf section 6.0

Mitigations

  • traffic-hd
    Recoat (screen + re-topcoat) when damage is scratches in the film only, not through to timber; Bona Traffic HD overcoat schedule: clean, superficial abrasion, 1–2 coats Traffic HD.
    Source: Bona_TrafficHD_TDS_AU.pdf p.2 'Previously lacquered surfaces'
  • Sand-back when damage is deep, or when colour-change is required. Use ATFA spec's coating schedule for the replacement system.
    Source: atfa-specification-for-solid-timber-flooring-installation-sanding-and-coating.pdf
  • craft-oil-2ktraffic-hd
    For oil-finished floors, Bona Craft Oil 2K floors can be maintenance-overcoated with additional Craft Oil 2K or overcoated with Traffic HD provided the procedure in the Craft Oil 2K TDS is followed.
    Source: Bona_Craft_Oil_2K_TDS.pdf p.5–6 (overcoating)

Bona product guidance

  • traffic-hd
    Overcoat-capable: clean + superficial abrasion + 1–2 coats Traffic HD. Recoat window depends on film condition; do not recoat over contaminated film.
    Source: Bona_TrafficHD_TDS_AU.pdf p.2
  • craft-oil-2k
    Maintenance coats of Craft Oil 2K can be applied directly; cross-over to Traffic HD is permitted per TDS provided the oil has cured and the surface is prepared per TDS.
    Source: Bona_Craft_Oil_2K_TDS.pdf p.5–6

Gaps in the corpus (no claim made)

  • No numeric 'mm per sand' rule in ATFA or Bona corpus; craft-industry norms are inferred rather than cited.
  • No Bona-published maximum number of overcoats for Traffic HD before a full sand-back is required.
Sources