On Sep 15, 1:49*pm, Jules
wrote:
On Tue, 15 Sep 2009 04:44:21 -0700, geraldthehamster wrote:
My first floor joists are 7in x 2in, at 400mm centres. They span about
2.4m. Counting from one side of the room, the first joist is 3in from
the wall - if I remove the second joist, to create a stair well, in
principle does the third joist, which is now at the edge of the stair
well, need to be doubled up, and if so why?

Speculation follows, IANASE etc. :-)

Is a vertical support at the top of the stairs running to the floor below
an option? Depends what the implications are of transmitting load to
that floor below, but if it's solid beneath I suspect that'd do the
job.

Presumably some load on the floor is spread to the walls 'sideways' at
right-angles to the joists, so cutting out a big hole for stairs
does weaken things a bit, but by how much I'm not sure.

(Interesting question, anyway - I'm thinking about putting in some proper
stairs for the first floor in our barn, so would have the same
issues)

cheers

Jules

Yes, I'm interested in the theory as well as the practice. I can see
that a new stud wall built onto what is now the "edge joist" might
necessitate doubling up to support it, but is it necessary in any case
because the joist is at the edge? If so, I don't understand the
physics ;-)


Regards
Richard