What is a stair riser?
A stair riser is the more or less vertical board between two treads of a staircase. A stair with risers is a closed-riser stair; one without them is an open-riser staircase. In Dutch the board is called a stootbord.
The riser does several jobs. It closes the stair so dust and debris do not fall through. It makes the space under the stair usable as an enclosed area, such as an understairs cupboard. It also adds stiffness to the staircase.
Keep the board and the measurement apart. The riser is a component. The rise, often called the riser height, is a dimension: the vertical distance from the top of one tread to the top of the next. Because of tread thickness and the way the board is housed, the height of the board itself is usually not the same as the rise.
Recognising it
Look at the stair from the front. If every step has a closed vertical face between the treads, those are the risers. If you can see through between the treads, it is an open-riser stair.
In practice
- Consider a slight rake. A riser that leans back slightly gives the foot more room on the tread.
- Check risers on a creaking stair. A warped or shrunk riser can make the stair creak; a small glued block fixed behind the joint can stop it.
- Measure the rise on the treads, not on the board. Stair calculations use the distance from tread to tread.
- Check the rules for open risers. For dwellings in England, the guidance in Approved Document K is that the gaps in open risers should not let a 100 mm sphere pass through, so small children cannot slip through. Adding risers or riser bars is a common fix.
Common mistake: using the board height as the rise when designing or replacing a stair, so the stair calculation comes out wrong.
Related terms
- Riser height
- Stair tread
- Tread depth
- Open riser staircase
- Stair step formula
- Overhanging stair tread
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