Supporting a Quarter Turn Staircase
 

Hi Everyone,
I'm a big fan of the site, but this is my first post, so please go
easy on me. Disclaimer: I am going to have the following
professionally done, but I just want to know enough to have an
intelligable conversation with the contractor.

I want to remove a wall underneath a quarter turn staricase. There
are only 4 steps from the landing to the second floor and there is a
point load where the stairs meets the 2nd floor on the left side of
the tread (the right side is on a bearing wall. The joists are 2x8
(16"o.c.) and span 16'. The point load is only 3' (tread width) from
the bearing wall. If I have the joist trippled, will it be able to
support the staircase at the point using a joist hanger? Would a
wood I-joist be better? What type of questions or concerns should I
be worried about?

Thanks kindly,

Matt

mattkelley wrote:

Hi Everyone,
I'm a big fan of the site, but this is my first post, so please go
easy on me. Disclaimer: I am going to have the following
professionally done, but I just want to know enough to have an
intelligable conversation with the contractor.

I want to remove a wall underneath a quarter turn staricase. There
are only 4 steps from the landing to the second floor and there is a
point load where the stairs meets the 2nd floor on the left side of
the tread (the right side is on a bearing wall. The joists are 2x8
(16"o.c.) and span 16'. The point load is only 3' (tread width) from
the bearing wall. If I have the joist trippled, will it be able to
support the staircase at the point using a joist hanger? Would a
wood I-joist be better? What type of questions or concerns should I
be worried about?

I can't envision precisely what you're situation looks like from the
description but...the thing I think you'll need to be careful about will
be the reaction force on the other end of the joist which will now be in
uplift (probably w/ quite a long moment arm) owing to now having a
cantilevered load...

I can't envision precisely what you're situation looks like from the
description but...the thing I think you'll need to be careful about will
be the reaction force on the other end of the joist which will now be in
uplift (probably w/ quite a long moment arm) owing to now having a
cantilevered load...

That shouldn't a problem for stairs. If the thrust at the
top is perpendicular to the joist then the regular blocking
between joists and the plywood subfloor are pretty good at
transmitting/resisting that load.

Goedjn wrote:


I can't envision precisely what you're situation looks like from the
description but...the thing I think you'll need to be careful about will
be the reaction force on the other end of the joist which will now be in
uplift (probably w/ quite a long moment arm) owing to now having a
cantilevered load...

That shouldn't a problem for stairs. If the thrust at the
top is perpendicular to the joist then the regular blocking
between joists and the plywood subfloor are pretty good at
transmitting/resisting that load.

IF is the operative word here...