Deck Connections
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Bolting Schedule for Deck Bands |
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| Joist Span |
6' |
7' |
8' |
9' |
10' |
11' |
12' |
13' |
14' |
15' |
16' |
| Bolt Size |
1/2" |
1/2" |
1/2" |
1/2" |
1/2" |
1/2" |
1/2" |
1/2" |
1/2" |
1/2" |
1/2" |
|
5/8" |
5/8" |
5/8" |
5/8" |
5/8" |
3/4" |
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| Bolt Spacing |
24" |
24" |
18" |
18" |
16" |
12" |
12" |
12" |
12" |
12" |
12" |
|
24" |
21" |
18" |
18" |
16" |
16" |
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| 16d Nail Spacing |
9" |
8" |
7" |
6" |
5" |
5" |
4" |
4" |
4" |
3" |
3" |
| Note : This table assumes a deck design load of 50 psf (40 psf live load, 10 psf dead load), and Southern Pine 2-by dimension lumber. As an example, for a deck spanning 8 feet, you can use 1/2 -inch bolts on 18- inch centers or 5/8 -inch bolts on 24-inch centers. | |||||||||||
Interior
Exterior
We also use Ltt19's from simpson strong tie and install them at every 8' on center min.
These used with a 3/4 thru bolt creates a positive connection to the building.
For i-joists we nail 6' of 2x4 with 10ds & cinched to the side & attach the Ltt19 to those.
(click for larger images)
For joists that run parallel to the band we block over two joists, as in the example of the I-joist below, and as the typical detail we use on our plans.
future detail
Here on the left is the worse case scenerio, i-joists & plumbing. We still block over 2 joists as per the detail (right) but in this case we used a 2x12 flat & 2x4 upright then nailed the ltt19 to the 2x4. Solid block over to the band.
Blocked
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1/2" x 3 1/2" Lag Screw
Ledger Connections
1/2" x 4" Lag Screw with 15/32 Ply Sheathing
1/2" Bolt with 15/32 Ply Sheathing
1/2" Bolt with 15/32 Ply Sheathing and 1/2" drainage
Deck Loading
Decks Not Often Fully Loaded
Code design loads require residential decks to be able to support a 40-psf live load plus a 10-psf dead load. Assuming a 12x18-foot deck, 40 psf would be roughly equivalent to a gathering of 58 people, based on an average weight of 150 pounds per person. In reality, however, that many people are unlikely to gather at one time on a 12x18-foot deck during its entire service life.
Loads Not Uniform
Fastener schedules assume that the deck will be uniformly loaded, so that approximately half of the load will need to be supported by the ledger. But large groups of people don't normally sit right next to the house. Instead, more people tend to gather near the outer edges of the deck, so that live loads are typically greater on the outer supports compared with the house side
We connect our decks to your home with a ledger, this is bolted & lag screwed rather than just nailed as is a common practice. We believe that the codes for decks will be changed within the next few years to follow this practice.
We also use zmax joist hangers of the LUS type which have additional nailing for 10d angled into the ledger. All of our hardware is up to date with the new ADZA pressure treatment.
See our Petaluma Deck built 5 years ago for more on connections and
full step by step with project photos on our Alter Eagle Site.
* These spacings have been reduced from the allowable value determined by testing in consideration of the ledger's bonding strength between bolts.