3 b 'J'J' 'JI ll Bulletin 213
Construction of Pole-Type
Clear Span Buildings
R. A. Bucklin and A. R. Taylor
Florida Cooperative Extension Service / Institute of Food and Agricultural Sciences
University of Florida, Gainesville / John T. Woeste, Dean for Extension
CONSTRUCTION OF POLE-TYPE
CLEAR SPAN BUILDINGS
R. A. Bucklin and A. R. Taylor*
A clear span pole building is a structure that can economically
satisfy many needs. Pole-type buildings range in size from simple
10-foot x 12-foot shelters to large, clear span buildings 60 feet wide
and several hundred feet long. A pole building is constructed using
pressure treated wooden poles set in the ground. Pole-type buildings
are easy to construct and often cost much less than buildings built
with other methods of construction.
ROOFVERTICAL BRIDTRUSS PURLIN GIRIDGE
POLE TO TRUSS
(KNEE BRACE) EAVE
BOTTOM CHORD BRACING POLE
(RAT RUN) SPACING
Figure 1. Typical pole building
Choose the building site carefully. Site selection determines how
useful and efficient the building will be. The ideal site is well drained,
nearly level and convenient to other buildings. Decide on the floor
grade when laying out the building. Make the floor high enough to
drain water away from the building and not allow it to stand in
driveways or doorways.
Consider fire safety when locating buildings. If the building is 15
feet or higher, leave 75 feet between buildings to fight fires. Lower
buildings need less space between them, but adequate space must
be left for easy access by fire fighting equipment.
Locate all buildings for working ease. Consider the work routes
of both personnel and machinery as you plan the building. Plan for
* R. A. Bucklin is Assistant Professor and A. R. Taylor is Engineering Services Coor-
dinator, Department of Agricultural Engineering, IFAS, University of Florida,
possible future expansion without the loss of time and materials.
Don't block the ends of storage and livestock buildings with perma-
nent buildings such as milk houses, silos or feeding facilities. You
can easily remove end walls and add sections to the building if you
leave room for expansion.
If you want an open building, leave it open on the south or east.
This will keep the rain out and provide shelter from the north wind.
Install gutters and down spouts as needed.
Environmental factors must be considered if the building is to pro-
vide shelter for humans or livestock. Orient the long axis of the
building in an east-west direction to reduce the solar radiation load
on the occupants during the summer months. Provide an eave height
of ten to twelve feet, a continuous ridge vent, and a roof slope of
at least 3 in 12 to promote ventilation. Consider the use of insula-
tion between the roof sheeting and purlins to reduce the radiant heat
Estimates must be made of the maximum loads expected on the
structure. Loads affect the size and spacing of structural members,
the design of the joints and the design of the foundation. University
of Florida plans are designed for a roof live load of 15 psf (pounds
per square foot) plus a dead load of 5 psf. The 15 psf live load is based
on the load from an 85 mph wind. The 5 psf dead load is based on
the weight of corrugated steel roofing. This gives a total roof load
of 20 psf. In other sections of the United States, where snow and
ice loads are important, higher values must be used.
The total load on a truss varies with the truss spacing and truss
span. Table 1 lists total truss loads in pounds for truss spacings and
truss spans used in Florida Plan Service designs.
The truss load in pounds per foot of span varies only with the truss
spacing. Table 2 lists truss loads in pounds per foot of span for a
20 psf total load and common truss spacings.
Truss Spacing Truss Load
Table 2. Truss load in pounds per foot of span for common truss spacings
*Loads are calculated for a 20 psf total load.
When ordering prefabricated trusses, be prepared to give the truss
load in terms of total load and load per foot of span. Also know the
amount of overhang beyond plates if any and whether the truss ends
are to be cut square or cut plumb.
Spacing 10 12 14 16 18 20 22 24 26 28 30
4 ft 800* 960 1120 1280 1440 1600 1760 1920 2080 2240 2400
5 ft 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000
6 ft 1200 1440 1680 1920 2160 2400 2640 2880 3120 3360 3600
Table 1. Total truss load in pounds for common truss spacings and truss spans
*Total truss loads in pounds are calculated for 15 psf live load plus a 5 psf dead load for a corrugated steel roof.
