Building & Zoning Department
215 S. Broadway, Louisburg, KS 66053
913-837-5811 · louisburgkansas.gov
rwhitham@louisburgkansas.gov
DECKS
Permit Fee:
$75 if greater than 30 inches off the ground.
Otherwise, $25.
Items Required for Permit:
Application.
Site Plan showing Lot, House and Deck.
Deck Plans
Requirements:
36” deep footings.
Construction per 2003 IRC Deck Guide (available in office).
Must meet building setback requirement (25 foot rear yard).
Excavator’s License required if digging for hire with mechanical equipment.
Contractors should be licensed through Miami County, Kansas, Contractor Licensing Code.
Verify with HOA, if applicable, additional accessory building requirements.
Deck or porch constructed in the front yard shall meet front yard setback and build line
requirements. A survey may be required.
Inspections:
Pier Holes.
Final.
Deck Hangers (Joists).
Building & Zoning Department
215 S. Broadway, Louisburg, KS 66053
913-837-5811 · louisburgkansas.gov
rwhitham@louisburgkansas.gov
APPLICATION FOR OTHER STRUCTURES
Date: _____________ Permit # ______________________________
Property Owner: ____________________________________________________________________________________
Property Owner Address: _________________________________________ Phone: _____________________________
Contractor: (Must be Licensed in Miami County)
Contractor Name: ___________________________________________________________________________________
Contractor Phone: ______________________________ Email: _______________________________________________
General: _________________________________________ Mechanical: _______________________________________
Electrical: ________________________________________ Plumbing: _________________________________________
Foundation: ______________________________________ Site Utility: ________________________________________
Roofing: _________________________________________ Fire Sprinkler: ______________________________________
Description of structure to be constructed: _______________________________________________________________
Estimated cost of new construction: _____________________________________________________________________
Size of structure: Width ____________ Length ____________ Total square footage ____________
Intended use of structure: _____________________________________________________________________________
Principal material to be used in construction: _____________________________________________________________
I, ______________________, hereby certify that the information provided herein is true and correct and that all Zoning
Regulations shall be complied with. I certify that all contractors listed above are licensed under the Miami County,
Kansas, Contractor Licensing Code. I further understand that any permit based upon false or incorrect statements of a
material fact necessary to the issuance of the permit, shall be void.
Date: _____________ Signature: __________________________________________________
Office Use Only
ATTACHED:
_____________ Site Plan _____________ Building Plans _____________ Date Paid
_____________ Amount Due _____________ Receipt #
Assigned address: ___________________________________________________________________________________
click to sign
signature
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Permit and Construction Guidelines
under the 2003 IRC
Residential Decks
Produced by TimberTek Consulting
Johnson County Building Officials Association
This publication is endorsed by:
Johnson County Contractor Licensing Program
Published by:
USES AND LIMITATIONS OF THIS DOCUMENT
The purpose of this document is to provide the public, contractors, homeowners and city officials
with deck construction guidelines that will be accepted by the majority of jurisdictions within the
Johnson County and Kansas City metropolitan area. Members of the Johnson County Building
Officials have agreed that the guidelines contained in this document provide construction
principles and practices that if followed will satisfy the general permit and construction
requirements in their jurisdictions. The guidelines are based on the 2003 International
Residential Code.
This guideline does not contain all of the local jurisdiction requirements for obtaining permits,
fees, or procedures for inspection. The guideline also does not prevent the local jurisdiction
from asking for additional information or varying from specific requirements based on locally
adopted code and ordinance requirements. Other deck design approaches and construction
methods may be approved by the local jurisdiction. Prior to beginning any new construction,
additions or maintenance work on decks, consult with your local jurisdiction to verify that use of
this guideline is acceptable and to familiarize yourself with their specific permit application, plan
review and inspection procedures.
This guideline is limited to deck designs using a uniform floor loading of 40 pounds per square
foot live load and 10 pounds per square foot dead load over the entire floor of the deck. Decks
supporting loads in excess of the standard uniform loads will require specific approval from the
local jurisdiction and may require design by licensed architects or engineers. Decks supporting
roofs, hot tubs, spas, sun rooms, etc., and decks with cantilevers exceeding 3 feet are examples of
deck design elements that are not covered by this guideline and will require additional direction
from the local jurisdiction.
Where deck ledgers are attached to the dwelling the assumed attachment is over hardboard siding
with connection through to the rim joist of the house. Where the exterior consists of other siding
materials (stucco, shingles, asbestos siding, etc.) or attachment of the ledger is to brick, concrete,
stone or other materials consult with your local jurisdiction for acceptable attachment methods.
This is a living document and is subject to change from time to time as codes or other
requirements change.
First Edition
October 2003
Residential Decks
Permit and Construction Guidelines
Builders and homeowners are required to obtain a permit
prior to constructing, altering or replacing a deck.
Plan Submittals
The following information shall be submitted to the building department for their review in order
to obtain a deck permit. All of the information shown on the sample documents should be
contained in all plan submittals. Additional information may be necessary. Plan review fees and
permit fees will vary from one jurisdiction to another.
The first requirement is submittal of a Site Plan, drawn to scale, for the property where the deck
is to be built. Please provide all the information shown on the sample.
