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Report (39) 4 i ® ate sit." ° •ks � � s - s - l �' )eck eDesign Guide 'T2 ) oo , 9-5 - - Jos- ) Z 10c.i s`t"; h _ :fir E One and Two Family Residential Dwellings The Bureau of Development Services (BDS) is providing this information to help you design your deck, obtain a building permit CONTENTS and pass inspections. The standards and details in this Guide will Do I Need A Permit? f .:A, help you determine how large the footings, beams, joists, posts, and z , ,' ledgers need to be; how to build lateral bracing, stairs, and railings; What Plans Do I Need? 2 '..;: and how to fasten all of the pieces together. This Guide does not ... take into account conditions which may affect your deck design such General Notes 3 + ` as drainage conditions, slope conditions, or decks supporting loads Footings,Beams,Joists,and Posts 4 C; d in excess of the standard uniform loads. Depending on your specific W 0 situation, you may need to hire a licensed architect or structural The Ledger Board 7 4/1 CTI engineer prior to approval.' ' o You may include all, or part of the pre-approved Freestanding Decks 11 p pproved design standards and Z details in this guide with your building permit plans for decks that are: Lateral Support of Decks 11 W +a - For one- and two-family dwellings Framing Connections 12 CI- o - Single-span Co Q OFFICE COPY Footings 13 ..f `- All on one level Guardrails 13 W - Not supporting a hot tub or spa Stairs 18 W • • Not attached to house overhangs, bay windows, brick, stone or p c) concrete block Chimneys/Bay Windows 20 C ^ •Not more than 10 feet above the ground Deck Framing Plan 21 r� Not bearing on ground with a slope greater than 2 feet horizontal co for every 1 foot vertical Helpful Information 22 Q M W p CC "' Guard • I I gard City of I I f m o Oil Le Approved Plans der board !TIi0:t i i ) *, • I ,r,' lil ,. ,/ 1 ill Ledger board Q Footing /' attachment -a cif 1 .. Grade Q I\/I .% Joist Joist 11 . CL C ' Post to beam a,�. \N." i connection C Built-up beam ° v1 o j• Cf0/(- 13�(13 8'11°� °��` j / /0,57`1, eit/ 'CAA/ h 1 r, `� I ��r 7j0,rI, a 72Lq I. 50 2_09-- 9/2_8 DECK DESIGN GUIDE • 1 lan,51- iO1L. OOJ4 Optional overhang i N N N RB q Beam splices at interior post 4C locations only D I - 6" min 2'-0" max. Beam� span� p Beam s an 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: --77 f/ A. Joist Size: L., x____ , spaced Ly apart. (Al c ) B. Beam Size: Y x / 1. . ( Z— 2.*/2 9 C. Post Size: x �. '/ f , spaced t>' 0 apart. /1 D. Footing Size: /0 x do p.,, x Transfer your footings, beams, joists, and posts information above into the Deck Framing Plan at the end of this Guide REVISION DECK DESIGN GUIDE • 5 ., . he 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 existing 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 (before it is II installed) and ending on the First layer flashing behind building outer face of the exterior wall Exterior wall sheathing • and ledger board, and over siding siding or foundation below the (15/32" max sheathing) Second layer"Z" flashing over top bottom of the ledger board. peel- Existing wall and down face of ledger board anSed-stick sbh ng is idealus e '—.._-. 11C....._ and stick flashing is for the first layer. Pre-formed //A%.A Decking over Z-shaped metal flashing is ideal Existing 2X 0 �i deck joist for the outer, second layer of rim (band) I I flashing. It is installed after 2X ledger, same size the ledger board and before 2X floor joists n \ as deck joist the joists, starting behind and 1� -41 ` Joist hanger LUS26 above the bottom edge of g the building paper and siding, I (or equal) min. continuing down vertically to Existing wall framing I ,, 1/2" lag screws or the top of the ledger board, or concrete wall I 1/4"X41/2" Simpson SDS screws bending horizontally to the (shown dashed (ore equal) staggered from topto bottom