BLD2021-0002+Calculations+1.2.2021_1.13.53_PM+1970597RECEIVED
Jan 04 2021 BLD2021-0002
CITY OF EDMONDS
DEVELOPMENT SERVICES
DEPARTMENT
Calculations
All framing material for the deck will be pressure treated Hem -Fir wood. The posts will be 4x4s,
the deck beams will be 4x12s, the stair landing beams will be 4x8s, and the ledgers, joists, and rim will
be 2x10s according to the Washington state SBCC joist span table R507.5 and beam span table R507.6.
Siding will be removed and a 2x10 ledger board will be bolted to the house and properly flashed. The
joists will be nailed into exterior grade metal hangers set on 16" centers on the ledger board. Material
for the decking will be 1x6 composite.
Deck joist span calculations were taken from the Washington state SBCC joist span table R507.5.
With joist spacing at 16" on center, the allowable deck joist span with cantilevers for 2x10 hem -fir is 11'-
6". The deck joist spans in this deck design do not exceed 10'-0" and the cantilevers do not exceed 2'-4".
Deck beam span calculations were taken from the Washington state SBCC joist span table
R507.6. With joist spans at 10'-0" or less, the allowable deck beam spans for 4x12 hem -fir is 10'-0". The
deck beam spans in this deck design do not exceed 10'-0" and the cantilevers do not exceed 2'-0".
Stair landing beam span calculations were also taken from the Washington state SBCC joist span
table R507.6. With stair landing joist spans at 7'-0" or less, the allowable deck beam spans for 48 hem -
fir is 7'-9". The deck beam spans in this deck design do not exceed 3'-0" and the cantilevers do not
exceed 0'-6".
beams.
The posts are all 4x4 and do not exceed 7'-0" in height from the footings to bottom of the
Placement of lag screws in deck ledgers and band joists shall be per the Washington state SBCC
table R507.2 which shows allowable on -center spacing of fasteners at 13" for %" diameter lag screws
with %" maximum sheathing at less than 10' joist spans. All fasteners shall be hot -dipped galvanized
steel.