Renovation 4th Edition
Page 17
3-8d
ple, blunt-point nails are less likely to split wood
built-up corner studs
16d at 24 in. o.c.
than pointed nails because the blunt points crush
the wood fibers in their path rather than wedging
built-up girders and beams
20d at 32 in. o.c., along each edge
them apart. You can fashion your own blunt
points by hammering down a nail point.
* Uniform Building Code (UBC) content reprinted courtesy of International Conference of Building Officials
However, the blunt point reduces the withdrawal
(adapted from 1997 UBC Table 23-II-B-1).
friction on the nail shank.
Composition. Most nails are fashioned from
medium-grade steel (often called mild steel). Nail
composition may vary, according to the following
pilot hoLeS
situations:
Material nailed into. Masonry nails are
Whenever you need to avoid bending nails in
case-hardened. That’s also true of the special
dense wood, such as southern pine, or when
nails supplied with joist hangers and other
you’re worried about splitting a board by screw-
metal connectors. Do not use regular nails to
ing or nailing too close to the end, drill a pilot
attach metal connectors.
hole. there’s no absolute rule to sizing pilot
Presence of other metals. Some metals
holes, but 50% to 75% of the nail shank diame-
corrode in contact with others because of
ter is usually about right.
galvanic action (see “Galvanic Action” on
p. 83). Try to match nail composition to the
building materials
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teco
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naiLS
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When attaching metal connectors, wear safety
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glasses and use only the special nails supplied
by manufacturers, commonly called teco nails
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after an early manufacturer. they’re sometimes
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called hanger nails. these nails are harder and
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squatter than regular nails and are less likely to
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shear under pressure.
Specialty nails: 1. Simplex nail for roofing underlayment and thin foam insulation; 2. Copper
flashing nails; 3. Galvanized roofing nails; 4. Gasketed nail for metal roofing and some skylight
flashing; 5. Duplex nails; 6. Finish nails (the middle one is vinyl coated); 7. Furring nails for stucco
wire; 8. Ring-shank nail; 9. Stainless-steel nail color matched to wood siding; 10. Joist-hanger
nails (Teco nails); 11. Case-hardened masonry nail
metals present. The choice of nails includes
nailed down. For sheathing 1⁄2 in. to 3⁄4 in. thick,
aluminum, stainless steel, brass, copper,
use 8d nails (which are 21⁄2 in. long). Use 6d nails
monel metal, and galvanized (zinc coated).
if the sheathing is 3⁄8 in. thick or less. Nail points
Exposure to weather and corrosion.
should not protrude through the second piece.
Neither stainless-steel nor aluminum nails will
The workhorse of framing is the 16d common,
stain wood. However, stainless is expensive,
although 12d or 10d nails are good bets if you
and aluminum is brittle and somewhat tricky
need to toenail one member to another. Use 10d
to nail. Galvanized nails, which are reasonably
or 12d nails to laminate lumber, say, as top
priced, will stain only a modest amount where
plates, double joists, and headers.
the hammer chips the coating off the head.
When nailing near the edge or the end of a
Therefore, you should seal galvanized nail
piece, avoid splits by using the right size nail,
heads as soon as possible with primer.
staggering nails, not nailing too close to the edge,
Galvanized nails are also specified when
blunting nail heads, and drilling pilot holes. Box
framing with redwood or treated lumber, both
nails, which have smaller-diameter shanks than
of which will corrode common nails. If you’re
common nails, are less likely to split framing
installing costly redwood or cedar siding, use
during toenailing.
stainless steel, especially if you’ll be sealing
Pneumatic framing nails. When you’ve got a lot
siding with a clear finish.
of nailing to do, say, to sheath an addition, you
Holding power. Nails that are rosin
may want to rent a pneumatic nailer. As noted
coated, cement coated, or hot-dipped
earlier, it’s best to set air pressure so that nail
galvanized hold better than uncoated nails.
heads stop just shy of a panel’s face ply. Then use
Vinyl-coated nails both lubricate the nail shaft
a framing hammer to drive each nail flush. Many
as you drive it in (friction melts the polymer
pneumatic framing nails are vinyl coated to make
coating) and act as an adhesive once the nail’s
them hold well. And some pneumatic nail heads
in place.
are colored, so you know immediately which size
Sizing nails. Common sense dictates the size
you’re loading.
