2018 MBP Deck Tip Sheet_..'11110000000�My6ui ldi ngPermitxpm
a service of eCltyGov.net Construction Tip Sheet 05
Basic Deck
This tip sheet reflects code requirements of the 2018 International Residential Code (IRC) with
Washington State Amendments.
Typical Deck
This document provides building code information applicable to prescriptive residential wood
deck design. You may need to hire a licensed architect or engineer to design a deck where any of
the following conditions apply:
• The deck serves other than a one- or two-family dwelling building
• The deck design includes more than one level
• The deck will support a hot tub, spa or other heavy object, including heavy deck covering (such
as pavers)
• The walking surface is more than 14 feet above grade
• The deck ledger is attached to house overhangs, bay windows, bricks, stone, or concrete block
• The deck is bearing on ground with a slope greater than 1 foot horizontal for every 1 foot
vertical
• The deck is self-supporting (not attached to an exterior wall)
See Detail f for ledger
connection options.
Joist
Joist
Decking
Von fy span ratings of
ptoposod docking.
Joist Overhang
24' maximum
i�
Joist Spacing �
See span table and
tooling schedule. A;a�per/
4x4 min up to 8' 0' height
M min. up to 10' 0' hoight
Non -corrosive metal
post/beam connector
Continuous solid blocking
between joists
Beam Overhang
24" maximum
January 14, 2022
See Page 6
for Ledger
Attachment
i J
y Joist Span
See span table
Beam
Note: Guards are See span table
required when the deck
walking surface is more Footing
than 30" above grade. See span table and
g footing schedule.
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Deck Construction Notes
• Design loading for decks is based on 60 pounds per square feet (PSF) live load, 10 PSF dead
load, and 1500 PSF soil -bearing capacity.
• The illustrations and information in this tip Sheet may be used for decks whether or not they
require a permit. See Tip Sheet 0 for when a permit is required.
• All wood must be pressure -treated or naturally resistant to decay. Treat cuts, holes, and
notches with end -cut solution.
• Fasteners, hangers, nails, etc., must be stainless steel, hot -dipped galvanized, or as specifically
required for the specified wood preservative used. The coating weights for zinc -coated
fasteners to be in accordance with ASTM A 153. Provide documentation in the field showing
the required fastener protection for the wood chosen for your deck.
• You may modify any components of this Tip Sheet using accepted engineering practices. Any
modifications must be reviewed prior to permit issuance. All attachments must be per
manufacturer's installation instructions.
• Visit MyBuildingPerm it.com for additional Tip Sheets for stairs, handrails, and notching and
boring.
January 14, 2022
36" minimum high guard
with intermediate rails
Attachment of
spaced so that a sphere
pre -manufactured guardail
Existingbuilding 4" in diameter cannot
9
systems to deck components
shall be per manufacturer.
pass through (See Tip
Flashing Sheet 3).
Special blocking details may be
required by the reviewer.
See detail 1 on page
6 for ledger Refer table on page
attachment options 3 for Joist Sizes
See page 8 for guardrail
post connection
Decking and Spans
Secure ballusters with (1) #8d
\
wood screw top & bottom
Refer to Table on e 3 for
Ya" sparing
recommended
n
/ Beam Size and Spas
Note:
for drainage
Contractor to field
verify adequacy of
Knee braces are required if
solid lumber for ledger
distance from grade to top of
connection.
If an exit or egress from
onsta exceeds 48". See detail
page 7
the existing building
passes under the
posed deck, or if there
For post size and maximum
allowable height, see page 4
Ippros an existing patio under
the proposed deck, 6'-8"
minimum clearance must
be maintained. Please
Indicate openings In
existing wall in elevation
Manufactured post base cast in
footing
view.
Refer to Table on page 4 for
Footing Size
3,000 psi concrete (no special
inspection required)
Finished grade
1"dear
Minimum
I I
II I II I I '•.
I 2),14 ea. way, 3" clear
I I I —I
depth of
to bottom of footing.
footing 12"
IC 1 T 1
pl — Footing to bear on
T_,._-1
11 undisturbed earth.
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Construction Tip Sheet 05
When using the tables below, interpolation is allowed, extrapolation is not allowed.
Sizing of Structural Elements
Maximum Deck Joist Span a,c
Joist
Joist Spacing b
inches
Joist Back Span
Size
12
1 16
1 24
4
6
8
10
1 12
1 14
16
18
Allowable Joist Span
Maximum Cantilever (feet inches) Adjacent Joist Span feet
2x6
7-11
7-1
5-9
1-0
1-6
NP
NP
NP
NP
NP
NP
2x8
10-5
9-5
7-8
1-0
1-6
2-0
2-1
NP
NP
NP
NP
2x10
13-3
11-6
9-5
1-0
1-6
2-0
2-6
2-8
NP
NP
NP
2x12
15-5
13-4
10-11
1-0
1-6
2-0
2-6
3-0
3-3
NP
NP
a. Includes Incising Factor.
b. When using composite decking, refer to manufacturer's installation instructions for
maximum spacing of joists.
c. Spans based on Doug Fir -Larch, Hem Fir and Spruce -Pine -Fir, No. 2 grade, wet service
factor.