Depending on the type of building, the distance from the floor to
the plate will vary. A 7-foot clearance under the plate (leaving an
8-foot ceiling at the top of the plate) is enough for poultry houses
and hog houses. Machinery storage buildings are usually constructed
with a 12-foot ceiling height. In some cases when large machines will
be stored, 14-foot ceiling heights are used. A minimum ceiling height
of 10 feet is recommended for dairy and beef barns. Use a ceiling
height of 16 feet to 20 feet for hay storage structures.
Poles must be at least 6 inches across at the top for all of the larger
and higher buildings. Ceiling heights of 8 or 10 feet need a top
diameter of only 5 inches.
SIZE OF BUILDING
There is a building width that works out best for each agricultural
use. Use a 40-foot-wide building for cattle sheds because it gives the
most usable area for the animals. You can make lean-to additions
to the 40-foot-wide building to increase the width up to 70 feet, but
be sure to allow for the reduction in eave height caused by the roof
slope of the lean-to addition. Machinery storage are commonly built
in either 30-foot or 40-foot widths. Because farm machines differ so
much in size, it is best to plan the building to fit the machines you
will store. The 36- and 40-foot widths are best for fruit storage
buildings. The use of clear span construction can increase the storage
area 5 to 10 percent over other types of construction. Side walls 12
to 14 feet high permit the use of mechanical handling equipment.
Florida Plan Service pole buildings and trusses are designed for
lumber with the strength of #2 Southern Pine. All lumber must be
properly cut and dried. Do not use lumber with large knots or other
defects, or that is warped and twisted. Some lists of material assume
that you will use dressed lumber.
The joints are usually the weakest points in farm building construc-
tion. Joints should be as strong as the wooden members. If you use
the wrong type or too few fasteners, you will reduce the strength
of the entire building.
Nails used in material treated with creosote hold less than when
used in untreated lumber because of the lubricating effect of the
preservative. Nails will also hold less when used in freshly treated
lumber that is not yet dry. Always use totally dry lumber. Nails with
a ring shank are recommended. Oil-hardened nails are stronger than
regular steel nails, so you can use a thinner shank to reduce the
chance of splitting. Oil-hardened nails cost more per pound, but there
are more nails in a pound, so the cost per nail is about the same. If
oil-hardened nails are not available, use hot-dipped, galvanized com-
mon nails for longer life and better holding strength than regular
nails will provide.
At least two 16d nails should be used to fasten 2- by 4-inch purlins,
braces and truss members. Use 12d nails when connecting 1-by-4
members. When nailing plates to poles, larger nails such as 30d or
40d are sometimes used. Plate-to-pole connections are best made with
Use machine bolts at least 2 inch in diameter with a 2-inch steel
washer on both ends. When fastening rafter supports, keep the head
of the bolt to the outside so it will not interfere with the siding. Bolt
connections are recommended for fastening plates to poles. Notch
the pole and use a 16-inch tree surgeon bit to drill through the plates
Split-ring connectors provide top-strength construction. One split-
ring connector with a /2-inch bolt is as strong as six /2-inch bolts
or 30 16d common nails.
The use of the correct fasteners is important at all points in any
structure. Truss-to-plate connections are the most critical in a pole-
type building. The roof must resist forces from the windward side
as well as uplift from the leeward side. Metal strapping or plate con-
nectors greatly improve uplift resistance and should be used in the
fabrication of all pole-type buildings constructed in Florida. Both
ends of every truss should be clipped. Purlin joints may also be
strengthened with hurricane clips.
CONCRETE PAD FOOTINGS
Concrete pads 18 to 24 inches in diameter and 12 inches thick are
usually used to carry pole loads. Clean the bottom of the hole of all
loose soil and make it flat, not ball shaped. Use a concrete mixture
of 1 part cement to 5 parts gravel and 6 gallons of water per sack
of cement. Pour the concrete in the hole at least 12 hours before set-
ting the poles. Use about 1 cubic foot of concrete for a hole of the
size mentioned above.
Dip or pump out all water in holes before pouring the concrete.
