by Mike Sloggatt
When I'm reviewing the prints for a remodeling job, one of the
first items I check for is the addition of new structural
beams, which always require plenty of manpower and extra work.
But prints don't always give you a clear picture of actual site
conditions.
Such was the case with a split-level home we recently
remodeled. To increase room size on the ground floor, the plans
called for the removal of a bearing wall (see Figure 1), which
would be replaced with a 15-foot-long beam made from a pair of
1 3/4-inch-by-14-inch Microllam LVL joists. The problem was
that setting this 14-inch-deep beam flush to the top of 2x8
floor joists would leave nearly 7 inches of Microllam hanging
down into the room. Not very attractive, in my book.
Figure 1. To open up the floor plan of a
split-level home, the author removed this bearing wall and
replaced it with an engineered beam. Matching the depth of the
beam to the 2x8 floor framing maximized headroom and allowed
the beam to be hidden by the ceiling finish.
Because the split-level had a ceiling height of only 7 feet 4
inches on the first floor, it wasn't difficult to convince the
homeowner that installing a shallower 7-inch-high beam would be
a better solution. Admittedly, our approach was more expensive
than cutting a pair of stock LVLs to size, as shown in the
original plan; but a beam designed to be installed flush with
the finished ceiling would result in an unobstructed ceiling
and make the room much more attractive.
A Better Beam?
Typically, a shallow 7-inch wood beam requires reinforcing with
a steel plate or I-beam to give it enough strength to span 15
feet. In the past, I've always hired an engineer to design
these wood-and-steel "flitch beams," then ordered the steel
from a local fabricator and assembled them on site.
But the installation of large beams — which involves
lugging around 350-pound plates and assembling them on a table,
then hoisting a 600- or 700-pound beam overhead — is a
daunting task with a small crew. At my age, I wasn't looking
forward to the process.
Convinced there had to be a better way, I decided to try a
prefabricated beam from the Better Header Co. (631/242-1975,
www.betterheader.com). I had seen this
company's product at a trade show and promised myself that the
next time I had to install a steel flitch beam, I'd give it a
try. I wanted to see if the system was any better than my
site-built approach.
To get a beam design that would work in my situation, I
provided the company with the length of the span, the width of
the structure above, and an estimate of all of the loads that
the beam would have to carry. (Sales are typically handled
through your local lumberyard.) I also provided a sketch of the
existing structure's cross section that showed the span of the
floor above, the location of a second-floor bearing wall, and
the ceiling above (see illustration).
To open up the floor plan in the basement of this
split-level home, a bearing wall was removed and replaced with
a steel-reinforced flush beam. A pair of temporary 2x4 walls
supported the floor system while the channel for the beam was
cut into the existing floor joists and the beam
installed.
The price for a delivered beam was $1,100. At first, that
seemed expensive, especially since I could purchase all the
components for around $850. But when I considered the
additional $200 for the engineering fee, and the two hours or
more we'd have to spend assembling and lugging around the beam
with four men, I decided that the prefabricated beam was the
better deal.
I was promised delivery to the job site within a week. But one
problem remained: This beam would be heavy. Built of three
13/4-inch-by-7-inch LVLs reinforced with two 1-inch-by-7-inch
steel plates, all bolted together, the beam would weigh nearly
800 pounds.
I needed to make sure that I was prepared to handle the load
when the beam arrived.
Supporting the Floor System
Delivery was scheduled for noon by boom truck. That gave us an
entire morning to prepare the site for installation. The
homeowner had already gutted the room, and a plumber had
relocated some pipes the day before. We had to work around a
few wires, but most would be relocated later by an
electrician.
To support the ceiling joists while we installed the beam, we
needed to build a pair of temporary 2x4 walls. In general,
temporary shoring should be built as close to the original beam
as possible. In this case, placing the temporary 2x4 walls 2
feet on either side of the existing bearing wall's centerline
would leave us with the 4-foot working area we'd need to
accommodate our jacks.
With only a floor load and attic above to support, I felt that
this 4-foot clear span wouldn't be a problem. But in more
complicated cases where there is a posted ridge or other
substantial load above, I always consult an engineer, who specs
out distances, connectors, and the proper removal
sequence.