Minimum Beam Size
Deck Joist Span feet
6
8
10
12
1 14
16
18
Beam
Size cAe
Maximum Beam Span a,b,d (feet -inches)
4x6
5-2
4-6
4-0
3-5
3-1
2-10
2-7
4x8
6-11
6-0
5-3
4-7
4-1
3-8
3-5
4x10
8-5
7-4
6-6
5-10
5-2
4-9
4-5
4x12
9-10
8-6
7-7
6-11
6-4
5-9
5-4
6x6
6-6
5-7
5-0
4-7
4-2
3-9
3-5
6x8
8-8
7-6
6-8
6-1
5-6
5-0
4-7
6x10
10-7
9-2
8-2
7-6
6-11
6-4
5-10
6x12
12-4
10-8
9-7
8-9
8-1
7-7
7-1
a. Spans based on Doug Fir -Larch, Hem Fir and Spruce -Pine -Fir, No. 2 grade, wet service
factor.
b. If 2x built up beams to make 4x or 6x beams, they shall be fastened with two rows of 10d
(3-inch x 0.128-inch) nails minimum at 16 inches on center along each edge (507.5)
c. Beam depth shall be equal to or greater than the depth of intersecting joist for a flush
beam connection.
d. Beam cantilevers are limited to the adjacent beam's span divided by 4.
e. Includes incising factor.
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Construction Tip Sheet 05
Maximum Deck Post Height
Tributwy Area e
Post
20
40
60
80
1 100
120
140
160
Size c,d
Maximum
Deck Post Height a feet -inches
4x4
10-0
10-0
8-7
7-0
5-8
4-1
N P
N P
4x6
14-0
13-10
11-1
9-5
8-2
7-3
6-4
5-4
6x6
14-0
14-0
14-0
14-0
14-0
13-3
10-9
6-11
8x8
14-0
14-0
14-0
14-0
14-0
14-0
14-0
14-0
a. Measured from the underside of the beam to top of footing.
b. Based on Doug Fir, Hem Fir and Spruce -Pine -Fir, No. 2 grade, wet service factor.
c. Notched deck posts shall be sized to accommodate beam size.
d. Includes incising factor.
e. Area, in square feet, of deck surface supported by post and footing.
Footing Size
a
Tributary Area b
Side of Square
Footing (inches)
Diameter of a
Round Footing
inches
Thickness
(inches)
5
7
8
6
20
12
14
6
40
18
20
6
60
21
24
8
80
25
28
9
100
28
31
11
120
30
34
12
140
33
37
13
160
35
40
15
a. Footing dimensions shall allow complete bearing of the post.
b. Area, in square feet, of deck surface supported by post and footings.
12" min. frost depth
in allowable soils
Manufactured post connector
Typical P.T. post
12"
f1
Grade
„i III III ��� ���
Illa� ��� ��� ' ° „�11 ���,III
III III L
Thickness
per Table
"
Note: Posts must be
width
1/2" diameter
centered on or in footingper
through -bolts in both 4" gravel
Min. 12" of
Table
directions
embedment
Note: not screws
January 14, 2022
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Deck Ledger and Connections
Construction Tip Sheet 05
Deck Ledger Connection to Band Joist
On -Center Spacing of Fasteners inches
Joist Span c
(feet)
1/2-inch diameter lag
screw with '/2-inch
maximum sheathing b,c,e
'/2-inch diameter bolt
with 1/2-inch
maximum sheathing c
'/2-inch diameter bolt
screw with 1-inch
maximum sheathing d
6
22
36
35
8
16
31
26
10
13
25
21
12
11
20
17
14
9
17
15
16
8
15
13
18
7
13
11
a. Ledgers shall be flashed in accordance with Section R703.4 to prevent water from
contacting the house band joist.
b. The tip of the lag screw shall fully extend beyond the inside face of the band joist.
c. Sheathing shall be wood structural panel or solid sawn lumber.
d. Sheathing shall be permitted to be wood structural panel, gypsum board, fiberboard,
lumber, or foam sheathing. Up to 1/2-inch thickness of stacked washers shall be permitted to
substitute for up to 1/2-inch of allowable sheathing thickness where combined with wood
structural panel or lumber sheathing.
e. For on -center spacing of specialized fasteners refer to the manufacturer's installation
instructions.
Placement of Lag Screws and Bolts in Ledgers and Band Joists
Minimum End and Edge Distance and Spacing Between Rows
Top Edge
Bottom Edge
Ends
Row Spacing
Ledger'
2 inches d
3/4 inch
2 inches b
1-5/8 inches b
Band joist `
3/4 inch
2 inches e
2 inches b
1-5/8 inches b
a. Lag screws or bolts must be staggered from the top and bottom along the horizontal run.