of most nails. Generally, length should be about
Pneumatic nails differ slightly from common
three times the thickness of the piece being
nails, however, so you may want to check your
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chapter 4
local building code before you rent a nailer. For
let the driver blade slip out of the slot when
example, pneumatic nailers load either coils of
torque is applied, whereas drive heads with cen-
nails (coil nailers) or nails aligned in diagonal
tered patterns completely surround the point of
strips (stick nailers). Both work well, but some
the driver tip, holding it in place. Among the
stick nailers accept only nails whose heads have
most popular drive heads are Phillips, square-
been partially clipped. (Clipped-head nails pack
drive, and six-pointed Torx®.
more tightly.) Clipped-head nails are rarely a
These days, screws are often engineered to
problem when nailing 2x lumber together, but
specific uses. Trim-head screws have small heads
plywood secured by the smaller nail heads is
like casing nails so they can be countersunk easily.
more likely to pull through under stress.
Drawer-front screws have integral washers so
In addition, pneumatic nail shanks are often
they won’t pull though. Deck-head screws are
thinner than those of common nails. In fact,
designed to minimize “mushrooming” of material
some pneumatic 16d nail shanks are roughly the
around the screw hole. Some structural screws
same thickness as 8d common nails used for nail- have washer heads with beveled undersides so
ing by hand.
the screws will self-center in predrilled hinges or
connector pla
tes.
screWs
Threads. Screw threads are engineered for the
Screws have revolutionized building. Thanks to a materials they join. Traditionally, screws for join-
flood of specialized screws, builders can now
ing softwoods are made of relatively soft metal
quickly attach, detach, adjust, and reattach
with threads that are steep pitched and relatively
almost any building material imaginable. This is
wide in relation to the screw shaft. Screw threads
especially important in renovation, when you are for hardwoods and metal tend to be low pitched
scribing cabinets or setting door casing to walls
and finer. (The steeper the thread pitch, the more
that aren’t plumb—jobs that require patience and torque is needed to drive the screw.) If you’re
repeated adjustments to position materials.
screwing into dense particleboard or MDF, pre-
drill and then use Confirmat screws, which have
heads. The increased use of cordless screw guns thick shanks and wide, low-pitched threads.
has made slotted screws almost obsolete. That’s
Many screws—especially structural screws—
because screws with traditional slot-drive heads
now feature self-tapping tips, in which a slotted
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A sampling of screws: 1. Structural screws long enough to join timbers; 2. Torx-head structural
screws with integral washers; 3. Hex-head structural screw; 4. Square-drive deck screw with two
different thread pitches; 5. Deck screws; 6. One-way screw; 7. Galvanized drywall screw;
8. Standard drywall screws; 9. Square-drive sheet-metal screw; 10. Stainless-steel square-drive
flathead screw; 11. Stainless-steel square-drive trim screw; 12. Brass Torx-head trim screw;
13. Concrete screws
building materials
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screw tip drills its own pilot hole. Another inge-
structuraL screWs
nious design is a W-cut thread in which the
Structural screws such as Simpson’s SDS screws
threads nearest the tip are serrated like tiny saw
are so strong (they’re engineered to withstand
points, so they cut through wood fiber as they
seismic loads) and so convenient that they’ve all
advance. Such self-tapping features make it
but replaced nails and bolts for joining large
easy to drive in screws, without compromising
framing elements such as posts and beams.
holding power.
Thanks to their self-tapping points, SDS screws
There are even screws that cut into concrete.
shorter than 6 in. generally don’t need predrill-
Granted, you need to use a hammer drill to
ing, although that’s still a good idea when install-
predrill an exact pilot hole, but once the pilot is
ing 10-in. or 12-in. giants. Because structural
drilled, you can use a 12-volt or 18-volt cordless
screw diameters are somewhat smaller (1⁄4 in. is
screw gun, a standard 1⁄2-in. screw gun, or an
typical) than bolt diameters, you typically need to
impact screw gun to drive the screw the rest
use more screws per joint, but the screws drive
of the way. The threads grab the concrete and
easily with a right-angle drill or a large screw
hold fast; the trick is not overtightening and
gun. And once seated, the screw’s wide, sharp
breaking screws.
threads and huge shear strength combine to cre-
Coatings. Coatings matter most on screws used
ate a joint that won’t be pulled apart.
outdoors or in high-humidity areas. Although
To renovators facing tight spaces or limited
galvanized screws do resist rusting and are rela-
access to framing members, however, conve-
tively inexpensive, don’t expect them to last much nience is the bigger story. In many cases—when
more than 8 to 10 years on a deck—fewer if used
adding a deck ledger, doubling up timbers in a
near saltwater. GRK Fasteners™ promises
crawlspace, securing stair carriages to a stair-
Anchors and bolts for light loads.
