DIYbanter - Basement window retrofit

On 12 May 2005 09:25:04 -0700, "Greg"
wrote:

I'm going to add a egress window to a room in the basement so that it
can be used as a means of escape in the event of fire. Since this is a
retrofit, I will need to cut the foundation for the 48x48 window. Code
requires the window be not more than 44" from the floor.

If I cut all the way up to the rim joist, I will need to put an I-beam
across the span to support the joists. What does code require on the
size of the beam that would span 48-56"? If I don't have to cut all
the way up to the rim joist, how much foundation above the window must
remain before I will need to reinforce the span?

1: I think the window that you are contemplating is bigger
than you strictly need. A 31.5" wide rough opening
should be more than adequate.

On the other hand, if you're going that far, it's not
all that much of a leap to just cut all the way down
to the floor, and put in a door and a stairwell.

2: You probably don't need an I-beam.
You should only need an I-beam if there's something
significant, like a post, coming down on that section
of wall. If there's any sign of extra blocking in
there already, then it's time to panic, and call a
professional.

Otherwise, if the wall in question is parallel to the
existing joists, just sister two treated joists to
the existing rim-board.

If the wall is perpendicular to the joists, pick
a different wall, or take enough headroom to
put lintel across under the rim-joist.

(Or: Prop up the joists-to-be-undermined with
a timberjack and a 4x4. Cut 32" off the ends
to give yourself room to work, sister that
section of rim-joist as before, and then
sister the cut-off joists on both sides,
attaching them to the new triple-header
with 4.5" hangers.)

--Goedjn