After measuring, cutting, and laying out the plates for both
temporary walls, we went ahead and installed the first one.
(The other would have to wait until we had the beam
positioned.) We began by fastening our top plates to the floor
joists above, then positioned the floor plates directly below
and placed one stud under each joist. To ensure a snug fit, we
measured for each stud and then cut long by about 1/8 to 1/4
inch. If a stud still seemed loose, we ran a hardwood shim
under the bottom plate and beat it in.
We held everything together with 3-inch-long #10 deck screws
— two to three per stud connection — which would
make it easy to take everything apart afterward and reuse the
materials for other parts of the project.
Before loading the studs by removing the bearing wall, we ran
horizontal 2x4s to connect the studs at midheight. This kind of
lateral bracing helps prevent individual studs from bowing. We
also added a diagonal 2x4 brace at the end of each wall,
fastened at the top, middle, and bottom to help prevent bowing
or racking.
In addition, prior to removing any bearing structure, it's good
practice to measure and write down the distance from the floor
to the bottom of the existing joists in a number of places. I
wrote these measurements right on the joists next to the beam,
and used them later to determine whether the floor framing had
dropped from its original position after the job was
complete.
It's also good practice to go upstairs and make written notes
of any unevenness in the floor, cracks in plaster or drywall,
or problems with door swings and clearances, and to point them
out to the homeowner so you don't end up owning existing
problems. I also document these issues with a digital camera
prior to any wall removal.
With the existing conditions documented and one temporary
support wall installed and braced, we were ready to begin
demolition. Since the joists above ran continuously over the
bearing wall, we could remove the old bearing wall with only
one support wall in place (Figure 2). More typically, the
joists break over a center bearing wall, requiring two support
walls prior to demolition.
Figure 2. After building the first
temporary support wall, a carpenter removes most of the old
bearing wall. Had the floor joists broken over the bearing
wall, as is often the case, both temporary walls would have
needed to be in place before removing the old
framing.
As so often happens on the day of a big job, I was short one
man, so installation of the big beam was up to just me and one
helper. Fortunately, though, we were well-prepared. That
morning, I had rented two Hi-Jacks (Vermette Machine Co.,
800/348-6454, www.vermettlifts.com) from the local
tool-rental store. These freestanding jacks are capable of
lifting 500 pounds each up to a height of 10 feet (somewhat
less in interior spaces, where structures overhead may
interfere with the lifting mechanism), and are easily
transported and assembled on site.
I had also placed two furniture dollies outside on the
sidewalk, thinking we would have to drop the beam onto them and
roll it up to the house. But when the boom operator opted to
send the beam right through the front doorway instead, he got
no argument from me (Figure 3).
Figure 3. To get the 800-pound beam into
the house, the boom operator dropped one end onto a jack inside
and the other onto a dolly outside. The author and his helper
rolled the beam through the front door, then slid a second
dolly under the tail end and pushed the whole assembly the rest
of the way into position.
After we transferred the beam onto both jacks, we rolled it
into position. Then we assembled and braced the second
temporary support wall for the other half of the room (Figure
4). With the second wall in place, we removed the last section
of header from the old bearing wall.
Figure 4. Once the beam was in position on
the floor beneath the pocket, the second support wall could be
assembled. Lateral and diagonal bracing strengthened the
temporary walls and helped prevent individual studs from
buckling under load.
Cutting in the Beam Pocket
Next, we marked the location of the new beam on the floor
joists, centering it on the old bearing wall. The beam actually
measured almost 7 1/2 inches wide, plus I added an extra 1/8
inch for wiggle room, so we marked a 7 5/8-inch-wide channel to
receive the beam.
To get clean, straight cuts, we started our kerfs with a
circular saw and finished up with a reciprocating saw (Figure
5). Even though a cut line that wandered 1/4 to 1/2 inch
wouldn't be a big problem structurally, square cuts look more
professional, and they help justify the invoice later on.
