Putting trusses up successfully depends on a few easy
routines. Over the years, I’ve developed several
techniques that I use on all my truss jobs, regardless of
whether they’re on a huge production tract or a single
custom home.
Doing prep work early on is where you can save the most time
on a truss job. Although a truss roof can’t go up till
the trusses are delivered, there’s a lot you can do while
you’re waiting for the load. The real benefit of prep
work is that most of it can be done on the ground where the
work is both safer and faster.
Layout and Blocking
The
first step should be to lay out the interior wall top plates
with reference marks that will ensure the proper placement of
the floating truss clips later on. This only takes a few
moments when the building is not covered by a load of trusses.
Don’t bother laying out the exterior walls because the
eaves blocks will automatically do that for you.
Simultaneously, another carpenter can cut backing for
ceiling drywall that will later be nailed flat to the top
plates. By quickly scratching the truss layout on the floor,
you can identify the walls that need backing. I prefer to use
2x6 backing where possible, and only use 2x4s when a truss
chord runs down the middle of a wall or along one side. A good
trick for measuring lengths is to spread the stock alongside
wall partitions and cut it in place, allowing a few extra
inches to run past the corners.
Once all the backing is cut, you can save time by
temporarily hanging the material where it can be reached later
on when standing trusses. Backing, eaves blocks, and outriggers
with at least one nail started in them can be hung from nails
placed on the inside of the exterior walls, a few inches down
from where the stud butts the top plate. If you are using metal
eaves vents, hang them up as well so they can be put in place
as you stand the trusses. The metal flange on the ends is thin
enough to allow it to be slipped in place between the two top
plates. The important thing about hanging materials is to make
sure that the pieces are completely out of the way below the
plate line.
With large spans with no center walls to stand on when
raising trusses, it’s a good idea to build a catwalk. The
most common areas for catwalks are in the garage and the living
room. Keep the highest point flush with the top plate or just
below. I prefer to use a flat 2x6, held on each end by a cleat
fastened to the wall, with 2x4 legs nailed on for mid-span
support. Catwalks should be plenty strong for safety’s
sake.
Prepping Truss Braces
I
use 1x4s nailed to the top chords to secure trusses as they are
tipped up to their proper spacing. Other 1x4 bracing, called
"lacing," is nailed in permanently at locations specified by
the truss manufacturer’s engineering plans. Truss
installers have to follow the manufacturer’s plans
exactly to ensure that a truss roof system performs to its
designed capacity.
To save time, I gang together as many pieces as I think
I’ll need for the top boards and the lacing, and lay them
out all at once. This usually works out to about five to six
times the length of the building. I use either 12- or 16-foot
lengths because 8 and 10 footers are too short and pieces
longer than 16 feet are too hard to handle. I mark the outside
edges of the truss layout on the outer ganged pieces and
transfer marks to the other pieces with a straightedge. To
designate which side of the layout marks the trusses should go
on, I run keel lines parallel to the pencil lines to represent
the leading edges. This avoids the hassle of making hundreds of
small Xs.
Fill package.
On most
production jobs, the truss manufacturers send out a "fill"
package with each truss order that contains cut-to-length eaves
blocks, outriggers, and barge rafter stock. Smaller job-site
fill packages might not include outriggers or barges. In these
cases, they should be cut beforehand.
Once cut or removed from the fill package, it helps to mark
and prep all the outriggers at one time by ganging them
together and marking them at 221/2 inches and 24 inches from
one end. This locates the end truss relative to the butt end
that will be attached to the first interior truss. The
remainder provides the extension for the overhang. Set a
16-penny nail in the face of the marked 11/2-inch space. Then
set a toe-nailed 16 at the end that will butt into the
receiving truss (the longer side). Hang the riggers up by
hooking these nails onto other nails tacked at a convenient
height along the gable-end wall.
Sway braces.
At this
time, I also cut a sway brace for each end. These braces run
diagonally from the end wall top plate to the ridge block of
the third regular truss, and are used to plumb the first few
trusses at each end. A 10-foot 2x4 works well for a typical
6-foot-tall truss. I prep the sway brace by cutting a 45-degree
angle on one end, then hang it on the interior side of the end
wall just below the top plate where I can reach it later.
Loading the Trusses
When
the trusses arrive on the site, there’s still some ground
prep work to do, but first the trusses have to be loaded on the
building. Crane operators will put the trusses wherever the
crew tells them to. In production situations, trusses
aren’t doled out one at a time. You’ll get bundles
dropped on the plate line as quickly as the crane operator can
swing the boom, empty the load, and head back to the plant to
load up for another delivery.