Consider relocating the building if water seeps into the bottom of
the holes while they are being dug.
Choose poles that have been commercially pressure treated with
a permanent preservative in accordance with Federal Specifications
TTW 571. Ask for poles that are branded on the side. The brands
identify the amount and quality of treatment. Poles marked or tagged
on the ends are not properly branded. You will lose the mark when
one end of a pole is put in the ground and the other is cut off when
the building is erected.
The pressure treatment process forces preservative chemicals into
the wood. This treatment gives the wood excellent resistance to ter-
mite attack and to decay. Cleanliness, paintability, color and odor
are factors to consider when choosing a preservative treatment.
Creosote is very effective against decay caused by fungi and
against termite damage. Creosote-treated wood cannot be painted
and has a pungent odor. Contact with creosote-treated wood can
cause skin irritation to humans and animals.
Pentachlorophenol, commonly called Penta, is an oil-borne preserv-
ative that is highly toxic to fungi and termites. Penta dissolved in
heavy petroleum oil is the most effective for preservation, but is not
paintable. Penta dissolved in light petroleum solvents is fairly clean
and paintable. Penta dissolved in liquid petroleum gas is very clean
and paintable. However, carcinogenic compounds called dioxins are
present in Penta-based preservatives, so the use of Penta around
humans or livestock should be avoided.
Water-borne salt preservatives are inorganic salts of arsenic,
chromium, copper or zinc. These preservatives work well where clean,
odorless and paintable surfaces are necessary. Some of these salts
remain water soluble after treatment and should not be used to treat
wood in contact with wet soil.
Caution should be used when handling preservatives or treated
wood. Creosote can cause a skin burn, especially in hot weather.
Treated wood should not be used where there is danger of con-
taminating food or animal feed. Creosote or penta should not be used
in greenhouses because their toxic fumes can seriously injure plants.
Water-borne copper salt preservatives are best for greenhouse appli-
cations. On-site preservative treatment is possible but not recom-
mended because it is difficult to get enough preservative penetration
to stop decay.
Proper embedment of poles is necessary to resist uplift and racking
forces from winds. Pole buildings are light and do not have a heavy
foundation, so it is important to protect the building from wind
damage by anchoring the base of each pole. This can be done by run-
ning a rod through the pole a few inches above the bottom of the
pole and then pouring a concrete collar at least 12 inches in diameter
around the base of the pole. Another method is to drive eight to six-
teen 20d nails half their length into the base of the pole before pouring
the concrete collar.
Poles should generally be embedded to a depth of one-fourth to
one-fifth of their height. All poles should be embedded to a minimum
depth of four feet. Vertical and horizontal loads, the bearing strength
of the soil and the pole size and spacing affect the proper depth of
embedment. Table 3 gives recommendations for embedment depths
based on building height and width and pole spacing for soils with
an average bearing strength of 2500 psf and for soils with a poor
bearing of 1500 psf. Soft clays, poorly compacted sands and soil on
which water stands during the wet season will have a poor bearing
strength. The recommendations given in Table 3 are based on 6-inch
diameter poles. Poles of other diameters will require different embed-
ment depths. A 4:12 roof slope and a 15 psf live load based on an
85 mph wind speed are assumed.
Spacing (ft) Width (ft)
Table 3. Recommended pole embedment depths
2500 psf Soil 1500 psf Soil
Bearing Capacity Bearing Capacity
Poles can be embedded by backfilling with soil from the construc-
tion site. Tamp moist soil in 8-inch layers into the hole. Initially back-
fill only one-third the pole depth until the trusses are ready to be
set. Concrete embedment of poles is not recommended in Florida.
The slight separation between wood and concrete that develops with
time allows the entry of moisture, which decreases pole life.
Roof trusses allow the economical use of clear spans from 20 to
60 feet wide. Wood roof trusses for single spans exceeding 60 feet,
however, need special design and are costly and difficult to ship and
handle. Simple wood rafters are economical for spans up to 20 feet.
Truss styles vary with span and design load.
