A quick review of the prints told me that this renovation was
going to be different. There would be the usual Hoboken, N.J.,
hurdles, of course — limited parking, virtually no
backyard access, and inconvenient curbside deliveries —
which would make delivery of materials for the home's new
garden-level media room a logistical obstacle course. But the
project also involved a unique challenge that would make things
even more interesting: We would be cutting an opening large
enough to accommodate a new 12-foot-wide, four-panel glass door
in a 12-inch-thick, 30-foot-high brick wall (see Figure 1). To
install a steel header for the door, we'd first need to shore
up 22 feet of brick masonry above the new opening.


Figure 1.As the
centerpiece of an extensive garden-level remodel, the new
four-panel glass door would open up the ground level to the
backyard, filling the dark room with natural light. First,
though, a 12-foot-wide rough opening needed to be cut in the
solid brick exterior wall of the Hoboken, N.J.,
home.
Opening a solid brick exterior wall always requires care.
Generally, our approach is to needle steel supports all the way
through the wall, fortifying them on both sides with temporary
girders and posts. But this particular door installation was
complicated by the fact that only the ground floor was being
renovated; with a finished kitchen located above the new media
room, drilling through the wall wasn't an option. The temporary
opening would extend above the kitchen floor joists, and we
would have to support the exterior wall from one side only.
Because the joists run parallel to the exterior masonry wall
and are pocketed into the side party walls, there was no need
to support them.
An Engineered
Shoring Plan
Though Axis Architectural Studio, of Englewood, N.J., and
Feller Design, of Hoboken, N.J., provided us with a fine set of
prints to work from, there was no shoring plan for supporting
the wall during construction. I enjoy a challenge, but I
elected to turn this problem over to an engineer.
There was a time when we felt it was our responsibility to
implement the plan as presented and, ultimately, assume all the
risk. But as our projects have grown in complexity, we've come
to recognize where our own area of expertise ends and that of
other professionals begins. Now, if we determine that
additional drawings are needed to build a project safely, a
clause in our contract allows us to commission them from the
appropriate professional. If the additional cost becomes a
factor, we'd rather walk away from the project than risk
creating an unsafe condition.
Structural engineer Rich Herschlag, of Turn-key Structural in
Easton, Pa., identified four 36-inch-wide load-bearing brick
"columns" within the exterior wall, each receiving loads from
the numerous door and window headers stacked above each other.
The left and right columns that were clear of the proposed
opening wouldn't need to be supported, but the two middle
columns would (Figure 2).
Figure 2.After analyzing
critical load paths and identifying the structure's main
load-bearing "columns" (shown in the drawing on bottom), a
structural engineer designed braces to temporarily shore up the
30-foot-tall, solid masonry wall during construction. Welded
from steel I-beams and bolted to poured concrete footings, the
four identical braces would support the home's masonry wall
from the outside without disturbing interior
finishes.
The plan called for four identical L-shaped steel braces
— which cost about $675 each to fabricate — to be
fastened to the brick wall from the backyard side, with each of
the middle load-bearing columns receiving two equally spaced
braces. Inserted 8 inches into the 12-inch-thick wall and
positioned roughly 2 feet above the kitchen floor joists, the
braces would support the exterior masonry wall without
disturbing the kitchen wall. Each brace would be bolted to a
footing so that it wouldn't kick out from the load (Figure
3).
Figure 3. Anchored to poured concrete footings, the four
cantilevered steel braces were designed to support vertical
loads of 9,900 pounds each without any deflection, so that the
solid masonry wall above the new opening wouldn't
crack.
Because we felt that concrete footings formed on the surface
also might kick out, we decided to bury the footings in the
ground to help anchor them. We used a transit to verify that
the top of each footing was level with the other (Figure
4).
Figure 4.To prevent the
braces from kicking out from the wall under load, the footings
were buried below grade. The author used a transit to make sure
the poured footings were level with each other.
While the concrete cured, we laid out the rough opening for the
new door. On the left side of the new opening (as viewed from
the backyard), we needed to remove a small window and close up
the opening with brick. Another window located entirely within
the rough opening would disappear after demolition for the new
door. The window on the far right was a different story: It
would be bisected by the rough opening, so we needed to remove
it and brick over half the opening. We started our brickwork
off the foundation wall and used brick ties on every other
course to assure a strong connection between the new brick and
the old.
To get the 400-pound braces into the backyard, we removed the
sash from one of the garden-level front windows and passed each
brace through, a task made easier by their L-shaped design.
With the braces temporarily set into position on the footings,
we marked their location on the faade. We were lucky
that the top of each brace fell 1/2 inch below a mortar joint,
which meant we'd need to do minimal shimming. Had the pocket
height fallen within a brick, we might have had to shim the
braces as much as 2 inches. In hindsight, it would have been
better to have approximated the pocket locations before pouring
the footings, chipped away the stucco to reveal the bricks and
mortar joints, and then determined an optimal footing elevation
with the help of a transit.