Report OFFICE COPY '51-7-6)1(---°42-6-
. lI�U�S /-� r�
��� �� Deck Design Guide
, •
:_!.::. One and Two Family Residential Dwellings
The Bureau of Development Services (BDS) is providing this informa-
tion to help you design your deck, obtain a building permit and pass CONTENTS
inspections.The standards and details in this Guide will help you Do I Need A Permit? 2
determine how large the footings, beams,joists, posts, and ledgers
•r need to be; how to build lateral bracing,stairs,and railings; and how What Plans Do I Need? 2
to fasten all of the pieces together.This Guide does not take into ac-
. > count conditions which may affect your deck design such as drainage General Notes 3
conditions, slope conditions, or decks supporting loads in excess of Footings,Beams,Joists,and Posts 4
CC c the standard uniform loads. Depending on your specific situation,
ua 0 you may need to hire a licensed architect or structural prior engineerThe Ledger Board 7
cu to approval.
VI 9
0 You may include all, orpart of the pre-approvedFreestanding Decks 11
design standards and
W -2 details in this guide with your building permit plans for decks that are: Lateral Support of Decks 11
. +° • For one-and two-family dwellings
ttFraming Connections 12
Cl- 0 • Single-span t "S hJ\,../
0 Footings 13
• All on one level
1111 u.i • Not supporting a hot tub or spa Guardrails 13
u_ • • Not attached to house overhangs, bay windows, brick,stone or tairs
0 co concrete block Chimneys/Bay Windows 20
0
C ^ • Not more than 10 feet above the ground Deck Framing Plan 21
( ) • Not bearing on ground with a slope greater than 2 feet horizontal
= co for every 1 foot vertical Helpful Information 22
Q
M
W O
= "' Guard
II
_
m co. I Ledger 9
c) I
Z a
t.V cu
,,loll/
1++ ` Rim joist
0i i :� i _C � i � l � �
014
,� Niii
Ledger board
Q a Footing ,' attachment
a) i
1— m Grade
CC v „ '�;
CL. Q I\/I ti
Joist
l\Um 7t- \ ' Post to beam
connection
0
Built-up beam j>- V'
~ c--)
I1
v� DECK DESIGN GUIDE • 1
Introduction
Do I Need A Permit For My Deck?
A building permit is required for all decks that are more than 30 inches above
the ground at any point. See Brochure 3,Fences,Decks and Outdoor Projects.
Setbacks and Other Regulations?
For information on setbacks (how close a deck is to a property line) and other
regulations that may apply to your deck project, even when a building permit
is not required,see Brochure 3. Call Planning and Zoning at 503-823-7526 to , }
find out what zoning requirements apply to your specific property. 1 di .1
How Do I Get A Building Permit? `z:
See BDS handout, Brochure 1,Guide to Permits and Inspections.This handout
describes the building permit process from application to final inspection. I: lI ,,,,
,
What Plans Do I Need?
You may draw all your own plans and details without using this Guide,or you 3- n,
may use the pre-approved standards and details in this Guide to supplement
your plans. Refer to Brochure 6,What Plans Do I Need for a Building Permit?
for descriptions and examples of the plans needed to obtain a building permit
for a typical residential construction project. Since a deck can be a relatively
simple project,you will only be required to provide the plans listed below if
you use this Guide:
• Site Plan-You will need to draw a site plan.The Site Plan must show the
property lines, outlines of all existing and proposed buildings, paved areas F� —1y,�,s, �'.,� ,1�i� w
and decks on the lot, and the distances from your proposed deck to the ~' 104t,o 4 'f � , 417 ,
nearest property lines. See Brochure 6 for Site Plan requirements and a E ,,� 4.,,,is,;
sample Site Plan. _ y .. '
a�4 �;
• Elevation View-You will also need to draw an Elevation View,which is a ��
front or side view of your house and the proposed deck and the level of the q/,i 4 iy(j
::: ,
ground adjacent to the deck(see Brochure 6).
• Framing and Foundation Plan-You can draw your own Framing and Foun-
dation Plans (see Brochure 6) or you can complete the Worksheet andTypi-
cal Deck Plan at the end of this Guide.
• Cross Section and Details-You can draw your own Cross Section and
Details (see Brochure 6) or you can use the details in this Guide.Your plans �3- - `?; * '"
must include details of the following parts of your deck: , .
• Ledger board attachment
• Joist-to-beam connection
• Rim joist connection - *a)`
a
• Post-to-beam connection A ! ''
,
• Lateral support method 4" 4 ., b or. i..
• Guardrail height and openings
• Guardrail post attachment
• Stair and stair handrail details /' ;
• Post-to-footing connection
2 • DECK DESIGN GUIDE
; iii General Notes
4
1.All lumber shall be grade#2 Douglas-Fir, Hem-Fir, or better and shall be
I f, '. pressure treated (to resist insect and dry rot) in accordance with American
Y)•
. Wood-Preservers'Association Standards (Category). Deck surface and trim
,)£, ii material of redwood, cedar,or other wood with a natural resistance to de-
-- r• cay does not require pressure treatment.The level of treatment depends on
the use as follows:
t
" a. Decking material, railings,joists,and beams must be treated to a Cat-
trot
' ' egory UC3B (or must be other wood with a natural resistance to decay).
b. Posts and other woods located on, in,or in contact with the ground must
# r be a Category UC4B.
x ,' c.Any wood less than six inches above the ground or in contact with con-
'}�'` - crete must be a Category UC4A.
