I've been planning a bonus room addition to my house for years. This
will require the installation of a stairway from the first floor to
the new room. When I designed the addition several years ago, our
building code specified a minumum tread depth of 9 inches. I was just
able to fit the stair into the plan with about 10 inches to spare.
Construction is about to commence, and I just learned that we have
adpoted the 2006 code, which specifies the minum tread depth at 10
inches. Now my stairs won't fit in the space allotted. I cannot move
the top of the stair more than the 10 inches because there is a
structural beam in the way. The bottom of the stair ends at an
interior wall which will get a new door. Can I place one tread on the
other side of the door, moving the door opening up by the height of
one riser? Do I need a landing? I hope not, because the foyer on the
other side of that wall is not big enough. I'll put a call in to the
inspector this afternoon, but I'm curious as to how others have solved
Thanks in advance,
Having a door in the middle of the staircase certainly isn't allowed
by the building code. You can't have a door at the bottom, either. A
door at the top is allowed for an interior residential staircase as
long as the door swings out over the landing.
Perhaps you could omit the door at the bottom of the staircase and
just have a door at the top, in the new space?
It will accept 8' 11" for total rise and total run if you choose the
"Use Total Run" radio button in the box under the "Calculate" button.
What it _won't_ do is let you use 10" for a step rise. I'm still
suspicious that someone gave you faulty info. A typical stair tread has
a rise of 7 1/2" to 8".
The original plan calls for a kneewall on one side of the stair in the
bonus room. There is no room for a landing or turn in the stair.
So it looks like my options are:
1: Leave the door out completely.
2: Fully enclose the stair at the top so that a door can be installed,
swinging into the bonus room.
Either way, the lowest stair tread will protrude into the foyer.
Thanks for all the replies. If I've missed a potential soluiton,
please let me know.
Personally I think this is the only option...
If you can get that past the building inspector (I'm not saying you
can't!) it would be one awkward door. Odds are the inspector will want
a landing at the top even if the door swings into the room. (and a
larger landing if it swings towards the stair.)
My first point of negotiation will be to see if the inspector will
allow 9-13/16" deep stair treads. The door at the top should be fine,
because I see it done all the time around here. We'll see what he
Here are a couple of old carpenter truisms:
Rise + run should = 17 to 18
Rise + rise + tread should = 25
Good comfortable normal stair 7 rise, 11 tread
Your R+R at 7 3/4 should use a tread of 9 1/2. Some inspectors
are thoroughly stuck on a full 12" tread, measured nose to nose.
I would be more concerned about the inspector not accepting a 7
3/4 rise. I think the current code book maximum is 7 3/8.
I spoke with my inspector last night. He said they still allow 9"
deep treads, so the stair will fit. I asked about having a door at
the bottom of the stair, and he said as long as there is 6'8" of
headroom above the first stair nosing it wasn't a problem. I guess it
pays to ask.
Thanks to all who replied.