Roofing sheets shed rain best when roof slopes are 3 in 12 or
greater. For worker safety and economy, slopes should be limited
to 6 in 12. Roof trusses are commonly spaced 2 to 4 feet apart,
although with properly designed trusses, spacing may be increased
to 8 feet or more. Spaces wider than 8 feet require stronger trusses,
plates and purlins, so professional design is recommended.
Trusses may be fabricated using nailed gusset plates, glued and
nailed gusset plates, bolts, split-ring connectors or metal-plate con-
nectors to connect truss members. Roof trusses can be built on the
job site, but quality control is difficult, especially if glue is used.
Trusses manufactured in a shop under controlled conditions are
available in most areas. Experience has shown that the most
economical pole building utilizes prefabricated trusses.
Trusses should be handled with care once fabricated or delivered
to the site. Always handle and store them in a vertical position to
avoid warping and overstressing. Although small trusses can be
handled by hand, it is recommended that a crane be used to handle
and set the trusses. Using a front end loader on a tractor is
Space 2-by-4 purlins laid flat for metal roofing 24 inches on center
for truss spacings up to six feet. Trusses spaced closer than 3 feet
can use 1-by-4 purlins laid flat on 24-inch centers. Plan to have a
purlin where the ends of two sheets butt together. This provides a
nailing surface under the end lap. Steel roofing should be 24- to
29-guage, 21/2-inch corrugated, or V-crimped galvanized steel. When
sheets are delivered, stack them on end so that water will not collect
in the corrugations.
If aluminum roofing is desired, use 21/2-inch corrugated sheets,
0.024 inches thick. Aluminum sheets normally come in 26-inch widths
which cover 24 inches on the roof with a 1 /2-inch corrugation lap.
You can get 48-inch wide sheets in some areas. Lengths of 6 feet to
12 feet are available. Each material supplier does not carry the com-
plete range of sizes, so check before you start to build to see what
lengths are stocked.
When laying the roofing, provide an 8-inch end lap and a 2-inch
corrugation side lap. There is a right side up for the sheets to make
this side lap possible. Use ring-shank galvanized nails with a lead
head or neoprene washer. Put one nail on every other corrugation.
Use aluminum nails with aluminum roofing.
Asphalt or wood shingles can be used for roofing material. This
type of construction is not recommended for pole-type construction
because of the expense of the shingles and the underlying decking.
If shingles must be used on a pole building, consult an engineer for
Bracing strengthens and adds rigidity to the building. Temporary
braces hold the frame in place during erection. Permanent bracing
is required to provide adequate strength to most buildings.
Pole-to-plate braces attached at a 45 angle allow the plate to carry
a larger load and tie the plate down in heavy winds. Generally pole-
to-plate bracing is not required when poles are spaced less than 8
feet apart. A properly braced plate with braces fastened at points
at each third of the plate's length can carry 80 percent more load
than a plate without braces.
Lateral knee braces fasten the truss to the pole and stiffen the walls
laterally across the building width. Braces must be stiff enough not
to bow under the load. The bracing used depends on building size
and whether the building has interior walls, sheathing or other stif-
Diagonal Roof Bracing
Diagonal bracing, also called wind or "X" bracing, keeps trusses
vertical and prevents the trusses from buckling from wind loadings.
Bracing should be installed at each end of the building and at 50-foot
intervals throughout the building's length. Diagonal bracing must
be installed during the setting of trusses as a safety procedure.
Bottom Cord Bracing
Bottom cord bracing, also called horizontal bracing or rat run, con-
sists of horizontal braces running parallel to the ridge of the building
and connecting the bottom cords of the trusses. It prevents buckling
of the bottom truss cord. Install 2-by-4's continuously the entire
length of the building unless a rigid ceiling is installed.
Install bracing as the trusses are being installed. Strong winds can
arise with little warning and damage unbraced or poorly fastened
Laying Out the Building
1. Locate and set corner stake A. Drive a nail in the top of the
stake to locate the exact corner (see Fig. 2).
Figure 2. Laying out building
2. Stake out a base line to establish the building orientation.
Measure the length of the building with a steel tape along this
3. Set the second corner stake B with a nail in the top at a distance
equal to the desired building length from A.
4. Measure back exactly 30 feet along line BA, set a stake, drive
a nail in the top, and hook one steel tape to the nail.