D
D
D
B
L
Street name and address
D = Distance to
property lines
Site Plan
D
i
m
e
n
s
i
o
n
o
f
l
o
t
Dimension of lot
Show house on lot
Show deck location
with respect to house
and lot lines
House
Deck
On angled property lines,
the dimension “D is
measured perpendicular
from the property line to
the nearest point of the
structure
5’ Easement
Dont forget to
show easements
and building
lines on your site
plan
Dimension of lot
Dimension of lot
Back of curb
Right-of-way
Front property line
Figure 1
All lot dimensions shall be shown on the Site Plan. The distances to property lines must meet
any side and rear yard setback requirements. This Site Plan may be drawn by the builder or the
homeowner and does not have to be sealed by a design professional.
1
The second requirement in obtaining a permit is the submittal of a Deck Plan drawn to scale.
This plan should contain as much information as possible about the deck and its construction.
The information shown on the sample Deck Plan is the minimal requirement for the plan review
process. Additional information may be required by the building department in order to
complete their review. This plan may also be drawn by the builder or the homeowner and does
not require the seal of a design professional. Some designs and construction methods may,
however, require the use of an architect, engineer or other design professional.
14’
12’6”
16’
Deck Plan
10’
4’
2x6 Cedar decking over #2 SP
Treated 2x10’s @ 16” o.c.
6’ 6’ 4’
5’7”5’7”5’4”
2 – #2 SP Treated 2x10’s
6x6 Cedar Posts – 9’ top
of pier to bottom of
deck, with 36” railing
Ledger attached with
1/2” corrosion resistant
lags @ 12” o.c.
3’
All piers to be 14 dia.
and 36” deep Posts
attached with Simpson
AB66R Post Base or
equivalent
6’
HOUSE
Figure 2
The specific construction information shown on the sample Deck Plan can be found in the tables
and diagrams that are provided with this document. Refer to the tables for specific requirements
for designing joists, beams, posts, deck
piers and connecting the deck to the
house. The stair stringers must also be
cut and connected properly and must
not exceed the spans specified for
safety reasons. The information
contained in this document should not
be considered a complete list of code
requirements.
2’-0”SP #2 ACQ5/4x6
1’-4”Cedar #25/4x6
1’-4”Trex5/4x6
2’-0”Cedar #22x6
2’-6”SP #2 ACQ2x6
Max. spanSpecies/gradeMember
Decking – 300# Concentrated Load
Spans for decking material
A variety of decking materials may be
used for the flooring and railings.
Please specify the size and type of material
Table 1
2
and the framing direction, such as ‘5/4 Radius Edge Cedar Decking running at a 45 degree angle
to the floor joists.’ This is important because certain products like Radius Edge Decking have
limited span capabilities as shown in Table 1.
The deck must be constructed of either a naturally decay-resistant lumber or a pressure-treated
lumber (ACQ) and be designed to support a live load of 40 psf. All overhead power lines must
be located at least 10 feet above the deck floor or be at least 3 feet horizontally away from the
floor surface. An exterior light for the deck and lighting on the stairs is required.
Columns and Piers
The size of the wood columns and concrete piers that are required to support a deck is based on
the square footage of deck being supported by that column and pier. This square footage can be
determined by using Figure 3 as an example. A column and pier supports an area of deck that is
half way to the next support in any direction. The house is considered a support. In Figure 3
below, the interior post supports half the joist span going back to the house and half the joist
span going toward the outside edge of the deck. Since each set of joists span 8 feet, the post and
pier supports 4 feet of the span in each direction. That means the interior post and pier are
carrying a total of 8 feet parallel to the joists.
20’0”
16’0”
BD
CC
Post Row 1
Post Row 2
House Wall
Tributar
y
load area for posts
Tributary
load area on
perimeter
post
Tributary load area
on corner post
Tributary load area
on perimeter post
Tributary load area
on interior post
Joists (typ.)
Beams (typ.)
B = Beam span
C = Joist span
10’
Figure 3
We then determine the distance between posts and piers parallel to the beam. Since the posts are
set 10 feet apart in this diagram, the interior post and pier supports 5 feet in both directions for a
total of 10 feet along the length of the beam. These two dimensions then give us an area of
3
80 square feet of deck supported by the interior post. The perimeter posts carry half the area the
interior post carries, or 40 square feet, and the corner posts carry half the area of the perimeter
posts, or 20 square feet. Now the size of the columns and the piers can be determined using
Tables 2 and 3.
Table 2 on the right shows the size
of post that is required to support a
specified area of deck and the
height that post may be. The
maximum post height is measured
from the top of the concrete pier to
the bottom of the beam the post
supports. This same post may
continue on up to provide support
for the guardrail around the deck,
but that additional length is not
counted as part of the maximum
post height.
13’14’14’15’15’16’17’17’1717’17’17’17’17’
6x6
(No. 1)
16’
16’17’17’17’17’17’17’1717’17’17’17’17’
6x6
(No. 1)
7’
4’
16’
8’
6’
144
7’
15’
8’
6’
156
6’
14’
8’
6’
168
6’
13’
7’
6’
180
5’
13’
7’
5’
192
7’13’16’17’17’17’17’17’
6x6
(No. 2)
7’8’8’9’10’11’12’13’14’4x6
5’6’6’7’7’8’9’10’10’4x4
Redwood
Western Red Cedar
16’17’17’17’17’17’17’1717’
6x6
(No. 2)
9’
7’
132
9’
7’
120
10’
8’
108
12’
9’
72
11’
9’
84
10’
8’
96
13’14’14’4x6
10’10’10’4x4
Southern pine
604836
Tributary load area to post (ft
2
)
Post
size
Species
Maximum post heights for 40 lb/ft
2
deck design
40 lb/ft
2
live load – 10 lb/ft
2
dead load
Table 2
To use the table, simply find the square footage of deck being supported by the post, and match it
with the species and size of the post to find the maximum height of that particular column.