The level of preservative treatment is noted on the tags on the ends of the
wood members. Remember, any time you make a cut,treat the cut end of
the wood with a paint-on preservative. Cut ends expose the inner untreated
wood to potential moisture and insect damage.
` Hardwood and plastic or composite decking products may be substituted
for conventional wood decking, but installation and span lengths of the
substituted material must be in strict conformance with the product listing
ift ��.y 1 and the manufacturer's installation instructions. Copies of the manufac-
rt.
" + turer's installation instructions must be submitted with the building permit
.«r _ application.
2.All nails shall be common or box galvanized. It is recommended that com-
41,
mon nails be used.They have a thicker shank and are stronger than box
nails.
3.New pressure treatment methods use chemicals that will prematurely cor-
rode standard fasteners, hardware, and flashing when in contact with pres-
sure treated lumber; and as a result,fastener and hardware requirements
have changed. Note the following:
4' a ' a.All screws and nails shall be
�` , hot-dipped galvanized or stainless steel.
"
b.All hardware (bolts, nuts and washers,joist hangers, mechanical fasten-
ers, holdowns,tie plates cast-in-place post anchors,etc.) shall be gal-
�. vanized with 1.85 oz/sf of zinc (G-185 coating) or shall be stainless steel.
Look for products such as "Zmax"from Simpson Strong-Tie or"Triple
Zinc" from USP
I � i `� 41IJ1I) 4.All decking material shall be 2x4,2x6, or five quarter(5/4") boards.Attach
II
��� Iif ); decking to each joist with two 10d nails or two#8 screws. Decking may be
i ,# w placed from an angle perpendicular g p p ndicular to the joists to an angle of 45 degrees
"' to the joists. Decking must have a span length such that each board bears
on a minimum of two joists.
i 5.Headers over existing doors,windows or openings greater than six feet in
Alit, width that are located below a deck that will be attached to the house must
#"� ° { es, be checked to verify that those headers can support the additional load
added by the deck.
6.The bottom of all footings for decks that are attached to a house are to be
placed a minimum of 18 inches below the surface of the finished grade and
must bear on firm, undisturbed native soil.The bottom of footings for free-
standing decks may be at any depth on undisturbed native soil. Footings
adjacent to the top of a retaining wall must be set back from the wall a dis-
tance equal to the height of the wall,or be extend below grade an amount
equal to the height of the retaining wall.
DECK DESIGN GUIDE • 3
Footings, Beams, Joists and Posts
First, decide how long and wide you want your deck. (Note:The drawings in this Guide indicate square or rectangular
configurations, however, decks can be any shape as long as the longest joist and beam spans are used to determine the
beam,joist, and footing sizes.)Your deck can have up to a two-foot maximum joist and/or beam overhang. See Figures
1,2,and 3. Beams must be supported on each end by a post and cannot be supported with beam hangers off the house.
"A", , „ „ „
Use Table 1 to find the minimum beam,joist and footing sizes.Joists are identified as beams as' B, posts as C, and
footings as"D:' It is recommended that you first determine the joist span, and then note what beam and footing sizes
you will need. Optional overhang
The span of a joist is measured
from the centerline of bear10(
-
ing at one end of the joist to L
the centerline of bearing at
the other and does not include Blocking
overhangs. Maximum joist span
lengths are noted inTable 1.
See Figures 1 and 2 for joist Beam "B" Joist"A"
span types.
Post"C"
-
Footing "D"
2'-O" max. Joist span
overhang 1 (Min. span = 6'-O" with overhang)
AFig. 1:Joist span,deck attached at house
Optional overhang
.----- Blocking
II •- B NA �I
C
f D
2'-O" max. Joist span 2'-O" max. ,
overhang (Min. span = 6'-O" with overhang)
AFig.2:Joist span,freestanding deck
4 • DECK DESIGN GUIDE
Optional overhang
ie
MI N N N N N t
I
ItB A Beam splices at
interior post
' C locations only
D
I -14 6" min
-
I /
_ _I ___ _. J - - I
/ 2'-0" max. / Beam span / Beam span
overhang (Min. span = 6'-0" with overhang) /
AFig.3:Beam span
Table 1 provides you with the information to determine the minimum sizes of the footings, beams, and joists.The sizes
will depend on how big the deck will be and how many footings and posts are going to be used; how far the beam(s)
will span from post to post,or post to ledger;and how far the joist will span from beam to beam, or beam to ledger.
Note:The sizes, spans and spacing of the joists in Table 1 are the minimum/maximum allowed by code. If you want
your deck to be stiffer, increase the size, reduce the span,or reduce the spacing of your joists.
Note:The footings must bear on native soil.The footing details require a footing that is a minimum of 24 inches in
height so the bottom can be located a minimum of 18 inches below the finished grade and extend six inches above the
finished grade. If you have fill material that is greater than 18 inches deep,your footing will need to extend through the
fill to native soil. Footings for freestanding decks (those not attached to the house)are not required to be located 18
inches below the finished grade and can have a minimum thickness of eight inches.
