What's An Open Riser Staircase?
You can see in the
picture above that there are no wood stair risers on the staircase in
the picture above. This is what most people would refer to as a set of
stairs with open risers. Most building codes give you the impression
that the days of an open riser stairway are numbered.
For most private residences or single-family homes, you're allowed to
have open risers, but they will fall into the
4 inch round sphere rule.
In other words, a 4 inch round sphere can't pass through the riser areas
located throughout the entire stairway.
If you are using a stairway for a building exit, you
will need to close the risers. Make sure that you use the correct
building materials when closing risers. I worked on a job one time
where I needed to use a minimum of 1 1/2 inch thick lumber to close the
stair risers. This provided the stairway with a one hour fire protection
rating.
Attention: Don't forget to check with
your local building department to verify any building codes on this
website. This information could be incorrect or outdated. Building codes
are updated regularly and to some building departments have different
interpretations for certain building codes.