A critical part of the deck construction is
the concrete pier that supports each post.
If they are too small the deck could settle
over time and become uneven. To use
Table 3, select the square footage of deck
supported by the pier. This is the same
area that was just used for the post sitting
on the pier. Based on the square footage
being supported, select the diameter of the
pier required. Remember that all piers are
to be a minimum of 36 inches deep to go
below the frost line. At least 1-inch of the
pier should be elevated above grade with
the top sloped for drainage.
Figure 4
36”
Sloped for drainage
Column anchor
Critical zone
for compaction
W
W = Pier diameter
W
Soil pressure cut
by 1/2 at this level
60°
Sawn end of post field
treated with water-
repellant preservative
Footing for use in
ground frost areas
Concrete Pier
Elevated a minimum of
1-inch above grade
Bottom of pier hole must not
contain any loose dirt
Pier sizes can be chosen individually, based on the square footage of deck supported by each
pier. That would mean each pier might require a different diameter hole. An easier way is to
determine the largest diameter hole required and make all the holes that size. This method will,
however, require more concrete. Which ever way it is done, this information must be shown on
the Deck Plan.
Once the post and pier sizes are determined, a connection must be made between the post and the
pier. This connection must resist lateral movement as well as uplift. That means a column
anchor must be used to attach the post to the pier. A ‘drift pin’ simply drilled into the bottom of
4
the post is not sufficient. The sample plan states a Simpson AB66R Post Base or equivalent is
being used to anchor the post to the pier. Be sure to specify some type of column anchor on the
plans. Column anchors are made to fit 4x4 or
6x6 posts. Some column anchors are designed
to be set directly in the concrete when it is
poured. Others can be drilled into the concrete
later so they can be placed exactly where they
need to go after the concrete has set up.
Ledger to House Connection
Decks are usually supported on one side by a
ledger attached to the house. This ledger
attachment is critical to insure the deck is safely
and securely supported at this point. When the
ledger is attached to the house, there are very
specific requirements that must be met. Follow
the diagrams closely for the proper attachment
of the ledger.
Table 3
8820”
10422”
12624”
4014”
5616”
7218”
3212”
2010”
148”
Square footage of deck
that can be supported
Pier diameter
Pier sizes based on deck area supported
Based on 2000 psf allowable soil bearing capacity
The deck ledger shall not
be nailed to the house. It must be lagged or bolted to the rim joist of
the house which in turn must be securely attached to the framing of the structure and sitting on
the foundation wall. Use Table 4 to determine the proper attachment of the deck ledger to the
rim joist of the house.
Two each joist
space with three
every other space
Two in each joist
space
Each joist space
with two every
other space
Each joist space
Two every third
joist space
Equivalent spacing
joists @ 16” o.c.
Two in each joist
space
Each joist space
with two every
other space
Each joist space
Two every third
joist space
Every other
joist space
Equivalent spacing
joists @ 16” o.c.
On-center spacing of lag screws (inches)
6” o.c.
13 – 18 ft
8” o.c.
15 – 18 ft
12” o.c.
7 – 8 ft
16” o.c.
8 – 10 ft
8” o.c.
9 – 12 ft
12” o.c.
11 – 14 ft
5 – 6 ft0 – 4 ft
16” o.c.24” o.c.
3/8” dia. Lag
24” o.c.32” o.c.
1/2” dia. Lag
6 – 7 ft0 – 5 ft
Joist span (feet)Lag size
Required size and spacing of corrosion resistant lag screws
for attaching deck ledger to house for a given joist span
Table 4
The size and spacing of the lag screws is based on their capacity. Lag screw values are assumed
to be 325 pounds for 1/2-inch lag screws and 190 pounds for 3/8-inch lag screws. The span of
the floor joists determines how much load is being transferred to the ledger and thus to the lag
screws. Use Table 4 by picking a lag screw size and then find the span of the floor joists.
5
Under the span will be the required on-center spacing of the lag screws. Since some lag screw
spacing will interfere with the framing layout, an equivalent spacing is also provided that may be
used in lieu of the specified on-center spacing when the joists are laid out at 16” o.c.
Pilot holes shall be drilled for lag screws 1/2 inch or larger. The clearance hole for the shank
shall have the same diameter as the shank. The lead hole for the threaded portion shall have a
diameter equal to 60% to 75% of the shank diameter. Pilot holes shall not be drilled for 3/8 inch
lag screws. All lags and nails used to connect framing members will be placed at least 2 inches
from the ends and edges of the lumber as shown in Figure 5.