outer face of the ledger board, ) q ) ggand bending again vertically and spaced at spacing "S" down the face of the ledger board at least 1/2". AFig. 5:Attachment of Ledger Board to Band Board with Lag or Wood Screws (See Fig. 12 for spacing and clearances) Spacing"S" Joist Span Vh"dia.lag screws*! Simpson SDS 1/4"X 4 1/i" ) 0 < span < 8' 23" 14 8' < span < 10' 18" 12" 10' < span < 14' 13" 8" 14' < span < 16' 11" 6" *The tip of lag screw shall fully extend beyond inside face of rim joist!From table R502.2.2.1 of 2011 ORSC. Man .cture' ' ood Joists(MWJs): If the existing house floor joists are MWJs, and not V/ solid-saw I. ber, you will need to submit a ledger attachment detail that is approved by the M J • anufacturer or a licensed engineer. Examples of MJWs are TJI, GPI and A Fig. 4:MWJ profile LPI. S- Figure a. Older homes constructed with MWJs may have a plywood band board, whi - some newer homes may have 1 1/4-inch manufactured wood rim joists. DECK DESIGN GUIDE • 7 Concrete wall Decking over /deck joist ft 2" min. I _ Joist Span Spacing 2X ledger with 1/2" dia. 'IS„ 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 IIi NI II9 �� lill deck i1 deck `��to,Iiii L � -111 Il 'oist MrI�I��l 'oist riv., brick o i �� ma , 4 li Fig. 9:No attachment Fig. 10:No attachment Fig. 11:No attachment to open web trusses to brick veneer to house overhang 2"to 5" max from end /41/ 0 0 2" Staggered fasteners�� y` — — —o o top to 2"/ bottom di/Spacing "S" dl, AFig. 12:Ledger Board Fastener Spacing and Clearances DECK DESIGN GUIDE • 9 . ' reestanding Decks Decks that a - fre: standing do not utilize the exterior wall of the Rim joist existing house o support vertical or lateral loads. Freestanding dT c - allow the exterior siding to remain on the house,/so there is less opportunity for water to get into the wall structure. -- .10.-- � ' ��/ .� Freestanding decks may use precast % footing pads set 12" below the surface /� r of the ground on firm, undisturbed , �I I Joist native soil. Rim // overhang joist 0 Freestanding decks require an additionalJoisSlill beam, posts and footings, instead of a Grade `_/11111)i,ledger board attached to the house. `_/ l / `, 40 .Fig. 14:Freestanding deck Lateral Support Decks more than 30 inches above grade must resist lateral forces (wind and earthquake) with diagonal cross bracing 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 L ■ ■ ■ ■ lir ■ ■ ■ ■ ■r. . . . . . . • . • : ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ • _i.F. • rinium.r.rw • • • • . „ „ A . • (1)3/8"dia. through bolt • • at each connection 2X6 cross brace 1 1171r • • A N O O • • • 71 _Solid block at intersection of wood Br- • r-•.' -• -,- - .-- _ sans>8' braces with (1)3/8"dia. through bolt(typ) Bracing required alternate bays with joist spans_.8' A Fig.15:Diagonal bracing "�'' J' ..... DECK DESIGN GUIDE • 11 °' ootings 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 during the footing inspection, prior to placement Simpson Pn anchor of concrete. Footings closer than 3'-0" to the .di equivalent existing 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 n, post anchor meters. Call 1-800-332-2344 before you dig. y 'I • a , Post Anchors: Premanufactured post anchors shall 6" min • . I1 4 • I. • • be capable of supporting a minimum of 3,000 . a ;l -,I 1=� pounds. Where diagonal bracing is required by -111111=„ 11 I I—I I—I • a L•.a .• I I=III=III—III— Figure 15, the post anchors must be rated for :111---1 I —III—III • a III—III—III—III: horizontal (seismic) forces. —III-III-III-I ad : o • I 1-III,=III-III- . • 4 A Fig. 22: Typical footing detail Guardrails Decks and stairways more than 30 inches above the adjacent grade must have guardrails. The guardrail must be designed 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 aluminum, composite wood, plastic, or other pre-manufactured systems must be designed by a structural engineer licensed in the state of Oregon. 