Scale effect: small difference, large surface
A colour variation that looks acceptable on one board can read as a patchy surface across dozens laid side by side. On large surfaces, going one grade up usually pays for itself.
Where colour uniformity matters, steaming helps reduce the variation between boards.
What the tongue-and-groove profile does
Panelling is produced with an interlocking profile: the tongue of one board sits in the groove of the next. This speeds up installation and hides the movement caused by the timber working.
Thanks to the interlock, even if boards separate slightly the surface behind stays hidden — a real advantage over butt-jointed installation.
Jointed or solid
Panelling is produced both finger-jointed and solid. Jointed production reaches long lengths and lowers cost; solid is preferred where the joint pattern is unacceptable on the visible face.
For high ceilings, where a single long length is wanted, jointed production is often the only practical route.
Conditioning before installation
Panelling should sit in the space where it will be installed for a period beforehand. Fitted after the material has come close to the room's equilibrium, the risk of gapping and binding drops markedly.
During conditioning the packs should be opened so air can circulate, and boards should not sit directly on the floor.