Post sizes are 4x4 minimum for decks six feet or less above the ground and 4x6 for decks over six feet above the
ground. Use a minimum 4x6 post under all beam splices.
Mark the sizes,spacing and spans for the footings, beams,joists,and posts from Table 1 in the space provided below:
A. Joist Size: x , spaced apart.
B. Beam Size: x
C. Post Size: x , spaced apart.
D. Footing Size: x x .
Transfer your footings, beams,joists, and posts information above into the Deck Framing Plan at the end of this Guide
DECK DESIGN GUIDE • 5
71
TABLE 1
Ifhave have the they footings"D"
beamyouhaB thata is: postsandyou"C" canthen onlyyou minimumand size beand spacedcan a supportingandthe the posts
supporting the span the joist iyou can maximum of: must be a minimum size
beam spaced: joists: use is: of (WxWxH):
"
4x8 or(2) 2x8 6'-0" apart 6'-0" 2x6* 24" apart 13"x13"x24" deep or14" diameter x 24" deep
4x10 or(2) 2x10 8'-6" apart 6'-0" 2x6* 24" apart 15x15"x24" or
17" diameter x 24" deep
4x12 or(2) 2x12 10'-6" apart 6'-0" 2x6* 24" apart 16"x16"x24" or
18" diameter x 24" deep
4x12 11'-9" apart 6'-0" 2x6* 24" apart 18"x18"x24" or
20" diameter x 24" deep
4x8 or(2) 2x8 6'-0" apart 8'-0" 2x6* or 2x8 16" or 24" 14x14"x24" or
16" diameter x 24" deep
4x10 or(2) 2x10 8'-0" apart 8'-0" 2x6* or 2x8 apart part or 24" 16"x1618" diameter or
x 24" deep
4x12 or(2) 2x12 9'-6" apart 8'-0" 2x6* or 2x8 16" apart or 24" 18"x18"x24" or
apart 20" diameter x 24" deep
4x12 10'-9" apart 8'-0" 2x6* or 2x8 16" apart or 24" 18"x1
a x24" or
x 24" deep
apart
4x8 or(2) 2x8 5'-6" apart 10'-0" 2x8 or 2x10 16" apart or 24" 16" diameter"X24" or
x deep
apart
4x10 or(2) 2x10 7'-6" apart 10'-0" 2x8 or 2x10 16" apart or 24" 16"x16"x24" or
apart 18" diameter x 24" deep
4x12 or(2) 2x12 9'-0" apart 10'-0" 2x8 or 2x10 16" apart or 24" 18" diameter or
x 24" deep
apart
4x12 10'-3" apart 10'-0" 2x8 or 2x10 16" apart or 24" 20"x20"x24" or
apart 23" diameter x 24" deep
4x6 or(2) 2x8 5'-0" 12'-0" 2x10 or 2x12 16" apart or 24" 14"x14"x24" or
apart 16" diameter x 24" deep
4x8 or(2) 2x10 6'-6" 12'-0" 2x10 or 2x12 16" apart or 24" 16"x16"x24" or
apart 18" diameter x 24" deep
4x12 or(2) 2x12 8'-6" 12'-0" 2x10 or 2x12 16" apart or 24" 18"x18"x24" or
apart 20" diameter x 24" deep
4x12 9'-6" 12'-0" 2x10 or 2x12 16" apart or 24" 20"x20"x24" or
apart 22" diameter x 24" deep
16" apart 15"x15"x24" or
16'-0" 2x12
4x6 or(2) 2x8 4'-6" 17" diameter x 24" deep
16" apart 18"x18"x24" or
16'-0" 2X12
4x8 or(2) 2x10 6'-0" 20" diameter x 24" deep
4x10 or(2) 2x12 7'-6" 16'-0" 2X12 16" apart 20"x20"x24" or
23" diameter x 24" deep
4x12 9'-0" 16'-0" 2x12 16" apart 22"x22"x24" or
25" diameter x 24" deep
* 2x6 joists cannot be used where a guardrail is required.
6 • DECK DESIGN GUIDE
7
The Ledger Board
Decks that are attached to a house require a ledger board to be fastened to the house structure, and the deck joists are
fastened to the ledger. If your deck will be free-standing and not attached to the house, skip this section and proceed to
Free-Standing Decks.
There are several methods for attaching the ledger to the house, depending on how the house was built and how high
the deck will be located relative to the house's existing floor framing.The ledger can be fastened to the house band
board (or rim joist) (Figure 5 or 6),the wall studs (Figure 7) or a concrete wall (Figure 8).You will need to verify the ex-
isting conditions before you apply for a building permit. If you can't verify the existing conditions or if they are different
from Figures 5, 6, 7 or 8 then a free-standing deck is required (see Free-Standing Decks).