5. Hook a second steel tape on the nail at stake B, cross the tapes
at 40 and 50 feet, and establish line BC. Locate the third cor-
ner stake C on line BC at the desired width of the building. (A
right angle is formed when the sides of a triangle are in the ratio
6. From corner stake A, measure the width of the building. From
corner stake C, measure the length of the building; and set the
fourth corner stake D.
7. Recheck all four sides for the correct length, then check the
diagonals. The distance from A to C must equal the distance
from B to D, and the diagonals should cross each other at the
middle (see Fig. 3). Adjust the location of the stakes until the
diagonals and the sides are all equal.
Figure 3. Check for equal-length diagonals
8. Place batter boards at all four corners. Locate batter boards
far enough away from the corner stakes to operate hole-digging
equipment. This distance should be from 5 to 10 feet. The tops
SBased on the steps recommended by J. S. Boyd et. al. in Reference 1.
of all four sets of batter boards should be level and at the same
elevation. Batter boards should remain undisturbed until con-
struction is complete.
9. Stretch a chalk line from the batter board at D to the batter
board at A exactly over the nails in stakes D and A. Put a nail
on each batter board to locate permanent reference points.
Repeat this procedure for the other three sides.
10. Determine the four corner-pole locations (see Fig. 4).
Figure 4. Locating poles
11. Locate the center of the corner pole by measuring in from the
chalk line one-half the diameter of the pole plus 1 z inches for
12. Hook a steel tape over the nail at D and measure along chalk
line DC the distance to the first pole. Locate the pole center
one-half the pole diameter in from the chalk line, plus 1/2 inches
for the girts.
13. Leave the tape hooked to the nail at A and measure to the
second pole. Repeat for all poles.
14. Take down the chalk line, and remove the corner stakes.
15. Drill holes 12 inches deeper than the set of the pole and 18 to
24 inches in diameter (see Fig. 5 and Table 3).
Figure 5. Typical embedment details
16. Pour a 12-inch-thick layer of concrete into the bottom of each
hole. (An 18-inch-diameter hole takes about 1 cubic foot of
17. Do not place concrete in water-filled holes. Pump or bail the
water out of the holes first.
18. Allow the concrete to set for at least 12 hours before placing
poles in the holes. Do not place the poles on top of fresh con-
crete. If necessary to resist uplift, concrete collars should be
installed at this time.
19. Reset the chalk lines.
.. L., I
20. Select four straight poles for the corners (see Fig. 6).
Figure 6. Pole setting
21. Set the poles in the corner holes 1 / inches from the chalk line.
At the same time, plumb the hole on the two outside edges by
placing a straight board with a carpenter's level on the outside
edge of the pole.
22. Fill and tamp the poles to one-third their depth.
23. Temporarily brace the corner poles from two directions by put-
ting braces on the outside of the building. Put the top of the
braces below the bottom of the brace plate location.
24. Place the rest of the poles in the holes with the straightest side
outward. Bumps and curves on the inside will not alter the
shape of the building.
25. Set each pole plumb with its edge 1 / inches from the chalk line.
Be sure the pole spacing is correct.
26. Check that the side poles are in line by sighting from corner
pole to corner pole.
27. Brace the side poles from the inside.
Determining Plate Levels
28. Find a level point on each pole. Use an engineer's level for this.
If you don't have an engineer's level, use a water-filled
transparent hose to find the level points (see Fig. 7).
Figure 7. Establishing plate level points
29. Drive a nail half-way into the poles to mark the level points on
30. Check the level points on all poles with a taut chalk line from
corner pole to corner pole. Be sure the chalk line is taut and
that the wind is not blowing it out of line.
31. Measure up from the level points to establish the plate lines.
Putting Up Plates
32. Determine the required distance from the level points on poles
to the bottom of plates from the plan. Cut a 2-by-4 to this dimen-
sion to use as a measuring stick. Use it to measure the exact
plate heights (see Fig. 8).
33. Cut the plates squarely and to the exact length.
34. The length of plate A is equal to the distance from the center
line of pole 2 to the outside of pole 1, plus the thickness of a
2-inch girt (11/2 inches).
