When ensuring universal accessibility of buildings, we usually focus first on overcoming larger height differences, such as stairs. However, we often forget the importance of thresholds and edges that are too high and lack contrast. These obstacles can significantly affect the accessibility of buildings. Even a 15-millimeter height difference can determine whether a person using a wheelchair will be able to enter a building or space, and whether a person with visual impairment will be able to safely overcome the obstacle.
Edges and thresholds often appear as obstacles at the entrances to buildings, as well as at the junctions of different floor surfaces, at shower entrances, between interior door frames, and at transitions from the interior to the exterior (e.g., balconies, terraces). It is best if there is no threshold or edge, or if it is level with the floor. Where this is not possible, the following elements must be taken into account in the appropriate design and construction, as required by applicable legislation:
- the raised threshold/edge must not be higher than 15 mm,
- the raised threshold/edge must contrast with the surrounding floor surface,
- if the threshold/edge is raised by more than 5 mm, it must be rounded down on both sides,
- an existing raised threshold/edge may be adapted with an appropriate short ramp.