Siding and Flashings:The siding or exterior finish system must be removed to install the ledger board against the wall
sheathing.Two layers of continuous flashing must be properly installed to prevent water from getting into the wall
where the siding has been removed. See Figure 5.The flashing material may be copper(using copper nails),stainless
steel, galvanized steel coated with 1.85 oz/sf of zinc(G-185 coating), UV-resistant plastic,or self-sealing bituminous (tar)
"peel-and-stick"flashing.The first layer is attached directly to the exterior wall sheathing starting behind and above the
bottom edge of the building paper and siding, continuing straight down the face of the wall behind the ledger board
l' (before it is installed) and end-
Exterior wall sheathing .111
First layer flashing behind building ing on the outer face of the
and ledger board, and over sidin exterior wall siding or foun-
(15/32" max sheathing) g dation below the bottom of
Second layer"Z" flashing over top the ledger board. Self-sealing
Existing wall________•._ --><...1 and
--><...1and down face of ledger board bituminous peel-and-stick
flashing is ideal for the first
//AV/y/74 Decking over layer. Pre-formed Z-shaped
Existing 2X deck joist metal flashing is ideal for the
rim (band) „ outer,second layer of flashing.
4 2X ledger, same size It is installed after the ledger
2X floor joist_. \ as deck joist board and before the joists,
starting behind and above the
Joist hanger LUS26 bottom edge of the building
I (or equal) min. paper and siding, continuing
Existing wall framing I • 1/2" lag screws or down vertically to the top of
or concrete wall (2) #14X4"wood screws or the ledger board, bending
shown dashed I (2) 1/4"X4" Simpsonhorizontally to the outer face
( ) I SDS screws of the ledger board, and bend-
1, (or equal) at spacing "S" ing again vertically down the
face of the ledger board at
least 1/2:
A Fig.5:Attachment of Ledger Board to Band Board with Lag or Wood Screws
(See Fig. 12 for spacing and clearances)
Spacing"5"
Joist Span /2"dia.lag screws*! #14 X4"wood screws (2)Simpson SDS 1/4"X4"
0<span <8' 23" 10" 16"
8'<span < 10' 18" 8" 16"
10'<span_< 14' 13" 6" 12"
14'<span < 16' 11" 5" 9„
*The tip of lag screw shall fully extend beyond inside face of rim joist!From table R502.2.2.1 of 2011 ORSC.
Manufactured Wood Joists(MWJs): If the existing house floor joists are MWJs, and not /i4
solid-sawn lumber,you will need to submit a ledger attachment detail that is approved
by the MWJ manufacturer or a licensed engineer. Examples of MJWs areTJl, GPI and
LPI. See Figure 4. Older homes constructed with MWJs may have a plywood band .Fig•4:MWJ profile
board,while some newer homes may have 1 1/4-inch manufactured wood rim joists.
DECK DESIGN GUIDE • 7
(Exterior15/32" sheaIlk
thing Continuous(SeeFig. 5)flashing
max)
Existing wall
Existing 2X rim (band) Decking over
\-- ---- deck joist
ryk
_„
Ei
III_ 1.
,01111110.
Spacing 2X floor joist
Joist Span „S„ I I
2X ledger with 1/2" dia. bolts
0<span <_8 36 I
staggered at spacing"S".
8'<span <_10' 34" Existing wall framing Locate first bolt 2" from end
10'<span<_14' 24" or concrete wall-1,1 of ledger
14'<span <_16' 21" (shown dashed) I I
From table R502.2.2.1 of 2011 ORSC. I
A Fig.6:Attachment of Ledger Board to Band Board with Thru-Bolts
(See Fig. 12 for spacing and clearances)
Exterior sheathing
Remove siding at ledger
min. thickness = 3/8" I location prior to installation
Continuous flashing
(See Fig. 5)
Existing wall stud 1,01:1V //////Air A rr .0 % A
16[ 1" min.
IIII
Fasteners at 16" O.C. I
per table 2X ledger
IJoist span ►
Required fasteners to each
Joist Span stud or 16 inches o.c.max.
0<span <_8' (3)#10 x 5" wood screws
8'<span <_10' (4)#10 x 5" wood screws
10'<span <_14' (5)#10 x 5" wood screws A Fig. 7:Attachment of Ledger Board to Wall Studs with Screws
14' <span <_16' (6)#10 x 5" wood screws
8 • DECK DESIGN GUIDE
—:—T---- ' 'I 'm. ' 'umm'mImlmlmm...MlM.IlMM.M...I....M1IM.MMMl' '
Concrete
wall
Decking over
/deck joist
P!:
ft. 2" min.
!.
A
Joist Span Spacing
2X ledger with 1/2" dia. "S"
expansion anchors o<span <8' 18"
staggered at spacing 8'<span < 10' 15"
"S" with minimum 21/2" 10'<span < 14' 10"
embedment 14'<span < 16' 9"
AFig.8:Attachment of Ledger Board to Concrete Wall
(See Fig. 12 for spacing and clearances)
Prohibited Ledger Attachments:Attachments to the ends of premanufactured open web joists,to brick veneers, and
to house overhang/bay windows are not allowed when using this Guide (see Figures 9, 10 and 11). In such cases the
decks shall be free-standing (see Free-Standing Decks).
open web
floor joists �I III ,1
I __ IIII
— III t
app ��I deck,, Il oistIIE1k'oist I� \�
e��'-II
4Lpr brick o
ma ,I
I7
I
Fig.9:No attachment Fig. 10:No attachment Fig. 11:No attachment
to open web trusses to brick veneer to house overhang
411/2" (2" at 1/2" thru bolt
and exp bolts)
\.,
o e
_.......„,..