The use of lag screws, along with all the other metal connectors used to build a deck, brings us to
a very important point. The use of proper fasteners and connections with treated lumber is
critical to the overall performance of the structure. Standard carbon-steel nails and fasteners will
rust and corrode with time, causing unsightly stains and possibly an eventual failure to hold
securely. Therefore, the lag screws supporting the ledger, and all other connectors used in
constructing a deck, must be hot dipped galvanized or stainless steel. G60 Electroplated
fasteners are not
recommended for use with treated lumber. Since treated wood will corrode
standard carbon-steel and aluminum, it is of extreme importance that all the connectors and
flashings used in deck construction be able to withstand direct contact with this material. The
new ACQ treatment that will replace CCA after December 31, 2003, is even more corrosive than
its predecessor. Therefore, it will be even more important to use hot dipped galvanized or
stainless steel connectors in lieu of standard carbon-steel fasteners. Check with your supplier to
be sure you are getting the proper corrosion resistance on all connecting hardware, such as joist
hangers and column anchors as well as lag screws, deck screws and nails.
Figure 5 describes the
equivalent spacing of lag
screws when joists are s
at 16” o.c. This equivale
spacing described in Table 4
may be used in lieu of the o
center spacing listed.
Many i
paced
nt
n-
ndividuals have
al
the
to
Figure 5
he attachment of the 1x4 is made using 3 – 16d hot dipped galvanized nails in a staggered
en
16” o.c.
Equivalent to 12” o.c. lag spacing
with joists spaced at 16 o.c.
Two lags required at each end
2 inches from ends and edges
Lags in each joist space
with two every other space,
2 inches from edges
12” o.c.
Deck ledger attachment to house
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
Lag screws shall penetrate the house rim
joist and extend at least 1/2” beyond.
This requires a minimum 5” lag screw.
House rim is adequately anchored
to house framing and is sitting on
foundation wall
1x4 treated spacer attached to house
rim with three 16d nails staggered
Deck ledger board
1x4 treated spacers
attached ledgers directly
against hardboard siding.
This will lead to the eventu
deterioration of the siding.
Therefore, a 1x4 treated
spacer shall be placed
between the siding and
ledger board to allow for
water drainage and for air
get to the siding so it
can stay dry.
T
pattern, nailed through the siding and into the rim joist of the house. The lag screws must th
go through the 1x4 and into the house rim joist. Note that this attachment requires the lag screw
6
to penetrate the house rim joist and extend at least 1/2" beyond. That means this connection
requires a minimum 5” galvanized lag screw with a standard galvanized washer.
Some builders or homeowners may want to remove the siding and attach the ledger directly to
f
d
.
e
Figure 6
In order to attach a deck to a
e
ck.
the
the rim joist of the house. This requires very close attention to flashing details so water cannot
get to the house rim and cause structural damage to it and possibly even the ends of the floor
joists. Figure 6 shows that proper flashing extends at least 6 inches up behind the siding and
housewrap. The flashing should then extend down past the ledger board and end with a drip-
edge at the bottom. To avoid deterioration, the flashing must be galvanized steel and not
aluminum. Holes drilled for the lag
screws should be caulked before the
ledger is applied to prevent water
from entering the main structure of
the house. Galvanized or stainless
steel washer spacers assure drying o
the 2x ledger.
The house rim joist must be securely
.
.
.
Flashing should extend at least 6”
up behind the siding and housewrap.
Flashing should extend down behind
the ledger board to a drip-edge.
2 – 4 galvanized or stainless steel
washers for spacers assures drying
of the 2x ledger.
Carefully caulk the bolt
holes after drilling to assure
that water does not enter the
main structure of the house.
Ledger flashing
anchored to the house framing and it
must be sitting on the foundation
wall. Ledgers shall not be attache
to cantilevers unless the connection
is engineered or the following
prescriptive method is followed
Note there are limitations imposed
on this prescriptive method. Be sur
to follow all the details very closely.
Attaching a Deck to a Cantilever
Figure 7
. .
. . .
Max. 2’ Cantilever
Simpson LS90 Gusset
Angles or equivalent,
nailed to both sides of
doubled joists or
doubled wood I-joists
with 12 – N10 nails
Doubled 2x10’s or
doubled I-joists at
16” o.c. with solid
blocking between
each joist over
foundation wall
Max. 16’ deck joist span
.
1/2” lag screws must
penetrate house rim
Attaching deck to cantilevered floor joists
Original joist nailed to
sill w/ 3 8d nails
Doubled joist nailed to sill
w/ 3 – 8d nails
Sill plate
. . .
1x4 treated spacer nailed to the
house rim w/3 – 16d nails
cantilevered portion of a
house, it is critical that the
rim joist be able to carry the
added load of the deck in
addition to the weight of th
exterior wall which is already
sitting on it. Since the rim
joist is only nailed into the
ends of the floor joists, that
connection is not sufficient to
support the extra load
imposed on it by the de
This is especially true with
wood-I joists which only
have two nails connecting
rim to each wood-I.
7
The first requirement for attaching a deck to a cantilever is the house joists must be 2x10’s or
on-
t
o
he maximum deck joist
16
Figure 8
e laid out at 16 inches on-center. Figures 7 and 8 show
oor
raming around a chimney
erior
mbers
cient
Figure 9
wood-I joists spaced at 16 inches on-center. Each 2x10 joist must then be doubled with an
additional 6 foot No. 3, Doug Fir, 2x10 nailed together with 10d common nails at 16 inches
center staggered. Wood-I joists must also be doubled with 30-inch long web stiffeners added.
The web stiffeners shall be nailed on with a row of 4 – 10d nails every 16 inches. The original
joists and the added joists will each be toe-nailed to the sill plate with 3 – 8d nails. Solid
blocking between the 2x10 joists or wood-I’s shall be provided over the foundation wall.