Figure 5. After laying out the new 7
5/8-inch-wide beam pocket, the author's helper snaps chalk
lines (top), then uses a small square to mark cut lines on the
joists (middle). Starting kerfs with a circular saw (bottom
left) and finishing up with a recip saw produced clean,
straight cuts. The author set the recip-saw blade so that it
just barely cut through the 2x8 joist, and he gave the tool a
slight backward tilt to prevent the blade from wandering off
the cut line (bottom right).
After cutting the pocket, we cleaned up stray nails to make
room for the beam (Figure 6). We were careful to cut all metal
flush with the recip saw so that the beam wouldn't push up the
subfloor or finish floor when it was installed. And to
accommodate a few stray telephone wires, we cut out a short
section of the 1x6 subfloor to leave a 3/4-inch-thick chase
above the beam.
Figure 6. Before the new beam could be
raised into the pocket, any penetrating nails that might be
pushed up through the subfloor above had to be either cut off
or clinched over.
Installing the Beam
Once the pocket was prepped, we proceeded to jack up the beam.
The Hi-Jacks are stable and roll easily even when loaded, so
the beam didn't have to be perfectly aligned with the pocket
when we started lifting.
Because of their design, though, the Hi-Jacks couldn't lift the
beam all the way up into the pocket. To hoist it the last 6 or
so inches into place, we had to place cribbing between it and
the lift. We did this by raising the beam as high as we could
into the pocket (to keep it from rotating) and temporarily
posting one end, which allowed us to lower the jack on that end
and block under the beam with scrap 2-bys (Figure 7). After
using the same approach to install cribbing under the other
end, we were able to jack the beam fully in place, lined up
flush with the ceiling joists.
Figure 7. A worker uses 2x4 cribbing to
lift the beam above the level of the jacks' support columns.
Sections of the temporary wall's top plate were cut to make
room for the jack arms.
One common problem with site-built beams is bolt heads sticking
out just where a joist is sitting. But this header's recessed
bolts made it much less difficult to slide into position. Also,
the rollers on the jacks made it easy to position the heavy
beam precisely, even with the beam held up high.
With the beam in place, we installed tripled 2x6 posts below
each end of the beam to lock it into position, and then lowered
and disassembled the jacks.
To complete the installation, we fastened metal joist hangers
to all of the floor joists; using a Paslode Positive Placement
pneumatic nailer (800/222-6990,
www.paslode.com) made the job go a lot
faster (Figure 8).
Figure 8. The author uses a Paslode
Positive Placement pneumatic nailer to fasten the joist hangers
to the beam and floor joists.
In cases where the bottom of the joist sat flush to the bottom
of the beam, we notched the end of the joist to allow the
hanger to sit flush, too (Figure 9). Once again, the recessed
header bolts made installing the hangers much easier, because
they didn't interfere with the hangers.
Figure 9. Where the floor joists are flush
with the bottom edge of the beam, the author chisels out
notches for the joist hangers.
By rechecking the joist-height measurements I'd taken before
removing the old bearing wall, I could easily find out how
close the joists were to their original position. In this case,
the floor wasn't level to begin with, while the beam was laser
straight. Where joists were too low, I drove hardwood shims
between the plate and the bottom of the joist to raise the
joist until it was flush with the bottom of the beam; then I
installed the joist hanger.
Meanwhile, on the other end of the beam, the tops of some of
the joists were as much as 3/8 inch above the top of the beam.
Since my measurements for the finished floor confirmed that
nothing had moved, it was apparent that the sagging of the
original structure prevented the beam from going completely
flush with the existing framing.
Because the section above included a tile floor, I chose to
leave the joists as they were and deal with shimming drywall
rather than try to straighten out the sag and risk cracking the
existing tile floor.
Once all the hangers were in place, we removed the temporary
walls (Figure 10). The entire job took approximately 4.5 hours
and required two men. We paid $140 to rent the pair of Hi-Jacks
for the day, which was much less expensive than paying four
borrowed carpenters for 2 hours. And the jacks don't break for
lunch.
Figure 10. Once the joist hangers were
installed on one side of the new beam, the author removed the
temporary supporting wall.
Mike Sloggatt is a remodeling contractor
in Levittown, N.Y.