0--p-k o 0
` Silllate
EQ. Spacing "S" beyond
" (where
occurs)
AFig. 12:Ledger Board Fastener Spacing and Clearances
DECK DESIGN GUIDE • 9
MIIlMI.l.l.l.m..m.lmm.l..m.lm..mmmmm'mmm----l:------
ledger Board Fasteners
All fasteners shall be spaced per the tables provided with Figures 5,6,7 and 8 and shall be installed per Figure 12.All
fasteners shall be installed with washers and thoroughly tightened.
Thru-bolts:Thru-bolts are those where a hole is drilled all the way through the wood members and a nut and washer
are attached to complete the connection.Thru-bolts shall have a minimum diameter of'h"Lead (pilot) holes for thru-
bolts shall be 17/32" to 9/16" in diameter.Thru-bolts must be equipped with washers at the bolt head as well as the nut.
Expansion(Wedge)Anchors: Use expansion anchors when attaching a ledger board to a concrete wall as shown in
Figure 8. Bolt diameters of the anchors shall be a minimum of 1/2"; in some cases,this may require an anchor size of
5/8':Minimum embedment length shall be 2'h"Expansion anchors must have washers. Expansion anchors must be
installed as required by the manufacturer's instructions.This may include cleaning the holes drilled in the concrete to
ensure they are free of dirt, debris,and moisture. Improper installation of the anchors can result in catastrophic failure
and collapse of the deck.
Adhesive Anchors:Adhesive anchors may be used with a design by a licensed structural engineer. Special inspections
are required for expansion anchors and adhesive anchors.They are performed by third-party inspectors that are hired
by the project owner.The special inspector verifies that the expansion or adhesive fasteners are installed correctly and
submits a report to the owner and the City.
Lag Screws: Lag screws shall have a diameter of 3/8" and shall be hot-dipped galvanized or stainless steel. Lag screws
may be used only when the field conditions match those shown in Figure 5. See Figure 13 for lag screw length and
shank requirements.All lag screws shall be installed with washers.
Lag screws must be hot dipped galvanized or stainless steel only
3/8" dia. 111,1
Ittl
11111111
Screw must penetrate
beyond and board/rim
joist a minimum of 1/2"
11/2" shank Length must extend through
(no threads) existing band board/rim joist ~�
AFig 13:Lag screw requirements
Lag Screw Installation Requirements: Each lag screw shall have lead (pilot) holes drilled as follows: 1) drill a 3/8" diam-
eter hole in the ledger board,2) drill a 3/16" diameter hole into the solid connection material of the existing house. DO
NOT DRILL A 3/8" DIAMETER HOLE INTOTHE SOLID CONNECTION MATERIAL.
The threaded portion of the lag screw shall be inserted into the lead hole by turning. DO NOT DRIVE WITH A HAMMER.
Use soap or a wood-compatible lubricant as required to help facilitate tightening. Each lag screw shall be thoroughly
tightened.
Mark the size of the ledger board and the fastener type, size, and spacing in the spaces below:
Ledger Size: x ,fastened with ,spaced apart.
Transfer your ledger information above into the Typical Deck Plan at the end of this Guide.
10 • DECK DESIGN GUIDE
Freestanding Decks
Decks that are free-standing do not utilize the exterior wall of the Rim joist
existing house to support vertical or lateral loads.
Freestanding decks allow the exterior siding to remain
on the house,so there is less opportunitiy for
water to get into the wall structure.
Freestanding decks may use precast ��
11
footing pads set 12" below the surface
//��
of the ground on firm, undisturbed �, �� Joist
native soil. Rim , 111 overhang
joist i:
Freestanding decks require an addition Joist
al beam, posts and footings, instead of Grade '
a ledger board attached to the house. \. ��i /
AFig. 14:Freestanding deck
Lateral Support
Decks more than 30 inches above grade must resist lateral forces (wind and earthquake)with diagonal cross brac-
ing as shown in Figure 15. Bracing shall be located between posts parallel to beams and bolted with a 3/8" diameter
through-bolt at each end to the posts as shown. Diagonal bracing shall also be located perpendicular to beams. Bracing
is required in every other bay between posts for decks with joist spans up to 8 feet, and in every bay for decks with joist
spans greater than 8 feet. If the deck is free-standing,diagonal bracing must be provided on all the posts and in both
directions.
J L t_ 1LILL
111 ■ ■ 1111 ■ ■■ 11 ■ ■ ■ ■
• 1•F • • —•
(1)3/8"dia. through bolt • •
at each connection 2X6 cross brace
• •
� X
f0
O
i
• • •
Solid block at intersection of wood Bracing required every bay for deck with joist spans>8'
braces with (1)3/8"dia. through bolt(typ) Bracing required alternate bays with joist spans_<8'
A Fig.15:Diagonal bracing
DECK DESIGN GUIDE • 11
Framing Connections
Mechanical fasteners may be
Joist Hangers: Joist hang- installed in lieu of toe-nails
ers (see Fig. 16) shall have a (3)8d toe '
minimum capacity of 1,000 nailed
pounds.Joist hangers used �— Joists
shall be manufactured for �'', 'their intended lumber size. iJoist-to-Beam Connection: loko
Each joist shall be attached Beam
to the beam as shown in
Fig. 16 or 17.