The next thing that must be
done is to attach the rim jois
to the doubled floor joists
with Simpson LS90 gusset
angles or their equivalent.
These angles are designed t
transfer the load imposed on
the rim by the deck back into
the doubled joists. Each of
these gusset angles shall be
nailed on with 12 – N10
nails, six nails into the rim
and the other six into the
doubled joists.
15’-
ld
Joists shall be reinforced
with a minimum 6’ long,
No. 3, Doug Fir 2x10’s,
nailed to the cantilevered
floor joists with 2 – 10d
nails at each end and at
16 o.c. top and bottom
staggered
5” Max. sill to beam
16’ Max. deck joist span
Two 1/2” lag screws at
16” o.c. for 16’ joist span
For I-joists,
provide 6 long
double joist with
30” long fillers
Attaching deck to cantilevered floor joists
Foundation
wall
LS90
Gusset
Angles
T
span for this application is
feet. This maximum span wou
require two 1/2-inch lag screws
between each deck joist if they ar
elevation and plan views detailing how a deck ledger shall be attached to a cantilevered fl
system.
Span > 4’ – Max. span 10’
Double joists
shall be of
sufficient cross
section to carry
header
Double header
shall be of
sufficient cross
section to
carry tail joists
framing into it
and will have
hangers on
both ends.
Maximum
header span
shall be 10’.
Foundation wall
Sill plate
House rim joist
Tail joists
Headering off a cantileve
r
F
or bay window which
extends beyond the ext
wall of the house may be
accomplished by headering
across the chimney or bay
window area with a double
header attached to double
joists on each side.
Doubling of these me
is required when the header
span is greater than 4 feet.
The double joists and
header shall be of suffi
cross section to carry the
tail joists framing into the
header.
8
The header shall be supported on each end by a double joist hanger when the header span
exceeds 6 feet. Tail joists over 12 feet long shall be supported at the header by joist hangers. A
space shall be provided between the doubled framing members and the house to allow for water
drainage and air circulation.
Joist and Beam Spans
Floor joists and beams have certain
span capabilities based on the size,
grade, species and spacing of the
material used for the joists or beams
and the loads that are imposed on
them. Deck joists are required to be
designed for 40 pounds per square
foot, just like a residential floor.
Most joist material used for building
decks is No. 2 and better, treated
Southern Pine. There are two sets of
spans for treated Southern Pine
shown in the table on the right. The
visually graded column is the one to
use. The wet service column is for
applications where the wood is going
to be wet for an extended period of
time. Deck material gets wet and
then dries out, so it is not considered
wet service.
Table 5
21-221-912
2 x 12 18-1018-1016
15-515-524
17-518-012
2 x 10 15-1016-116
13-113-124
13-814-212
2 x 8 12-512-1016
10-211-024
7-108-624
9-59-916
10-410-912
2 x 6
No.2
Wet Service
No. 2
Visually Graded
Spacing
inches o.c.
Size
inches
Treated Southern Pine Span Tables
Floor Joists — 40 psf Live Load, 10 psf Dead Load,
l
/360
Design values for dimension lumber are based on normal use conditions (moisture content 19%).
These values are intended for use in covered structures, or where the moisture content in use doe
s
not exceed 19% for an extended period of time.
To find the span capabilities
for the deck joists, find the
size of material being used
and the on-center spacing.
Then read down under the
No. 2, visually graded
column to find the
appropriate span. Joist spans
are measured from
unsupported edge to
unsupported edge. See
Figure 10 for a visual
representation of how a joist
span is measured.
. . . .
Joist span
(Measured from unsupported edge to unsupported edge)
HOUSE
Joist span measurement and
beam to post connection
6x6 post notched for beam
. . . .
Rim joist is the beam in this application
Figure 10
Remember that the ends of the joists will need to be properly supported. If they are running
between the ledger and a beam, they will need joist hangers on both ends.
9
Calculating beam spans is a bit
more complicated than floor
joists. First, the tributary width
supported by the beam must be
determined. For simple spans
the tributary width is 1/2 the
joist length. For a center beam
the tributary width is the sum
of 1/2 the span from each side.
If there is a cantilever, we add
in the total length of the
cantilever. Note that 2x8 and
larger floor joists cannot
cantilever more than 3 feet.
Once the tributary area has
been determined, the beam
span can then be determined using
Figure 11
HOUSE HOUSE
a/2 b/2
ab a
Overhang
d
a/2 d
tt
Overhang
ad
ab
a/2 d
t
a/2 b/2
t
Joist (typ.)
Beam (typ.)
A. t = a/2 + b/2
B. t = a/2 + d
C. t = a/2 + b/2 D. t = a/2 + d
Tributary load width (t) for deck beams
Overhang, “d” shall
not exceed 3 feet
Tables 6 or 7. Decide what will be used for the beam and check the span based on the tributary
load width. If 2 – 2x10’s are going to be used as the beam and the tributary area of the beam is 7
feet, the maximum span for the beam is 9 feet, 2 inches.
