The most obvious cost driver is simply how much surface area needs to be covered, but the number of individual panels required to achieve that coverage also matters, since more panels generally mean more joins, more edge finishing and more installation time. Two walls of identical total size can end up priced quite differently if one requires significantly more individual panels to achieve the same coverage. Discussing panel configuration options with a supplier before finalising the design can sometimes reveal a more cost-effective layout without compromising the finished result. This is one of the easiest conversations to have early, since it costs nothing to ask and can meaningfully affect the final price.
Each individual panel is manufactured up to a maximum of 1180 by 2980 millimetres, so a wall close to that limit per panel generally needs fewer joins, and therefore less edge finishing and installation time, than one built from several smaller panels covering the same total area. This is one of the more straightforward factors to estimate accurately from an early survey, which is why it is usually one of the first numbers a supplier can confirm.