35. The length of plate C is equal to the distance from the center
line of pole 2 to the center line of pole 3.
36. The length of plate B is equal to the length of plate A minus
the thickness of a 2-inch girt or a 2-inch plate (1'/ inches).
PL ATL C
Figure 8. Putting up plates
37. The length of plate A equals the length of plate C.
Start one ring-shank nail in the center of the plate 1 V2 inches
from the end (except for the corner ends of plates A and B).
Set the plate on the 2-by-4 measuring stick held against the pole,
and rest the measuring stick on the nail driven near the bottom
of the poles. Center the end of the plate on the pole and drive
a nail into the pole. Drive the nail into the other end of the plate.
Put up the inside plate, with its top level with the top of the
outside plate. Continue installing plates on one side of the
Check the plan for the correct number of nails and bolts to
connect the plates and proceed to attach all plates to poles. If
bolts are needed, use a 16-inch tree surgeon bit for drilling
through plates and poles. The preferred method of attaching
plates to poles is with bolted connections. Repeat this process
for plates on the opposite side of the building.
Use a saw to cut off pole tops 4 to 6 inches above the top
edge of the plate. This is a dangerous operation. Make certain
you have good footing and are using a safe saw in good
operating condition. The vertical bridging will attach to the
remaining stub. Stretch a chalk line between the corner posts
to make sure all pole tops are cut at the same level.
PL ATE A
Setting Intermediate Poles
38. If the plan calls for short poles between framing poles, set them
in the holes about 2 feet deep. Intermediate poles are used to
provide support for the girts when the framing poles are more
than 8 feet apart. Make sure that the outer edges of any short
poles are 1V2 inches from the chalk line (see Fig. 9).
Figure 9. Setting intermediate poles
39. Check pole alignment by sighting along the outside of the fram-
ing poles, or use chalk line stretched along the outside of the
40. Backfill to one-third of the hole depth and tamp all intermediate
41. Apply girts by using (A) butt joints or (B) lap joints, depending
on the length of the girt (see Fig. 10).
Figure 10. Girt installation
42. You can use both butt and lap joints on the same building.
Using both may save some time when putting on the girts.
43. Use two 16d ring-shank nails in each end of the girt.
Putting Up Trusses
44. Fill all holes and tamp. Install the first piece of vertical bridging
before the truss is set on the plate (see Fig. 11).
45. Check to make sure that each truss is the correct length. Start
placing trusses, working from one end of the building to the
other. If available, use a crane to place trusses. If the trusses
must be placed by hand, start with the truss upside down, and
place one end over one plate. Then set the opposite end of the
truss over the other plate.
46. The truss is now supported upside down over the plates. Pivot
the truss into an upright position and hold it steady. The first
truss to be erected can be braced with temporary 2-by-4 braces
to the ground and plates. As additional trusses are placed, they
can then be held steady with a board extending from the last
truss placed. Nail the truss heel to the vertical bridging. Before
nailing, be sure that the truss is in the correct position on the
plate, and that the width between the outside edges of the plates
is the width called for on the plan. Install diagonal bracing and
bottom cord bracing.
Figure 11. Putting up trusses
47. Install the second piece of vertical bridging on each pole after
all trusses are nailed or bolted in place.
48. Sight along the plates on the front of the building to be sure
that they are straight.
49. The plate on the back side of the building may be slightly out
of line. If this is the case, the plate can be left as it is or the
difference can be split between the two sides.
50. Install bracing and attach hurricane clips or strip anchors to
the trusses (see Fig. 12).
Figure 12. Truss and plate bracing
Laying Out Roofing
51. Measure the distance from the ridge to the eave along the rafter
and add 2 inches for metal overhang. This is the length to use
when figuring the required length of the roofing sheets (see Fig.
Figure 13. Laying out roofing
52. Choose roofing sheet lengths that overlap at least 8 inches at
each joint. Consult your dealer to determine what lengths are
53. You can sometimes get the right overlap by using a different
width ridge roll, which allows the top sheet to start farther down
from the ridge. Extend the lower sheet 2 inches below the first
54. Measure the distance along the ridge from the outer edge of
the end rafters and add 1 foot (6 inches on each end) for finishing
(see Fig. 14).
