A section plan is a vertical slice drawings showing the internal features of your property. It is similar to an elevation plan, however, it shows the internal features of the property. It is quite common to have the section plan drawn in the middle of the staircase of the property. The section plan is to help the architect to get an idea of the height of the internal floors of the property and features on the wall.
The section plan is usually combined with other plans on a measured building survey. This can include floor plans, elevations, etc…
To help you:
An example of a section is shown below:
It is important to note (to avoid confusion):
The difference between an elevation and a section is that the elevation shows the external vertical plan of the building and the section shows the internal. It is quite common that we get enquiries asking for external sections, which does not exists… So if you are looking for external plan you’d need an elevation plan.
Take a look at this article on elevations.