Decks California - builder - contractor - design - construction
Decks California - builder - contractor - design - construction
| Max. Joist Span | 6'0 | 8'0 | 10'0 | 12'0 | 14'0 | 16'0 | 18'0 | |
| SDS Screw Length | Rim (band) Type | max. fastener on center spacing | ||||||
| All - 3½ | 2x wood | 13 | 10 | 8 | 6 | 5 | 5 | 4 |
|
Connection
Type |
1" Engineered | 12 | 9 | 7 | 6 | 5 | 4 | 4 |
| 1 1/8" Engineered | 15 | 11 | 9 | 7 | 6 | 5 | 5 | |
| All ¼ sds screw ½ ply | 1 1/4" Engineered | 15 | 11 | 9 | 7 | 6 | 5 | 5 |
Designing decks for our location
We live in the beautiful wine country of Northern California. When we design decks for our area these are the building practices we follow. Always refer to your local building codes or a structural engineer.
Fastener spacing table for bolting decks ledgers
See table above for typical connections and below for a simpson SDS screw option.
We prefer not to attach our decks but when there is no choice for an additional beam at the house
we use the above schedule for lags with a 2x ledger thru shear ply or T1-11 typically to a solid rim (band) joist with a 1/2" mositure space between the ledger and the rim, flashed.
Positive connection for lateral loads
Decks building codes - Ledger Attachment - IRC & IBC
Where supported by attachment to an exterior wall, decks shall be positively anchored to the primary structure and designed for both vertical and lateral loads as applicable. Such attachment shall not be accomplished by the use of toenails or nails subject to withdrawal
IRC R502.2.2.1.1
The lag screws or bolts shall be placed 2" from the bottom or top of the deck ledgers and between 2"-5" in from the ends.The lag screws or bolts shall be staggered from the top to the bottom along the horizontal run of the deck ledger.
IRC R502.2.2.2.
Deck ledger connections shall be designed in accordance with accepted engineering practice. Girders supporting deck joists shall not be supported on deck ledgers or band joists. Deck ledgers shall not be supported on stone or masonry veneer.
The ledger must be securely fastened to the rim joist or blocking within the residence floor joist system. Deck ledgers in our earthquake zone need to be positively attached to the residence framing at 8' o.c. with connectors not subject to withdrawal, typically LTT19's. See below for the DTT2Z option - Simpson Strong Tie.
Connectors and Fasteners For Use With Pressure-Treated Wood
Hot-dipped galvanized or stainless steel should be used when in contact with treated woods
Pressure Preservative-Treated Wood and Fire-Retardant Treated Wood can be caustic to zinc-coated (or galvanized) steel and cause the metal to deteriorate. Connectors and fasteners utilized with these wood products must be of the correct type.
All metal connectors in contact with pressure-treated wood should be either hot-dipped galvanized or stainless steel.
Fasteners of comparable materials should be used to install metal connectors. Fasteners must be hot-dipped zinc coated galvanized, stainless steel, silicon bronze or copper. Electrogalvanized nails, screws or staples shall not be used.
A typical Ltt19z exterior connection.
In layout line up the deck joist with the homes joisting.
Interior connection to an Ijoist
Block and cinch the nails for the Ltt19z attachment
Ltt with flashing for siding connection
There is a self-adhesive flashing membrane behind the ledger
Decks building codes
Lateral load connection - IRC
Hold-down tension devices shall be provided in not less than two locations per deck, and each device shall have an allowable stress capacity of not less than 1500 lbs.
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Serving North Marin & West Sonoma Counties in the San Francisco North Bay area of Northern California
Always inspect the rim joist, your deck ledger is only as strong as what it's connected to. The rim needs to be solid with no rot and constructed using proper building practices such as glued and nailed floor ply, plate, sill and joist connections.
Drill a 1/2 hole in the ledger and a 5/16 pilot in the rim.
Don't drive the lags in with a hammer then thread them it may damage the rim for withdrawl. Especially with the manufactured band joists.
The Bolts are required to be 1/2 dia. with pilot holes of 17/32 to 9/16 and they need washers at the nut and head.
| Max. Joist Span | 6'0 | 8'0 | 10'0 | 12'0 | 14'0 | 16'0 | 18'0 | |
| Connection Type | Rim (band) Type | max. fastener on center spacing | ||||||
| ½ Lag ½ ply | 2x wood | 30 | 23 | 18 | 15 | 13 | 11 | 10 |
| ½ Bolt ½ ply | 2x wood | 36 | 36 | 34 | 29 | 24 | 21 | 19 |
| ½ Lag ½ ply ½ space | 2x wood | 36 | 36 | 29 | 24 | 21 | 18 | 16 |
| All | 1" Engineered | 24 | 18 | 14 | 12 | 10 | 9 | 8 |
| All | 1 1/8" Engineered | 28 | 21 | 16 | 14 | 12 | 10 | 9 |
EWP :: Engineered wood product (OSB, LVL, SCL) MPCWT :: Metal plate Connected Wood Truss
The loading condition is 40 psf live and 10 psf dead
The Moderate zone in Sonoma County California, the higher mountain regions may differ.
SDS Screw Spacing
Deck ledgers shall be minimum 2x8 pressure-preservative-treated No. 2 grade lumber
Lag & Bolt Spacing
Simpson Strong-Tie Strong-Drive Screw
Stainless or Hot dipped Galvanized
Don't under estimate the importance of the flashing. If moisture is trapped at the ledger the sheathing ply and rim (band) joist will prematurally decay and create a deck failure so it's as important as the connection.
Decks building tutorials and design tables
The frequently asked questions on how to build decks for Northern California
Always refer to your local building codes or a structural engineer this is how we build our decks
Deck footing & pier sizing for California
Deck connections for California's #4 earthquake zone
California decks built up and solid beam size tables and post size table.
Tables for the minimum joist spans in California's moderate climate regions
How we build a closed in riser stair for decks with a skirt for solid railings
Deck stair total rise table with calculations for riser heights and number of treads
Website Design by Owner
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This page last modified on Thursday, February 10, 2011
Attached Decks greater than 6' wide over openings
Decks attached to the house with doors, windows or openings below must check to verify the existing headers over those openings can support the additional added load.