A Fig.16:Typical joist hangers A Fig.17:Joist-to-beam detail
Secure decking to top Rim Joists:Attach a continuous rim joist
or rim joist with#10X3" min. to the ends of joists as shown in Figure
wood screw at 6" O.C. 18. Note that the rim joists are required
Joists
at both ends of joists infree-standing
decks. Minimum rim joist dimensions
• shall be equal to the dimensions of
the joist.
Built-up Beams: Built-up beams shall be
Attach rim joist to end of each assembled in accordance with Figure 19.
0 •
' joist with (5)#10X3" min. The nailing pattern shall be staggered
Iwood screws as shown.
V Rim joist Post-To-Beam Connection:The post-
to-beam to-beam connection shall be made
with premanufactured mechanical
connectors as shown in Figure 20.
AFig. 18:Rim joist connection Post-to-beam connections may also be
10d nail or#10 (2)fasteners, accomplished using a minimum 6x6
each end post notched for a 4x beam as shown in
wood screw, typ \ Figure 21.All thru-bolts shall have wash-
ers at the bolt head and nut.
Ile
typ. typ.
A Fig. 19:Built-up-beam (2) 1/2" dia. through
2" min.----6; -111111. bolt and washers
(2) 2X beam
Post to beam or 4X beam
connector (2) 2X beam---=I1
'1 or 4X beam -�;�;�
min.
i
11/2" i-r1
4X4 min. 6X6 min. Notch post to
accommodate beam
AFig.20-Post-to-beam connection A Fig.21 -Post-to-beam connection
12 • DECK DESIGN GUIDE
Footings
See Table 1 for footing size and footing thickness
and Figure 22 for post attachment requirements.
The bottom of footings must extend 18 inches
below grade and must bear on solid, native soil.
Bearing conditions must be verified in the field Simpson PB anchor
during the footing inspection, prior to placement
of concrete. Footings closer than 3'-0" to the exist- �Or equivalent
ing exterior house wall must bear at the same pre-manufactured
elevation as the existing wall footing. Do not cast-in-place
construct footings over utility lines or enclosed ril post anchor
meters.Call 1-800-332-2344 before you dig.
a ,1
•
Post Anchors: Premanufactured post anchors shall 6" min •
If ° 4
be capable of supporting a minimum of 3,000 ��1— • d II
i i 1 11
pounds.Where diagonal bracing is required by III— III=1 • e .4. 11-III=111� ..'•a 111
Figure 15,the post anchors must be rated for hori- :111=111=111=111 • • ° 111=-111=-111=-111
zontal (seismic)forces. =111=111=111==1 a as • . . 11IIIIIIIII—
AFig.22:Typical footing detail
Guardrails
Decks and stairways more than 30 inches above the adjacent grade must have guardrails.The guardrail must be de-
signed to withstand a concentrated load of 200 pounds, in any direction anywhere along its length, and the infill area
must withstand a load of 50 pounds per square foot area.
Guardrails using composite wood, plastic, or other pre-manufactured systems must be designed by a structural engi-
neer licensed in the state of Oregon.
4X4 post, typical, 2X2 picket, typical
do not notch 6-4'-0" max spacing—A
2X6 or 5/4 board rail cap
- - — -J - - _ _ ITIT2X4attoP
c
E
o
in ' Zi
---.—C = = F _ 1 _ _ _ _ —
7141) • O
�I •
See guard post _Openings shall not Attach pickets at top and
attachment details allow the passage bottom with (2)#8 screws or
of a 4" dia. sphere (2) 8d spiral shank nails each
AFig.23:Typical guardrail detail
DECK DESIGN GUIDE • 13
2X6 top railing connect to -4-
o ; u � 2X2 picket at 51/2" O.C. max.
post with (2)#10X3" screws '_\ attach pickets at top and bottom
(may be flat or vertical) I with (2) #8 wood screws or
(2) spiral shank nails each
2X4 bottom railing connect to " �-- 4X4 post
post with (2) #10X3" screws A
Decking —. r���
.--- See guard post
attachment options
Figs. 25 - 32
Deck framing
A Fig.24:Guardrail railing and picket detail
Guardrail Post Attachment
Here are five options for guardrail post attachment;you may use one of these,or you may submit a different design for
review and approval. Guardrail posts shall be spaced per Figure 23 and attached per Figures 25 through 32.
Note: 2x8 minimum joists are required for Figures 25, 26,27,30, and 31,and minimum 2x10 joists for Figures 28 and 29.
4X4 posts (pickets and
rails not shown for clarity)
Simpson HD2A or equal holdown
with (2) 5/8" dia. galvanized through
bolts with washers at far side
A
Decking—. r, 'ei '/ JJA Op.