4-34-54-95-15-76-27-07-88-72x10
3-43-63-94-04-34-105-56-27-22x8
2-62-82-103-13-43-84-24-95-72x6
7-68-08-58-109-510-010-1011-1012-10(3)2x8
9-29-710-010-711-211-1112-1014-115-7(3)2x10
10-911-211-912-413-113-1115-015-518-3(3)2x12
7-07-47-88-18-59-29-1010-912-0(2)2x10
8-28-79-09-510-010-811-612-714-0(2)2x12
5-5
4-1
12’
7-2
5-7
8’
6-9
5-2
9’
6-3
4-9
10’
5-10
4-5
11’
7-8
8-39-110-1(2)2x8
5-11
6-57-07-10(2)2x6
7’
6’5’4’
Tributary load width (ft)
Beam size
40 lb/ft
2
live load – 10 lb/ft
2
dead load
Maximum beam spans for Treated Southern Pine
Spans are distances in feet-inches between centers of posts or supports. Grade is No. 2 or Better.
Number in parentheses is number of full-length nailed laminations.
When multiple members are used, they
must be attached so they act as one. This
requires nailing the members together w
10d nails at 16 inches on-center stagge
ith
red.
a single Cedar 4x10 were going to be
of
If
used instead of a built-up treated beam,
then Table 7 would be used. In the case
our 7 foot tributary area, a 4x10, which by
the way, is not
the same as 2 – 2x10’s, has
a span capability of 8 feet, 11 inches.
Table 6
A beam should always be supported
directly by the columns beneath it. This is
usually accomplished by notching the
beam into the post so there is direct wood
to wood bearing. Note 6x6 posts are
recommended if the beams are to be
notched into the posts.
a
4-34-54-84-115-25-66-06-77-44x6
6-16-56-107-37-108-89-84x8
7-27-67-118-48-119-810-711-104x10
8-48-89-29-910-511-312-413-94x12
5-75-106-26-77-07-78-39-36x8
7-77-118-48-99-39-1110-911-913-26x10
12’8’ 9’ 10’ 11’7’6’5’4’
9-29-710-110-711-312-013-014-315-116x12
Spans are distances in feet-inches between centers of posts or supports. Grade is No. 2 or Better.
Table 7
5-75-10
6-10
7-11
5-4
Tributary load width (ft)
Beam size
40 lb/ft
2
live load – 10 lb/ft
2
dead load
Maximum beam spans for Redwood
nd Western Red Cedar
10
However, there are times when a beam
must sit on top of a post. In these cases
there must be a positive connection
between the post and the beam.
Sometimes a 2x scabbed on the s
connecting the beam to the column is
sufficient, but metal connectors are als
available. See Figure 12 for different
ways to connect beams to posts.
ide
o
ote that beam spans are
d
f 2 feet
the beam is not notched into
on is
Figure 13
y
ut, since this type of connection is
e been
m
,
Figure 14
Figure 12
POST-TO-GIRDER CONNECTIONS
Beam
Beam span
Measured from center of support to center of support
Many times the outside rim joist acts as
a beam and then it must be designed as
a beam. In most cases, this means at
least doubling the outside rim joist.
2’
Max.
cantilever
for beam
Measuring a beam span
N
measured differently than joist
spans. A beam span is measure
from the center of support to the
center of support. Also notice
that a beam may only be
cantilevered a maximum o
beyond the support.
If
the post then the structural
performance of the connecti
limited to the capacity of the
bolts. In this case, the tributar
area that can be safely supported by the beam is greatly reduced. This type of connection should
be avoided if at all possible. Notching the beam into a 6x6 post or sitting the beam directly on
top of the post allows direct wood to wood bearing, and this will always provide better support.
Unnotched
post
Beam-to-post connection
The structural
performance of this
type connection is
limited to the capacity
of the bolts.
Because this connection is
limited by bolt capacity,
there is a maximum
tributary load area that
can be safely carried
by each beam-to-post
connection.
See tables for tributary area limitations for bolted connections
B
occasionally used, Tables 8 and 9 hav
provided showing the reduced area of deck
that can be supported when attaching the
beam to a post using only bolts to support
the load. Note that the tables specify the
size and number of bolts for use with
various size beams and posts. The bea
sizes in these tables are all based on No. 2
treated Southern Pine.
11
344440
Three-bolt connection (2x10, 2x12)
163040
Two-bolt connection (2x6, 2x8)
Redwood
&
Western Red Cedar
Southern pine
Tributary load area (ft
2
)
Live load (lb/ft
2
)
Limitations in tributary load area for beam-to-post connections
using 4x4 or 6x6 posts and 1/2-inch-diameter bolts.
406340
Three-bolt connection (2x12)
274240
Two-bolt connection (2x8, 2x10)
Redwood
&
Western Red Cedar
Southern pine
Tributary load area (ft
2
)
Live load (lb/ft
2
)
Limitations in tributary load area for beam-to-post connections
using 6x6 posts and 5/8-inch-diameter bolts.
Table 8 Table 9
. . . .
Joist span
(Measured from unsupported edge to unsupported edge)
HOUSE
Cantilevered joist detail
6x6 post notched for beam
(2) – 3/8” bolts and
washers for stability
or other approved
mechanical fasteners
Using 2x8 or larger
joists @ 16” o.c. a
cantilever cannot
exceed 3 feet
Back span on cantilever must be a minimum
of twice the cantilevered distance
Solid
blocking
Cantilevered Decks
It is often desirable to cantilever a
deck for aesthetics or for other
reasons. Certain considerations
must be taken into account when
using a cantilever. Deck joists 2x8
and larger may be cantilevered a
maximum of 3 feet beyond the
supporting beam as shown in
Figure 15. The back span for a
cantilever must be a minimum of
twice the cantilevered distance.
