As a framing and finish subcontractor working in the suburbs
north of New York City, I get my share of interesting
remodeling projects. One recent favorite was a two-story
addition on the back of a conventional two-story colonial. The
first floor of the addition doubled the size of the existing
kitchen; upstairs we added a new laundry and a master bath
complete with a 6-foot whirlpool tub.
Generally speaking, the framing was straightforward, but as
with any remodel there were complications. The biggest
challenge was the nearly 20-foot-wide opening we had to create
to connect the first floor of the new space to the existing
kitchen. Because the addition is on the eaves side of the
house, I had to temporarily support the second floor and roof
loads while I prepared the opening and installed a new
Providing Temporary Support
Looking at the plans, I knew we'd need a temporary stud wall
inside the existing space to shore up the house while I
installed the W8 x 48 I-beam header specified by the architect.
To leave working room, I wanted to keep the temporary wall
about 3 feet inside the exterior wall (see Figure 1).
Figure 1.Before opening up the exterior bearing
wall, the author provided temporary support for the
second-floor and roof loads with a temporary stud wall on the
inside and angled supports on the outside. The interior support
wall was sheathed and insulated to provide weather protection
for the house, which was inhabited during the
Concerned that this might create an unstable cantilever, I also
decided to install diagonal supports on the outside —
like the kind of temporary supports you'd use to hold up a
porch roof while you rebuilt the floor. This meant building a
temporary wall under the floor of the addition to provide a
continuous load path for the diagonal braces to the
In building the temp wall on the inside, I decided to cover it
with 1/2-inch plywood and install fiberglass batts to give the
homeowners — who were living in the house during the job
— some weather protection.
Luckily, the GC took care of removing the asbestos siding from
the area where the addition was going; to get started, we just
had to pull off the sheathing and remove an existing window and
door. Before installing the diagonals, we fastened a temporary
2x10 ledger above the new opening, using 1/2-inch lag screws.
We predrilled the studs to prevent splitting, and used plenty
of 16d commons as well.
After placing the 2x8 diagonals, we attached a second ledger
underneath to prevent them from slipping and to contain the
inevitable splits at the notches (Figure 2). We nailed them off
at their bases to a plate secured to the floor framing.
Figure 2.A 2x10 ledger fastened to the studs with
1/2-inch lag screws serves as an attachment point for the 2x8
diagonal braces (top). A second ledger beneath the top end of
the braces keeps them snugly in place and helps prevent
splitting. A sheathed, insulated 2x4 wall on the inside picks
up the second-story floor loads (bottom).
Prepping the Opening
The day before we were to install the header, I made a trip to
my steel fabricator to double-check measurements and fasten a
wood nailer for joist hangers to the web (Figure 3). To be on
the safe side, I decided to use pressure-treated material for
the nailers in case condensation ever forms on the cold
Figure 3.A sandwich of pressure-treated lumber and
plywood bolted to one side of the I-beam provides a nailer for
joist hangers (top). Knocking the corners off the 2x8 allows it
to sit tight to the I-beam's web (bottom).
Meanwhile, back on site, members of the crew cut out the
opening in the exterior wall and removed the band joist in
preparation for the I-beam. When they were doing this, they
noticed that the existing second-story floor joists were 2x8s
— not 2x10s as the architect had assumed. That meant the
81/2-inch-deep I-beam wasn't going to sit flush with the bottom
of the existing framing. To gain some additional clearance, we
cut away the 5/8-inch subfloor above the header (Figure
Figure 4.After determining that the 8
1/2-inch-deep beam wouldn't fit within the home's existing
floor system, the author used a Fein MultiMaster to remove the
subfloor for an additional 5/8 inch of clearance (top). Here,
the opening is ready to receive the beam (bottom).
A quick phone call to the steel fabricator alerted him just in
time that the columns would need to be 5/8 inch longer than the
Even with the subfloor cut out, the beam was not going to
disappear into the framing. Still, it was close enough that
adding strapping to the existing kitchen ceiling would allow us
to create the flush ceiling the architect had planned.