4X4 post, typical, 2X2 picket, typical do not notch71--4'-0" max spacing 2X6 or 5/4 board rail cap - - - --� - - - - _ — : 2x4att0p _.0 = . = I = =, 2 I li O • ® A O 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 A Fig. 23:'Typical guardrail detail OFFICE COPY DECK DESIGN GUIDE • 13 4X4 posts (pickets and___ rails not shown for clarity) Simpson HD3B or equal holdown with (2) 5/8" dia. galvanized through bolts with washers Decking „�A /,,, , 02 at far side ialffr ti 11/2" "1"FAV (2) 5/8" dia. galvanized r_�r ►ziftM_/through bolts with washers 2X8 min. L 2X8 min. rim joist with deck joists (3)#10x3" stainless steel screws at each joist AFig. 26: Guardrail attachment OPTION 1A -Deck joists perpendicular to guardrail, rim joist on outside, manufactured connectors 4X4 posts (pickets and rails Simpson HD3B 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��„ �� TM::PM through bolts with washers 0 Al 7'11 2X8 min.joist 2X blocking with Simpson A34 2X8 min. framing angle each side at deck joists each end (4 total) AFig. 27: Guardrail attachment for OPTION 1 and 1A -Deck joists parallel to guardrail, post on outside, manufactured connectors DECK DESIGN GUIDE • 15 I y 16"Min. i; DETAIL A (Figure 31) J— DTT2Z deck joist perpendicular to guardrail / II 4x4(min.)guardrail post at 48"o.c.(max.) -------I -- I1 1 � 1 I 1 I I to 2x8(min.) blocking –2x8(min.) r deck joists \---i I- -- . �I II:m,II,,0 urn Li 1 DETAIL B I (Figure 32) DTT2Z deck joist parallel to guardrail 2x8(min.)rim joist---"---- /\___ beam below AFigure 30: Guardrail attachment OPTION 3 plan view Guardrail post Guardrail post Simpson DTT2Z (2)Simpson holdown or equal DTT2Z holdowns Decking or equal(one each 1/2"diameterside of blocking) 1/2"diameter machine orthreaded bolts `A—�`6- machine bolts -- �, or threaded - rod with nuts � m"',n,��, � ��, N rod with nuts ��NIONQui,i�1l,,. and washers , Asa. .��r.. Ai_•I1Ii1r• and washers II:MORI'I Illi:, fill i Rim joist i Deck joist I Blocking I (2x8 min) I (2x8 min) ' IDeck joist(2x8 min) ' 16"Min. I X 1 Detail A Detail B A Fig, 31: Guardrail attachment OPTION 3 A Fig. 32: Guardrail attachment OPTION 3 perpendicular to guardrail parallel to guardrail DECK DESIGN GUIDE • 17 5'-0" max. between posts Stair guardrail required for stairs with a total rise Olg III of " or more. See typical guardrail details for more information v lli I r7 rT Stair guardrail, /.". Ati height 34" min. 4105 IA measured from nosing of tread .ff��I Z. Triangular opening shall not permit the passage of a 6" dia. sphere A Fig. 35: Stair guard requirements Sloped hanger Ir I or LS50 or approved lI equal each side 1 Band board or outside joist MIAIIIIWIra 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 1 '4" and 2" in cross section. Shapes other than circular shall have a perimeter dimension between 4" and 11/2" min--- ---yAz Handrail not greater than 634" with a maximum cross sectional dimension of 23/4". All 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 0.-- 1 • directly above the highest riser and shall return to the Corrosion guard at each end. See Figure 38. Handrails may be resistant interrupted at guardrail posts only at a turn in the stair. handrail hardware AFig. 37:Handrail requirements DECK DESIGN GUIDE • 19 DECK FRAMING PLAN 2X Decking attach— Simpson LUS26 Fig. Ledger connection Stairs per per general notes min. hanger or Figs. 33 - 38 approved equal choose from Fig. 5, 6, 7, or 8 ///////////////////////////////////////////////////// 2X ledger board • "A"joists 2x at o.c. 0 ii "B"beam x co h h 15 I � ) "C"post x ( "D"footing W x W x L _ or �, .,� < I I I dia. deep x I _ I_ _-1 concrete min. strength: 3 o I a 2,500 psi Post spacing or beam span p) ig. / Fi Ft In Fig. Guardrail post connection = g. 1 or 2 3 Choose from o 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