�1'rT7t'_-
11/2" min. P ��� �(2) 5/8" dia. galvanized through
14I bolts with washers
irk
►a���Vii"
2X8 deck 2X8 rim joist with
joints (3) 16d nails at each joist
AFig.25:Guardrail attachment option 1-Deck joists perpendicular,post on outside,manufactured connectors
14 • DECK DESIGN GUIDE
4X4 posts (pickets and____
11
rails not shown for clarity)
Simpson HD2A or equal holdown
with (2) 5/8" dia. galvanized
through bolts with washers
Decking „�� p. A �,,,�� at far side
lir'r
1 i/2"- LWA% MI i►i (2) 5/8" dia. galvanized
G'T7zi �A_/through bolts with washers
2X8 min. 2X8 min rim joist with
deck joists (3) #10x3" stainless steel
screws at each joist
AFig.26:Guardrail attachment option 2-Deck joists perpendicular,rim joist on outside,manufactured connectors
4X4 posts (pickets and rails_� Simpson HD2A or equal holdown
not shown for clarity) with (2) 5/8" dia. galvanized
through bolts with
Decking washers at far side
(2) 5/8" dia. galvanized
r A ,,,� T�` through bolts with washers
Al ,
111111.12X8 joist
ARL 0 0 Ati ,
111 2X blocking with Simpson A34
2X8 min. framing angle each side at
deck joists each end (4 total)
AFig.27:Guardrail attachment option 3-Deck joists parallel,post on outside,manufactured connectors
DECK DESIGN GUIDE • 15
2X6 top railing connect ^ f 2X2 picket at 51/2" O.C. max.
to post with (2) #10X3" ilirr attach pickets at top and
screws (may be flat bottom with (2) #8 wood screws
or vertical) or (2) spiral shank nails each
2X4 bottom railing Er
connect to post with
(2) #10X3" wood screws
11114X4 ost
4" max
1" min. 'iii
A . p A g••
2X10 min-; `t
L6X3X1/4"X0'-9" steel angle/ Jr I (2) 1/2" dia. galvanized through
with (2) 3/4" dia. through bolts j bolts with oversized washers
with (2) vertical short slot holes 11/4" (11/2" dia. min.)
AFig.28:Guardrail attachment option 4-Deck joists perpendicular,post on outside,custom-fabricated connectors
2X10 joist or 2X10 blocking
with Simpson A34 framing
angle at each side at each
end (4 total) 4X4 post
ZENNIMINIMMINII /
(2) 3/4" dia. through bolts .� 2X10 rim joist
L6X3X1/4"X0'-9" steel angle
with (2) 3/4" dia. through bolts
with (2) vertical short slot holes
SECTION A-A
AFig.29:Guardrail attachment section for option 4 '
16 • DECK DESIGN GUIDE
I,
16" Max.
/
Detail A
/HD2AHDG
,a��`il parallel layout
/
/ X Iti
I 4x4 (min) guardrail post
I 7 i
g 2x8 (min) I
blocking 1 '
\II______i_ 4=4}
/2x8 (min)7, ; deck joists
i / �i
Detail Bim` __-_"-"_''
HD2AHDG
perpendicular
layout \be -
2x8
below
(min)
Rim joist
AFigure 30:Guardrail attachment option 5 plan view
(2) HD2AHDG or equal
4X4 post, min. (typ) holdown one this side,
one opposite side of blocking
Decking
HD2AHDG (typ)
holddown Decking (typ)
or equal / 4X4 post,
&Ma r////RUM,' AI FA min. (typ) IL_1 _ 21/2"
�IY. 1
I-
...,„.
iii 1 1 vfi�i�ll
2X8 min.
blocking
5/8"dia. galvanized machine 5/8"dia. galvanized machine
bolts or all thread rods with bolts or all thread rods with
DETAIL A nuts and washers. DETAIL B nuts and washers.
AFig.31:Guardrail attachment option 5 parallel layout A Fig.32:Guardrail attachment option 5
perpendicular layout
DECK DESIGN GUIDE • 17
Stairs
Stairways, stringers, handrails and
guardrails shall meet the require- 9" min. tread width Risers may be open but
ments shown in Figures 33 through shall not deviate shall not allow the passage
36.All stringers shall be minimum
2x12.A level landing minimum 3 from one another
\of a 4" sphere
feet by 3 feet is required at the top by more than 3/8" ........
(usually this is the deck) and at the li
bottom of the stairway (usually a '�,
concrete pad, or the ground).
Note:This stair detail is for a three- •
Risers: 1X material min.
• ■I
foot wide maximum stairway with 8" max. riser height.
minimum 2x tread material. Plastic shall not deviate ` ���
or composite decking products may /4" to 11/2" nosing
be used for stair treads; however, from one another shall not deviate
they may require additional stair by more than 3/8" from one another
stringers for bracing. Check with the by more than 3/8"
manufacturer's requirements.
See Brochure#8 for additional
stair information. A Fig.33:Tread and riser detail
Attach 2X tread material to stringers or cleats with (2) #8 screws or (2) 8d nails
per board at each stringer or cleat
2X tread material Stringer
ii
.—........___________-----v3,
i i 2X4 cleat each side
full depth of tread:
Attach with (4)10d
• •
Stringers nails or#8 • •
wood screws
• •
•
•
rdir
• •
• •
• •
• •
if 5" min.
• •
• •
Max. span = 8'-0" with (2) stringers / Max. span = 15'-6"
Max. span = 10'-3" with (3) stringers
Cut Strinaer Solid Strinaer
AFig.34:Stair stringers and tread connections
18 • DECK DESIGN GUIDE
5'-0" max.
between posts
Stair guardrail required
for stairs with a total rise
of 30" or more. See typical
guardrail details
for more information It.....:
V 14411/0
Stair guardrail_/�height 34" min.
measured from
nosing of tread
,z Triangular opening shall
not permit the passage
of a 6" dia. sphere
A Fig.35:Stair guard requirements Sloped hanger
g wirm,a IIC or LS50 or approved
, equal each side
Band board or rAmirramoso
outside joist rivilA&rum
AFig.36:Stair stringer connection detail
Stair Handrails
Stairs with four or more risers must have a handrail on
at least one side. Handrails shall be graspable and shall
be of decay-resistant and/or corrosion-resistant material.
