Once laid and finished, a solid board and an engineered board can look identical. The difference is in the construction, and it decides how the floor is installed, where it can go and how it is looked after.
Solid timber
A solid board is milled from a single piece of hardwood, timber all the way through. Heritage, Topdeck's solid range, is milled in 14mm and 18mm profiles from Australian and imported hardwoods. It is supplied raw, to be sanded and finished on site, or pre-finished in 12 layers of PPG water-based polyurethane.
Solid timber is fixed to the subfloor. The Heritage installation guide sets the fixing by board width: boards of 80–90mm are secret-nailed and glued, and boards of 92–130mm are full-trowel glued and secret-nailed. Heritage is never floated. It is supplied at an average of 10–12% moisture content, and the guide asks for acclimatisation by measurement, checking the boards against the conditions they will live in, rather than by a set number of days.
Engineered timber
An engineered board has a hardwood veneer, the timber you see and walk on, bonded to a multi-ply core. Rhine is a 14mm engineered board, and so is most of Provenance: a 3mm Australian or Pacific hardwood veneer, 2mm on selected boards, on an 11mm multi-ply core. Provenance's Burmese Teak is 15mm, with a 3mm teak veneer and tongue-and-groove joints. Rhine has a 2mm or 3mm European oak veneer on a multi-ply core.
The core gives engineered timber more ways to be installed. Provenance plank can be laid as a floating floor on an approved acoustic underlay, or by full-spread direct stick. Rhine plank can be glued down, or floated with glued tongue-and-groove joints where the room and subfloor suit. Herringbone and chevron, in both ranges, are adhesive-fixed.
Finishes
Heritage pre-finished boards carry 12 layers of PPG water-based polyurethane. Provenance's Australian and Pacific boards have nine layers of Treffert UV-cured lacquer, in matte, ultra matte and semi-gloss. Rhine has nine layers of Sherwin-Williams ultra-matte UV lacquer, brushed and matt.
Underfloor heating
The Topdeck Limited Warranty lists underfloor heating as not suitable for Heritage or Provenance. For Rhine, it excludes floor heating other than hydronic heated slabs. A heated floor is raised with Topdeck before anything is specified.
Care and refinishing
Day to day, the two are cared for in the same way: swept or vacuumed with a soft head, cleaned with a pH-neutral cleaner and a microfibre mop, never wet-mopped or steam-mopped, and kept at 45–60% relative humidity and 18–26°C. Both can be refinished by a professional sanding and polishing contractor.
Which suits the project
Solid suits a floor fixed to the subfloor, and projects that want a raw board sanded and coated on site. Engineered suits projects that need a floating installation, a wider board, or a herringbone or chevron pattern. In both, the species is the starting point: see Heritage, Provenance and Rhine.