See figure below.
b. Maximum 5 inches.
c. For engineered rim joists, the manufacturer's recommendations govern.
d. The minimum distance from the bottom row to the top edge of the ledger must be in
accordance with figure below.
e. 2 inches may be reduced to 3/4-inch when the band joist is directly supported by a
mudsill, header, or by double top wall plates.
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EXTERIOR SHEATHING
EXISTING STUD WALL
Existing 2x BAND JOIST
OR ENGINEERING RIM
BOARD
2" min.
4--
5" max.
Hold-down or
tension device
with 1500 #
capacity
Flashing
II=7 .. T
January 14, 2022
2" MIN
15JN' vPl
F MAX
2" MIN
Lag screw or bolt
�2" min.
Minimum edge distance for
specialized screws. See
manufacturer's technical bulletin.
Ledger
Construction Tip Sheet 05
DECK JOIST
SCREWS OR BOLTS
JOIST HANGER
Stagger fasteners in 2 rows
5 112" min. for 2x8
6 1/2" min. for 2x10
7 112" min. for 2x12
--- �- 3/4" min.
• Distance can be reduced to
4 1 /2" if lag screws are used or
if bolt spacing is reduced to
that of lag screws to attach 2x8
ledgers to 2x8 band joists
Detail 1 — Ledger Attachment for Lateral Loads
(Knee braces are required on posts greater than 4 feet in height.)
Sheathing
1-17
S ding
IFloor sheathing nailing Flashing
al 6' o.c (max) to foist
Option # 1
with hold-down. Decking
Joists
Joist Hangers
tW Treated 2x ledger
Floorloist 750# capacity holddown (
at 4 locations evenly distr
along the deck and within
each end. Install per manufa
Fully threaded 3/8" diameter IF
predrilled with a minimum oT a in
embedment into solid framing.
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2' min.
or joists
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Construction Tip Sheet 05
Connections and Fasteners
(All fasteners, nails, bolts, screws, and connectors must be corrosion resistant.)
Type of Connection:
Notes:
Manufactured Connectors
Follow manufacturer's instructions
Post to Footing
Post base is required
Post to Footing (High Winds)
Consult with jurisdiction about additional uplift loads where wind
exposure is greater than Risk Category B
Post to Beam
Connector is required
Ledger to House Framing
See information on Sheet 5 and Sheet 6
Joist to Beam or Girder
3 8d — Toe nailed
Blocking or Bridging to Joist
2 1Od — Toe nailed at each end
Wooden Deck Boards
2 8d threaded nails oR 2 No. 8 screws
Composite Decking
Follow manufacturer's instructions
Post to Beam Connection with Knee Brace
(Knee braces are required on posts greater than 4 feet in height.)
Or 113 the height of the post.
whichever is greater -- --
Corrosion resistant,
metal column cap.
Follow manufacturer's
installation instructions
c
E
N
Alternate Knee Brace Detail:
2x4 knee brace face nailed ea. side of
post and beam with 4-16d nails at each
face and connection
January 14, 2022
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Beam splices must occur
over posts with 1-1/2" min. bearing
Girder beam
4 x 4 knee brace
(1 ) 3/8" diameter thru-bolt or 112 "
lag screws with washers, top & bottom
(typical)
Pressure treated
wood post
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Guards & Attachment
Guards are required when the deck is more than 30 inches above grade.)
spacing
9■1■B■B■1■8■B■8■I
2 5/8" diameter
through -bolts
and washers
Openings shall
not allow the
passage of a 4"
diameter sphere
max A
�- 2x2 Baluster, typical
2x6 or 5/4 board ail cap: attach
to guard post with (3) #12 by 3"
long screws or (3) 16d threaded
nails with 0.148 nominal
diameter
2x4 top and bottom; attach to
guard post with (2) 8d threaded
nails or (2) #8 wood screws
>_ 2 1/2" long on inside face
4x4 guard post, typical
nr% nl.,+ nl.,r..h
2 x 8 nominal rim or outside
joist, minimum
�— Attach balusters at top and bottom with
(1) #8 wood screw or (2) 8d post -frame
threated nails with 0.135 nominal
diameter
%8" O.D. galvanized bolt
or threaded rod w/
nuts & washers
2, z' min and 5" max
Min. 1800#
tension device
5/s" O.D. galvanized bolt
or threaded rod w/
nuts & washers
2x8 min. deck 2"min
joists & rims 2,/ min and 5" max
2"min
4x4 min. post
@ 6'0" o.c. max., Typ
2"min
Section A
2x8 min. blocking
2"min
Use above details for guard connections or provide engineered Min. 1800# tension straps N
design that shows Guards can resist a single concentrated load
of 200 ,1b, applied in any direction at any point along the top and Section B
have attachment devices and supporting structure to transfer this
load to appropriate structural elements of the building per IBC
sec 1607.7.1.1
January 14, 2022
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