See Figure 37.The hand grip portion, if circular, shall be 31/2" max.
between 11/4" and 2" in cross section. Shapes other than
circular shall have a perimeter dimension between 4" and 11/2" min. Handrail
not greater than 6'/a" with a maximum cross sectional
/
dimension of 21/47All shapes must have a smooth surface
with no sharp corners. Handrails shall run continuously
•
from a point directly above the lowest riser to a point di- 111110.--- 11rectly above the highest riser and shall return to the guard /-. Corrosion
at each end. See Figure 38. Handrails may be interrupted resistant
at guardrail posts only at a turn in the stair.
handrail
hardware
AFig.37:Handrail requirements
DECK DESIGN GUIDE • 19
3'-0" n. from
deck misurface to
top of guardrail
*\Handrail shall return
at each end
4X4 post, typical
do not notch, Handrail height 34" - 38"
embedded ifrom nosing of tread
concrete 36" max. span _
between stringers w,
I• �__12"X12"X24" ••1:
. . , footing
If•
• 4
AFig.38:Miscellaneous stair requirements
Framing at a Chimney or Bay Window
Decks abutting a chimney or bay window shall be framed in accordance with Figure 39. Headers with a span length
greater than 6'-0" require a calculation.
,/ Decking may
1 , / ( , , , , extend 6" max
6'-O" max / Ledger
f1 t board )1 1
Chimney or bay o �� L
Double joist._-. �/ / / // / j / � 1
each side L.. -. Double
r i r 1 r 1 header (2) 1/2" dia
through bolt
Double joist or lag screws
hanger typical at ledger
Plan Section
AFig.39:Requirements for framing at chimney or bay window
20 • DECK DESIGN GUIDE
DECK FRAMING PLAN
2X Decking attach— Simpson LUS26
Fi?'
Stairs per per general notes min. hanger or Ledger connection
Figs. 33 - 38 approved equal choose from
Fig. 5, 6, 7, or 8
/ ////////////////////// ' \
2X ledger board
• "A"joists 12x at o.c.)
(i) a a II
I
____1111
9 Il "B"beam x
/ I "C"post1____x I
\A
"D"footing L_w x W x L I
_ or
O I— I /1_
a � NI
ID m Cl) I_ _J dia. deep'
'� ——J concrete min. strength:
o I a 2,500 psi
Post spacing or beam span
-'I
I / es
(r)ig. Ft In'
Fig. 1 or 2
Fig. Guardrail post connection
Choose from
cg
Notes: Beam span Fig. 25, 26, 27,
1. See general notes for additional information 28, 29 or 30
z 2. See Figure 15 for diagonal bracing requirements
C,
0 3. See Figures 20,21 for post to beam connection and figure 18 for rim joist connection
^' 4. See Figure 23 for typical guardrail elevation
N
Helpful Information Scheduling an inspection
Bureau of Development Services • Call 503-823-7000, the BDS 24 hour inspection
City of Portland, Oregon request line
1900 SW 4th Avenue, Portland, OR 97201 • Enter your IVR or permit number
www.portlandoregon.gov/bds • Enter the three-digit inspection code for the
General Office Hours: type of inspection you are requesting
Monday through Friday,8:00 am to 5:00 pm • Enter a phone number where you can be
BDS main number: 503 823-7300 reached during weekdays and if you want the
Permit Information is available at the following location: inspection in the morning or afternoon
Development Services Center(First Floor) • There must be an adult over age 18 to allow the
For Hours Call 503-823-7310 I Select option 1 inspector entry
Permitting Services (Second Floor)
For Hours Call 503-823-7310 I Select option 4
V To be safe, remember to call before you dig,and have
Important Telephone Numbers your underground utility lines located.
BDS main number 503-823-7300 V Check with PDOT regarding the width of the
right-of-way if you are building in your front yard.
DSC automated information line 503-823-7310
Building code information 503-823-1456 V Depending on your location and the specifications
503-823-7526 of your project, building and/or zoning permits may be
Zoning code information required.
Permit information for electrical, V Some zones have special requirements which could
mechanical, plumbing,sewer
and sign 503-823-7363 affect your outdoor project.
Permitting process and fees 503-823-7357 V If you have any questions or concerns about your
Permit resources and records 503-823-7660 project, check with staff in the DSC about zoning
and building issues.
BDS 24 hour inspection request line
requires IVR number and three digit
type of inspection code 503-823-7000
Residential information for
one and two family dwellings 503-823-7388
Environmental Soils 503-823-7790
PDOT Engineering 503-823-7002
City of PortlandTTY 503-823-6868
Call before you dig 503-246-6699
For more detailed information regarding the bureau's
hours of operation and available services;
Visit our Web site
www.portiandoregon.gov/bds
Note:All information in this brochure is subject to change.
res_deck 03/05/13
22 • DECK DESIGN GUIDE