55. Most sheets cover a 2-foot width. Divide the total distance (from
step 54) by 2 feet to find the number of rows you need. Roofing
is sold by the square (10 feet by 10 feet), or by 100 square feet.
A square will not cover 100 square feet, because it does not allow
for overlaps. If you use sheets other than 2 feet wide, consult
your roofing material supplier about coverages.
Figure 14. Ridge length
56. Measure the plate-to-eave distance of the end rafters on one side
of the building (see Fig. 15.).
Figure 15. Installing purlins
57. If the distance varies, mark a point (measuring from the ridge
down) that is equal to the shortest distance measured.
58. Place a taut chalk line between these two points on the rafters.
Figure 16. Applying first roofing sheet
Figure 17. Finish applying roofing
59. If the plate-to-eave distances of the intermediate rafters vary
less than 1 inch, you can correct the differences when putting
in the first eave purlin. (Let the purlin overhang the short
rafters.) If there is a difference of more than 1 inch, reset the
chalk line to the length of the shortest rafter and cut the others
off to match.
60. Choose a straight 2-by-4 for the first eavee) purlin. Use the taut
chalk line or corrected rafter overhang as a guide. Use butt
joints on the first purlin.
61. Measure up from the eave along the end rafters. Measure a
distance the length of the first sheet, less the 2-inch metal over-
hang, and half the end lap. Mark this point.
62. Again, place a taut chalk line between these two new points
on the end rafters.
63. Place 2-by-4 purlins laid flat above and below this chalk line
using a lap joint. Nail each 2-by-4 purlin with two 16d ring-
64. Locate the other purlins, spacing them 24 to 30 inches on center
between the purlins already placed.
Putting On Roofing
65. Start putting the roofing on the east end of an east-west
building, or at the north end of a north-south building. The side
laps then will be away from the prevailing winds.
66. Make a line on the purlin at the eave, parallel to the edge of
the purlin. With a 6' by 8' by 10' triangle, make a line at right
angles to the eave to use as a guide for placing the first sheet
of roofing. If this line is not parallel to the first rafter, you might
be able to rack the roof until it is. If not, let the metal overhang
vary at the end of the building (see Fig. 16).
67. Continue putting up the lower row of sheets, lapping 1V2 cor-
rugations and nailing with ring-shank nails with lead heads and
neoprene seals (see Fig. 17). Follow the roofing manufacturer's
nailing recommendations when applying roofing material.
68. Put on the other rows of roofing, starting at the same end of
69. Install the siding on the ends and butt it up to the roofing on
the gable ends.
70. Nail the 2-by-8 trim board over the siding to the ends of the
purlins. Then bend the metal overhang over the 2- by 8-inch
trim and nail with galvanized roofing nails.
- -RIDGE ROLL
TOP OF PLATE
SCALE 3/16 =1-0
6" DIA. TOP) POST
COMPACTED EARTH FLOOR
CROWNED 6" AT CENTER "
L SLOPING TO OUTSIDE I
POLESf 8'-00 O.C. 40'-0" O.A.
SCALE: S/e Il'-0
SCALE- 36= -C
PRE-FAB WOOD TRUSSES
S DOUBLE PLATE, SEE DETAIL
4'-f 4-. 4-0 .4-0. .- 4'-0 4-0" 4-0"4-" 4-0
II TRUSSES at 4'-0" O.C 40'-0Q O.A.
ROOF FRAMING PLAN
SCALE 3/6." I.-0
-PRE-FAB WOOD TRUSS, SPACING AS PER PLAN
_________. I *.ALINS at 24" O.C. MAX.
=2 HURRICANE CLIPS EA TRUSS
2 1/2" BOLTS W/ NUTS & WASHERS
DOUBLE 2"x 12" PLATE, NOTCH POLE 2"
6" DIAMETER (TOP) POLE
PLATE CONNECTION DETAIL
SCALE 1-i ="= I 'O
-PRE-FAB WOOD TRUSS, SPACING AS PER PLAN 6"DIA
- -- RLINS at 24 OC MAX. REQUl
2 HURRICANE CLIPS EA TRUSS I i
L- D 2" BOLTS W/ NUTS 8 WASHERS ANNCH
H2"x 12 PLATE EA SIDE OF POLE. CONCR
NOTCH EA SIDE OF POLE I ---
INSTALL SPACERS BETWEEN POLES.
