2018 MBP Deck Tip Sheet�MyBui ldi ngPermit.com
a service of eCityGov.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 ledge
connection options
Joist
Joist
Decking
Von fy span ratings of
ptoposod docking.
Joist Overhang
24" maximum.
Joist Spacing F
See span table and
footing schedule. `f\mil
4x4 min up to 8' 0' height
5x6 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
� J
i
y Joist Span
See span IADIe
Beam
Note: Guards are See span table
required when the deck
walking surface is more Footing
than 30" above grade. Soo span table and
g footing schedule.
MyBuildingPermit.com I Basic Deck
eCityGounet
M05 -2 eCllyGovAlliance
/�MyBui ldi ngPermitxom
a service of eCftyGov.net Construction Tip Sheet 05
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
Existing building 4" in diameter cannot
ssystems to onents
hdall be per manufaceck turer.
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 o Table on ge 3 for
Yy" spacing
J
recommended `
f BeamSizeand Spans
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
post exceeds 48". See detail
on page 7
the existing building
passes under the
proposed deck, or if there
For post size and maximum
allowable height, see page 4
Is 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"clear
Minimum
=1�111
i1�IlHll—II II-�..
- (2) h4 ea. way, 3" clear
depth of
footing 12"
�I�II�II-1
IE311�11=111�
°.
_ tobottom offootin
I - Fooling to bear on
AWN
I 9
ARmi-L„—_r—
II undisturbed earth.
MyBuildingPermit.com I Basic Deck
eCityCounet
M05 -�' aCllyGovAllianca
�MyBui ldi ngPermitxom
a service of eCityGov.net
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
12
14
1 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
2x 10
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 c,d,e
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.
January 14, 2022
MyBuildingPermit.com I Basic Deck
eCityGounet
2d05 � aCllyGavAlliance
,000w�'yBui ldi ngPermit.com
a service of e0tyGov.net
Construction Tip Sheet 05
Maximum Deck Post Height
Tributary 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
1 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
Grade
III „� 1 21 III
6
Thickness
per Table Q
Note: Posts must be Width
centered on or in footing per
Table
January 14, 2022
— Manufactured post connector
12"
t1"
d a
G d
112" diameter
through -bolts in both 4" gravel
directions
Note: not screws
MyBuildingPermit.com I Basic Deck
Typical P.T. post
Min. 12" of
embedment
eCityCounet
M05 � aC11VCovA 1ianca
�MyBui ldi ngPermitxom
a service of eCityGov.net
Deck Ledger and Connections
Construction Tip Sheet 05
Deck Ledger Connection to Band Joist
On -Center Spacing of Fasteners inches
Joist Span c
(feet)
'/2-inch diameter lag
screw with 1/2-inch
maximum sheathing b,c,e
'/2-inch diameter bolt
with '/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 a
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.
January 14, 2022
MyBuildingPermit.com I Basic Deck
eCityGounet
2d05 � aCllyGavAlliance
�MyBui ldi ngPermitxom
a service of eCityGov.net
EXTERIOR SHEATHING
EXISTING STUD WALL
Existing 2x BAND JOIST
OR ENGINEERING RIM
BOARD
Construction Tip Sheet 05
2" MIN o
DECK JOIST
S MAX
LAG SCREWS OR BOLTS
2' MIN
• ='t'• : �'/�•. I JOIST HANGER
Lag screw or bolt
2" min.
5" max.
"2" min.
Minimum edge distance for
specialized screws. See
manufacturer's technical bulletin.
Hold-down or
tension device
with 1500 #
capacity
Flashing
Dock Joist
January 14, 2022
Ledger
Stagger fasteners in 2 rows
S 112" min. for 2x8
6 112" min. for 2x10
7 112" min. for 2x12
' 1, 3/4" min.
Distance can be reduced to
4 112" 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.)
Option # 1
Floor sheathing nailing
at 6' o.c. (max) to joist
with hold-down.
Sheathing
Siding
Flashing
Decking
Joists
Joist Hangers
Treated 2x ledger
FloorMst 750# capacity holddown device
at 4 locations evenly distributed
along the deck and within 2 ft of
each end. Install per manufacturer
Fully threaded 3/8" diameter lag screw)
predrilled with a minimum of 3 in Option # 2
embedment into solid framing.
MyBuildingPermit.com I Basic Deck
2' min.
Floor joists
eCityGounet
2d[l5 � aCllyGavAlliance
�My6ui ldi ngPermitxpm
a service of eCityGov.net
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) 10d — 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
Beam spllces must occur
aver pasts witlr 1-112" min- bearing
Corroslon resistant, rnin.
metal columns cap.
Girder beam
Fallow rnanufacturer's
zi
Installation instruct,ions,
45�
4 x 4 knee brace
{11 } 318" diameter Mru-bolt or 112 "
Alternate knee Brace Detail:
lag screws with washers, top 8. bottom
2x4 knee brace face nailed ea- side of `
(typical)
post and beam with 4-1$¢ nails at each
Pressure treated
face and connection
woad post
January 14, 2022
MyBuildingPermit.com I Basic Deck
eCityGounet
2d05 � aCllyGavAlliance
,000w�'yBui ldi ngPermit.com
a service of eCityGov.net Construction Tip Sheet 05
Guards & Attachment
Guards are required when the deck is more than 30 inches above grade.)
2x2 Baluster, typical
6-0" max. spacing
2x5 or 5/4 board ail cap: attach
to guard post with (3) #12 by 3"
long screws or (3) 15d 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
Do Not Notch
2 x 8 nominal rim or outside
joist, minimum
2 5/8" diameter openings shall
Attach balusters at top and bottom with
through -bolts not allow the
(1) #8 wood screw or (2) 8d post -frame
and washers passage of a 4"
threaded nails with 0.135 nominal
diameter sphere
diameter
16.
max A
O.D. galvanized bolt
or threaded rod w/
nuts & washers
2'/i' min a ad 5" max
Min. 1800#
tension device
5/s" O D. galvanized bolt
or threaded rod wl
nuts & washers
2x8 min. deck 2"min I
joists & rims 2,�minand 5"max"
2"min
4x4 min. post
@ 60" o.c. max., Typ
2"min
Section A
2x8 min. blocking
2"min
Now:
Use above details for guard connections or provide engineered Min. 1800# tension straps
design that shows Guards can resist a single concentrated load
of 200 Ibs 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
MyBuildingPermit.com I Basic Deck
eCityCounet
M05 � aCIIVGavA Iianca