I put the technical data at the end of this email.
I'll give you the Blah, Blah, Blah first.
I tore out the old interior staircase from the
1st to 2nd floor in my house. The old staircase
had 2 stringers.
I cut 3 stringers and when I put the middle
stringer in it severly limits the head clearance
when I go down the basement.
Because of this, I would like to omit the middle
I'm about to screw and glue and I've
asked everyone I know what to do and
I get conflicting opinions. If some of my
advisors wouldn't throw in comments
about the decreased weight capacity
of the staircase, that 3rd stringer would
already be in the coal stove.
Location: Interior 1st to 2nd floor
Stringer Length: 14 feet
Stringer Lumber: 2x12 pine
Tread Thickness: 1 inch
Tread width: 31 inch
Tread Depth: 10 inch
Building Inspection: No
Is this a bad idea? Is 2 stingers enough for a
stairway 31 inches wide?
Hallo, Richard ,
Stringer Lumber: 2x12 pine
The Stringer Length: 14 feet has much more influence on the necessary
dimensions of the stringers than the tread with, if You only make the
treads thick enough.
Tread Thickness: 1 inch by Tread Depth: 10 inch will carry most
people. To my feeling, an educated guess based on a rather similar
stairs in my house, the deformation of the tread could be enough to
produce a noise a the joints when You use the stairs. A bit thicker,
1.5 Inches or at least 1.25 would be welcome.
With Tread Thickness 1.5 Inches I am rather inclined to take only 2
stringers, but they need to be thick enough. A cursory calculation
affirmed this by far. NO GUARANTEES! I have no inclination to end in
front of an American court.
There is however another problem: Beams that are much higher ( 12 '' )
than thick ( 2 '' ) want to lay on the side. You have to make sure that
the stringers remain in the upright position. In several old houses I
have seen the screwed to the adjacing wall.
But do not inhibit the deformation due to seasonal changes in moisture.
Invent a sort of clamp or drill bigger holes into the stringers than
the bolts would need and use washers.
To make it real clear or just for the fun of it: mail me at
Greetings and good luck rh ,
a long time ago engineer
for mechanical resistance (stress and strain)
The bottom of the new staircase is above me
when I walk down the basements steps.
Two of the stingers straddle the basement
opening. The third, runs right down the center
and subsequently above my head when I go down
I took the first responders advice....sort of...I
put the third sringer in but moved it off center..
Are you using risers? If so, they add quite a bit of stiffness to the
treads, especially if you nail or screw the riser into the tread below.
Also, you could use 2x treads. Get yourself some doug fir 2x12's.
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