The number of trucks required for delivery first and foremost depends on the size of the house. The bigger the house, the bigger the area of the elements and more volume in the trailers is required.
The second factor is the thickness of the elements. A more energy efficient house not only requires more material but also takes up more room in the trailer. The most common is the difference in the wall insulation layer between 195 mm and 245 mm which increases the thickness of the panel by about 15%. This difference can mean an extra truck for a typical single family house.
It also depends on the type of element delivered. Depending on the type of siding or simply the level of prefabrication required from the buyer, panel thickness can vary.
Buildings with complicated designs may require production of panles that are not optimal for delivery and therefore increase the number of trucks required.
As a rule of thumb a building kit for an outside finished house may require a truck for about every 30-40 m2 of floor. However this can vary a lot due to aforementioned reasons and in a price offer is always estimated looking at each project individually.