6" DIAMETER (TOP) POLE
UNDISTURBEDT I'-" ONCR
ALTERNATE PLATE CONNECTION DETAIL POLE EMBEDMENT DETAIL
SCALE 1-1 0" SCALE 1/2 =1'-
--I. ALL FASTENERS USED SHALL BE HOT DIP
2. SELF-SEALING ROOFING NAILS SHALL BE
USED TO ATTACH GALVANIZED METAL ROOFING
3. ALL LUMBER USED SHALL BE NEW, PRESSURE
TREATED, UNLESS OTHERWISE SPECIFIED
4. SIDING USED SHALL BE EXTERIOR GRADE.
5 ALL EXTERIOR EXPOSED LUMBER (TO INCLUDE
SIDING AND TRUSSES) WHICH HAVE EITHER
BEEN CUT OR WERE NOT PRESSURE TREATED
SHALL BE PAINTED.
6. POLES SHALL BE A MINIMUM OF 4' IN
7. USE 10 OR 12d NAILS TO FASTEN TOGETHER
:CTIVE 2" THICK MATERIALS.
8 USE HURRICANE CLIPS AND 4d NAILS TO
FASTEN PURLINS TO TRUSSES.
Installing Siding and Finishing
71. Remove the temporary pole and truss bracing.
72. Install the end wall girts.
73. Install windows, siding and doors as desired.
74. Install trim, gutters, down spouts and other accessories. Pro-
vide down spouts at both ends of buildings more than 40 feet
75. Install utilities as needed.
76. Clean and landscape the area.
Detailed plans for pole buildings to satisfy many agricultural needs
are available from the Florida Plan Service, 101 Frazier Rogers Hall,
University of Florida, Gainesville, Florida 32611. Figures 18A and
18B show a plan for a typical clear span pole building.
1. Boyd, J. S., B. F. Cargill, R. L. Maddex, and M. L. Esmay. 1971.
How To Erect a Pole-Type Clear-Span Building. Extension
Bulletin E607. Michigan State University, East Lansing,
2. Irish, W. W., G. R. Bodman, C. W. Mellor, G. D. Wells, R. A.
Parsons. 1977. Pole and Post Building Construction. Northeast
Regional Agricultural Enginering Service, Ithaca, New York.
3. Lytle, R. J. 1978. Farm Builders Handbook. Structures Publishing
Co., Farmington, Michigan.
4. Midwest Plans Service. 1983. Structures and Environment Hand-
book. MWPS-1. Midwest Plans Service, Ames, Iowa.
5. Patterson, D. 1969. Pole Building Design. American Wood
Pressures Institute, McLean, Virginia.
6. Phillips, R. E. 1981. Farm Buildings, From Planning to Comple-
tion. Doane Western, Inc., St. Louis, Missouri.
1262 07217 2363
3 126 072 236
This publication was promulgated at a cost of $1536.39 or 85.4 cents
per copy, to provide useful information on Pole Type Construction.
COOPERATIVE EXTENSION SERVICE, UNIVERSITY OF FLORI-
DA, INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES, K. R.
Tefertller, director, In cooperation with the United States Department F
of Agriculture, publishes this Information to further the purpose of the
May 8 and June 30, 1914 Acts of Congress; and Is authorized to pro-
vide research, educational Information and other services only to indi-
viduals and Institutions that function without regard to race, color, sex or national ori-
gin. Single copies of Extension publications (excluding 4-H and Youth publications) are
available free to Florida residents from County Extension Offices. Information on bulk
rates or copies fdr out-of-state purchasers Is available from C. M. Hinton, Publications
Distribution Center, IFAS Building 664, University of Florida, Galnesville, Florida
32611. Before publicizing this publication, editors-should contact this address to deter-
~- ~~-y r, 'I '. TF~;Tf~