A Few Pole Building Terms
The following are a few of
the most common Pole Building
terms
used by builders and engineers.
Of course, if you come upon a
term you don’t understand that
is not in the glossary below, or
you
have other questions, please
feel free to call us anytime! |
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Backfill - Material
used to fill a posthole, typically concrete
or crushed gravel.
Cladding - The
metal exterior and interior coverings
fastened to the purlins and girts (see also:
sheathing).
Corbel
Block or Bearing Block - A
piece of dimensional lumber installed
vertically under the heel of a truss or
rafter and attached to the post with nails,
screws or bolts to provide vertical support
for the rafter or truss.
Diaphragm - A
structural assembly comprised of metal
cladding or wood sheathing fastened to roof
or wall framing with multiple fasteners
capable of transferring in-plane shear
forces.
Eave
height - The
height of the eave wall measured from grade
to the top of the top eave girt.
Eave
wall - The
wall on the side running perpendicular to
the main trusses or rafters.
Embedment - The
portion of the post that is buried in the
ground and backfilled with either concrete
or crushed gravel.
Gabled
roof - A
typical roof (the most common) sloping down
each side from a ridge running parallel with
the eave wall.
Gable
wall - The
triangular end wall of a gabled roof
building.
Gambrel
roof - A
roof with two slopes on each side of the
ridge, the lower slope being steeper than
the upper slope.
Girt - A
structural member spanning horizontally
between wall posts or columns to provide
structural support for posts and attachment
for wall cladding or sheathing. They can be
installed flat against the back of the post
or like a shelf and installed between the
posts (commercial style).
Heel - The
end of a truss or rafter that is attached to
a post or beam for support
Loads:
Dead
load - Loads
resulting from permanent loads due to
the weight of the building structure
itself or permanently installed
equipment & components.
Live
load -
Loads resulting from temporary loads due
to wind, snow, seismic, people and other
loads that may not be imposed
continually on the structure.
Monoslope - A
roof with a single slope from one side of
the roof to the other, also called a “shed
roof”.
O.C. - Stands
for “on-center”, specifying structural
member spacing with respect to each other
and measured from the center of the members
(i.e., 24” o.c.).
OSB -
Stands for Oriented Strand Board-Structural
wood panels similar to plywood but
manufactured from wood strands resembling
wood “patches” bonded via heat and pressure.
Outrigger - A
member that matches the purlin size and
grade placed perpendicular to purlins on top
of the truss top chord or rafter at the eave
wall post, and extends out past the wall to
provide support for the roof overhang.
Post or
Pole - A
vertical column typically providing
significant structural vertical and lateral
support. They are used in post frame
construction to transfer loads from main
roof beams, trusses or rafters to the
foundation. Posts are typically rectangular
and uniform in shape, while poles are
typically round (however both are used
interchangeably).
Posthole - The
hole in which the structural posts of a pole
building are embedded providing lateral
support for the building.
Post pad - The
concrete pad (typically 6” thick) at the
bottom of the posthole to provide vertical
support for the post and distribute the
vertical load to the soil.
Pressure
treated wood - Wood
that has been chemically treated under
pressure to provide resistance to damage
from rot, decay and insects.
Purlin - A
structural member spanning horizontally
between the truss top chords or rafters used
to support roof sheathing.
Purlin
block-Blocking
placed between truss top chords or rafters
that extend up to provide attachment and
lateral support for purlins on top of the
trusses or rafters.
Rafter - A
main roof framing member, typically
supporting a purlin or can directly support
roof sheathing depending on the building
configuration.
Sheathing - Structural
(or non-structural) panels used for roof and
wall covering. Sheathing is typically
plywood or OSB but can also apply to metal
sheathing (aka “cladding”).
Skirt
Board - The
bottommost pressure-treated wall girt next
to the ground at grade line providing an
attachment point for the bottom of the wall
cladding
Snow
drift - Additional
snow load usually on a lower roof, resulting
from additional snow blowing against a wall
above a roof, or snow sliding off of an
upper roof onto a lower roof.
Top eave
girt - The
top girt/purlin at the top of the eave wall,
providing attachment for the top of the wall
sheathing and also for the roof sheathing at
the top of the wall.
Truss - A
structural component (typically engineered)
assembled from smaller wood or steel members
and mechanical fasteners designed to carry
high loads across long spans, typically
utilizing a configuration of multiple
triangles.
Uplift - The
load on a building component resulting in an
upward force, typically from wind load or
from the ground in the form of groundwater
or frost heave.
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