Figure 15
UPLIFT
UPLIFT
Joist must be continuous
over support
Potential
Concentrated
Load
Fulcrum
Beam
Post
Steel Twist Strap
Joist
First
Internal
Post
Cantilevered connection
..
Effect of
concentrated
load on
overhang
produces uplift
at interior
support
. .
Figure 4
A concentrated load on the end
of the cantilever has the effect of
producing uplift on the joists at
the first interior beam support or
at the attachment to the house.
When a deck is cantilevered, the
connection to the exterior wall of
the house or other framing
members such as a beam shall be
designed and constructed to r
uplift resulting from the full liv
load acting on the cantileve
portion of the deck. One way of
resisting these loads is with a
steel twist strap at each end to
prevent uplift.
esist
e
red
Figure 16
The beams in Figures 15 and 16 are notched into opposite sides of a 6x6 post. Due to the
separation of the two members that make up this beam, solid blocking needs to be placed
12
between the two beam members every 4 feet so they may be securely nailed together in order for
them to act as one unit.
Guardrails
For obvious safety reasons, guardrails are required when the deck floor is more than 30 inches
above another floor or the grade below. The guardrail shall not be less than 36 inches in height.
Open sides of stairs with a total rise of more than 30 inches above the floor or grade below shall
have guards not less than 34 inches in height measured vertically from the nosing of the treads.
The perimeter support posts can be incorporated into the railing of the deck. The posts extend
from the footings to the top rail cap. Balusters or ornamental closures that do not allow a 4-inch
diameter sphere to pass through are used to fill in between the posts. These balusters in
combination with the cap rail and bottom rail transfer the loads to the posts. In order to do this
successfully, the main
railing posts should be
spaced approximately 6 f
apart. The advantage of
this design is that the full
length of the post resists t
rail load.
eet
he
oint
sure the railing can support
he guardrail in-fill components which consist of the balusters or panel fillers shall be designed
hen guardrails posts are not a continuous part of
g
t in
Guardrails and handrails
shall be designed to support
a single 200 pound
concentrated load applied
in any direction at any p
along the top. This is to be
6”
4”
4”
Handrail – Required on
one side of stairs with
4 or more risers 34” –
38” above stair nosing
Guardrail – Min.
36” height where
deck floor exceeds
30” above grade
Cannot pass 4” sphere
between balusters or
the bottom rail and
floor
Concrete landing
Cannot pass 6” sphere
through triangle formed by
riser, tread and bottom rail
3’
Guardrail detail
Figure 17 the loads of people leaning
on or running into it.
T
to withstand a horizontally applied load of 50
pounds distributed over a 1 square foot area.
200 lb. load
Post
W
the support post system, they must be attached so
they can withstand the prescribed loads without
twisting the rim joist. It is therefore necessary to
be sure the rim joist is blocked so it cannot rotate.
Lag screws into the ends of the perpendicular
joists or blocking are the proper connectors for
this purpose. Nails into the end grain of the
framing lumber will simply withdraw allowin
the rim joist to twist. Figure 18 shows the
reaction load that is imposed on the top bol
various size rim joists when the code prescribed load is applied.
Figure 18
36”
4x4 Post for railing
‘P’
Upper
lever arm
Lower
lever arm
2”
2”
Reaction at ‘P’ –
2x6 – ‘P’ = 2,371 lb.
2x8 – ‘P’ = 1,648 lb.
2x10 – ‘P’ = 1,248 lb.
2x framing
1/2” bolts
loaded
to Code
13
Figure 19 shows a plan view of the connection details for attaching the railing posts to the rim
joist and the rim joist to the deck joists. Two lag screws in the deck joists or blocks on each side
of the post are necessary to prevent the r
from rotating unless the post is block
from behind and lagged to a joist
perpendicular to the rim joist. Use 1/2-
inch diameter bolts when attaching 4x4
railing posts to the rim joist so it canno
work loose over time. This is especial
true when the posts are being attached to
the outside edge of the rim.
im
ed in
t
ly
he triangular opening formed by the
at
to be of such a size that a 6 inches
h.
tairs
tairways shall have a minimum width
t
rs are
d
s.
T
riser, tread and bottom rail of the guard
the open sides of a stairway is permitted
2x Deck joists
Full depth 2x
blocking
Reinforced Post Connections
(Plan view)
Deck rim joist
2
1/2” bolts
2 – 1/2” lags
in each side
All nails are 16d
2
1/2” la
g
s
Figure 19 diameter sphere cannot pass throug
S
Figure 20
Reinforced Post Connections
(Three dimensional view)
The leverage from a deck railing post will twist the rim joist unless the rim joist
is securely fastened to the joist ends or perpendicular blocking. 1/2” lag screws
are recommended for resisting code design loads.
Rim joist
S
of 36 inches. The maximum riser heigh
shall be 7-3/4 inches and the minimum
tread depth shall be 10 inches as
measured in Figure 21. Open rise
permitted provided the opening between
the treads does not allow the passage of
a 4-inch diameter sphere. The opening
between adjacent treads is not limited on
stairs with a total rise of 30 inches or
less. The greatest riser height and trea
depth within any flight of stairs shall not
exceed the smallest by more than 3/8-
inch.
There shall be a minimum of two stringers
where the spacing between them is 24 inche
This requires the treads to overhang 5 inches
beyond each stringer. Three stringers may be
used where the outside members are placed 36
inches apart and a third is centered in between.