“25 years in most applications” for its Climatek™
well—there’s access on one side only. You can
From left: plastic anchor with
coated screws. Makers of epoxy-, polymer-, and
screw, molly bolt, toggle bolt,
drill a hole for a bolt, but how do you attach and
and drive anchor.
ceramic-clad screws offer varying life spans.
tighten the nut on the other side? You don’t. But
The king of exterior screws is stainless steel—
drive in structural screws from one side and
expensive, by far the most corrosion resistant,
you’re done. So tying posts and beams to existing
and the only suitable screw to prevent stains after framing is no longer the bugbear it once was.
attaching cedar or redwood.
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Wood construction connectors (contractors generally refer to them by their Simpson catalog numbers): 1. H2.5, H4,
and H8 hurricane ties; 2. L90 reinforcing angle; 3. LS70 skewable angle (bend one time only); 4. A35, A35F, and A34
framing angles; 5. U410 face-mount hanger for 4x10 beam (or double 2x10s); 6. LU28 face-mount hanger for 2x8
joist; 7. H10 and H1 hurricane ties
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chapter 4
Bolts
Bolts are used to join major structural members,
although with the advent of structural screws,
the differences between the two are blurring. In
zzzzzz simpson top-Flange Hanger
general, machine bolts and carriage bolts have
nontapering, threaded, thick shanks. Some bolts
are more than 1 in. in diameter and longer than
2 ft. Allthread (threaded) rod comes in lengths up
to 12 ft. and can be used with nuts and washers
at each end. Carriage bolts have a brief section of
These top-flange hangers quickly
square shank just below the head. Lag screws
align the tops of joists to beams
(also called lag bolts) have a hex head, but the
or headers. Hangers are available
lower half of the shank tapers like a wood screw.
for both solid-sawn lumber and,
as shown here, I-joists. Also nail
WaLL ancHors
bend-tab flanges into the bottom
flanges of I-joists to stiffen them.
Wall anchors employ small bolts or screws to
attach light to medium loads (towel racks, mir-
rors, curtain rods) to drywall and plaster walls.
None is designed for structural use. With the
exception of drive anchors, most require a pre-
drilled hole, and all expand in some manner so
they won’t pull out easily. Molly bolts, drive
anchors, and toggle bolts are best for attaching a
light load to hollow walls. Wedge anchors, on the
other hand, expand in solid masonry walls.
<
br /> Wood construction connectors
Wood construction connectors are commonly
called Simpson Strong-Ties® after the company
that popularized them. For a complete overview
of available connectors from Simpson, go to
www.strongtie.com. Professionals swear by these
ingenious connectors for three main reasons:
They offer wood-to-wood connections
superior to most traditional construction
methods. For example, unlike toenailing,
metal connectors are unlikely to split lumber
ends or loosen under stress. These galvanized
steel connectors are strong and durable.
They greatly strengthen joints against
earthquakes, high winds, and other racking
forces. They can tie rafters to walls, walls to
floor platforms, and the substructure to its
foundation.
Straps, ties, and angles. Clockwise, from lower left: T-strap (post-to-beam connector), SST22
Most can be attached to existing framing,
light-gauge strap, ST6224 (24-in.) strap, MST24 heavy-gauge strap, twist strap, and heavy-gauge
a great boon to renovators, and in many cases
L-straps.
steel connectors are the only cost-effective way
to bolster the existing structure and tie
additions to the original structure.
Joist hangers are indispensable in renovation
when you want to add joists but can’t end-nail,
either because access is limited or because
you’re using engineered lumber, which is too
thin in cross section to end-nail successfully.
(Sawn-lumber joists and I-joists require different
building materials
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hangers.) There are joist hangers for single joists,
double joists, 4x10 beams, joists intersecting at a
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45° angle, and so on. You also have the choice of
face-mount or top-flange hangers. Top flanges
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are popular because they effortlessly align the
tops of I-joists with the top of a header or beam.
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Strap ties come in myriad shapes—tees, right
angles, twists—but all help keep joints from pull-
ing apart. Install flat strap ties where wall plates
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are discontinuous or where rafter pairs meet at
the ridge. Strap ties also keep floor platforms
from separating, much as shear walling does.
Hurricane ties, or twist straps, have a 90° twist to
join rafters to top plates, thereby fighting the ten-
dency of roofs to lift during a strong crosswind.
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