One thing to be on the lookout for, especially on the
bustling tracts, are end-truss studs that have been knocked
loose in a busy lumberyard. Once in the air, a bundle that
contains a damaged end-truss can drop loose studs that fall
like spears.
Loading strategy.
The
length of the building and the size of the trusses determine
the best loading order. A truss that spans 30 feet and has a
4/12 pitch will only be 5 feet tall. Trusses in this ballpark,
say 5 to 7 feet tall, are fairly easy to maneuver. I like to
spread these out from one end of the building to the other
before raising them (see Figure 1).

Figure
1. Small trusses (under 30 feet) can be spread evenly
along the walls. The author prefers to stack larger trusses in
bundles, so he only has to move them once.
But if trusses are larger, say a 50-foot span with a 6/12
pitch, it ends up being too hard to move them twice. If there
is room, I’d rather load these so that they can be pulled
off a bundle and stood one at a time.
However the trusses are loaded, I always make sure the end
trusses will be in a position that allows them to be notched
for outriggers before being stood. Climbing up an already
raised gable truss, with saw in hand, to cut out spaces for
outriggers, is an excruciatingly slow job and is to be
avoided.
After all the truss bundles have been loaded on the plates
and the truck is gone, it’s time to break into the fill
package again to prep the eaves blocks. I place them inside the
house, butted up on edge along a wall. This aligns the blocks
so that a toe-nail can be started into each one. I set the
angle of the nail so that it will come out of the block with
plenty of nail going into the truss. If set too flat, the
blocks will fall off the nails when you try to hang them on the
exterior walls. If set too steeply, the nails will not
penetrate the trusses sufficiently.
The last preparation task to take care of is to precut the
barge rafters. The length can be measured off a truss, and
stock pieces can then be crowned up and cut plumb. It helps to
nail a ridge block on one of each barge rafter pair. This block
should be cut about 1/8 inch short to compensate for the truss
plates. I also like to tack a small handful of 16-penny
galvanized nails onto the top edge of the barge. This saves
groping for stray galvies later on when nail bags are full of
16-penny and 8-penny sinkers.
Upright end-truss
braces.
Before standing any trusses, temporary 2x6
braces are nailed vertically near the center of the gable-end
walls to hold end trusses close to plumb while nearby trusses
are raised. Avoid placing these uprights too close to the peak
where they will get in the way when installing barge rafters.
The 2x6s need to be long enough to reach from the bottom plate
of an end wall, up along a stud, to the top chord of the end
truss after it’s raised.
If the trusses are over 8 feet tall, a separate upright
brace is necessary on each side of an end truss. For tall
trusses, you’ll have to position upright braces farther
from the center where you can still reach the top chord.
Once the uprights are in place, spread out the bracing
pieces that were marked earlier. Lean the lacing high enough on
the gable walls so you can easily pull them up into the truss
cavities. This way they can be scattered into their locations
as the trusses are stood, which is easier than fighting them
into place afterwards. The remaining braces should be spread
around the building exterior so that they lean a few inches
below the plate where they won’t interfere with spreading
the trusses or walking on the plate.
Outrigger notches.
With
saws and nails placed up within reach of crew members on the
top plates, it’s almost time to spread and tip trusses.
The final prep work involves notching the end trusses to accept
outriggers for the roof overhang. One foot down from the peak
is a good measure for the top outrigger on each side. The rest
are located 4 feet on-center down from these top notches
(closer for tile roofs, to prevent sagging). I also like to
place one close to the eaves to provide extra support for the
barge rafter, especially when no fascia board is being used. At
this point, I prefer to nail at least the upper outriggers into
place because they can be very hard to reach later on.
Before tipping a notched end-truss into place, I start
16-penny toe-nails along the bottom chord at 16 inches
on-center. That way, when the truss is raised, I only have to
lean over and finish driving the toe-nails as I adjust the
chord flush to the edge of the wall with my foot. Raising an
end truss often involves pushing on the truss studs. To be
safe, it is vital to check that the studs are solidly attached
before you begin to stand the truss. As a precaution, you can
take this one step further and toe-nail the studs with
8-pennies to beef up the connections.
While one person is holding the truss upright, another
positions it by moving it back and forth until the heel
intersection of the bottom and top chords lines up with the
outside edges of the wall. Once adjusted to position, tack the
upper chord to the upright brace and nail the bottom chord to
the plate (Figure 2).
| Figure
2. With the upright braces in position and
toe-nails started along its bottom chord, an end
truss is tipped into position and nailed off. On
taller trusses, the author preinstalls the top
outriggers to avoid later hassle. |