Now the treads are supported on the ends and in
the center. This gives us a stronger set of stairs
and allows us to meet the concentrated load
requirements.
Figure 21
Riser height
Stair Measurements
Stair Measurements
R314.2 Treads and risers.
The riser height shall be
measured vertically between
leading edges of the
adjacent treads.
Tread depth
R314.2 Treads and risers. The tread depth shall be measured
horizontally between the vertical planes of the foremost projection
of adjacent treads and at a right angle to the tread’s leading edge.
Nosing
R314.2.1 Profile. The radius of curvature at the leading edge
of the tread shall be no greater than 9/16 inch. A nosing not
less than ¾ inch but not more than inches shall be
provided on stairways with solid risers.
Nose
to nose
14
The stair stringers shall be
2x12, No. 2, treated Southern
r
nd
e toe-nailed to a backer or
An
be
oncrete. The bottom of the stringers shall then be notched over a treated 2x4 sleeper which
ngers also have a certain span capability. When using 2 stringers to support the stairway,
e maximum span for the stringers is 5 feet. When using 3 stringers the maximum span is
r manner meets the 300 pound concentrated load requirement on the
eads. If the same material that is being used for the decking is going to be used for the stair
andrails
quired on stairs
ith four or more risers. The
ll
t
Figure 22
3’
Stringers notched over treated
2x4 sleeper which is attached
to landing locks in bottom of
stringers
Concrete landing is recommended – it
shall support the heel cut of the stringers
.
.
.
Top of each stringer is toe-nailed
(typical) and supported by
Simpson LS70 Gusset Angle or
equivalent on one side, or sloped
hangers
Stringer Span (SS)
Max. SS = 5’ for 2 stringers
Max. SS = 9’ for 3 stringers
Min. 2x12 Treated SP stringer
Column attached to stringers
this may be an integral part of
the guard rail system
Stringer Span (SS)
Stair Stringer Detail
Stair Stringer Detail
Pine. They must not be ove
notched when cutting in the
rise and run. The cuts in
these notches must end at the
inside corners and not exte
beyond that corner or the
stringers will be weakened.
The top of each stringer shall
b
rim joist and then supported
by Simpson LS70 gusset
angles or their equivalent on
one side of each stringer.
alternate method would be to
use sloped hangers.
The bottom of these stringers shall rest on a landing. It is recommended that this landing
c
shall be attached to the landing or the stringers could be notched so they would lock in behind
the concrete landing itself. Either way effectively locks the stringers in place so they cannot
move.
The stri
th
increased to 9 feet. The span is measured horizontally from point of support to point of support.
See the diagram on the left.
Spacing the stringers in eithe
tr
treads, see Table 1 for span capabilities.
H
Figure 23
Type I. Handrails with a circular
cross-section shall have an
outside diameter of at least 1-
1/4” and not greater than 2”.
If the handrail is not circular it
shall have a perimeter
dimension of at least 4 inches
and not greater than 6-1/4
inches with a maximum cross
section dimension of 2-1/4
inches.
Minimum 1-1/2” clearance between
handrail and adjacent framing.
A 2x2 complies
with the code
requirements for
a handrail if it
runs continuous
the full length of
the stairs and
the ends are
returned.
Handrail geometry
Handrails are re
w
handrail shall be continuous the
full length of the stairs and sha
start at a point directly above the
top riser of the flight and continue
to a point directly above the lowes
riser in the flight. The ends of the
handrail shall be returned to the
posts at the top and bottom of the
stairs.
15
The handrail shall be between 34 inches and 38 inches above the nosing of the treads and shall
arance of 1-1/2
ed
other part of the process. These inspections are done as a service to the
omeowner and are required for all decks. Inspections should take place when various phases of
ection
r hole inspections may be required before the concrete is placed. Remember that
ry set concrete is not approved by most concrete manufacturers. The concrete needs to be
n) inspection may be required if the under-floor framing and
onnections cannot be easily inspected during the final inspection. A final inspection is required
, try to call 24 hours in advance to set up a time for the inspector
make his visit. The builder or homeowner is not required to be present for the inspections but
be provided on at least one side of the stairway. There shall be a minimum cle
inches between the handrail and adjacent framing. Type I handrails shall have a circular cross-
section with an outside diameter of at least 1-1/4 inches but not greater than 2 inches. If the
handrail is not circular it shall have a perimeter diameter of at least 4 inches and not greater than
6-1/4 inches with a maximum cross section of 2-1/4 inches. This means 2x2 lumber with eas
edges will meet the requirements of the code.
Inspections
Inspections are an
h
the construction are completed. Where a deck is too close to the ground to verify the conn
between the ledger and the house at the time of the inspection, then the deck shall be self-
supporting.
Footing or pie
d
properly mixed with the prescribed amount of water prior to placing in order for it to work
properly and to meet code.
A separate framing (rough-i
c
after all the work is complete.
When scheduling an inspection
to
they are welcome to be there if they would like to be.
his publication was produced by TimberTek Consulting and is endorsed by the Johnson County Building Officials
ssociation. It is published by the Johnson County Contractor Licensing Program for distribution throughout
Johnson County. Jurisdictions within Johnson County wishing to obtain copies of this publication for distribution in
their community should contact the Johnson County Contractor Licensing Program in Olathe, Kansas.
T
A
16
Plan
17
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