Decks California - builder - contractor - design - construction

Deck joist spans

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.

Alter Eagle is a professional licensed and insured deck building contractor

Click for a larger images
You can use your mousewheel to scroll though all of the pictures

The below deck span table is from the American Wood Councils prescriptive deck design guide based on the structural studies on decks at Virginia Tech and Washington State. I prefer to use this span table when designing decks.

40 psf Live, 10 psf Dead
No.2 or better	O/C	2x6	2x8	2x10	2x12
D.Fir / Larch	12	10-9	14-2	18-0	20-11
	16	9-9	12-9	15-7	18-1
	19.2	9-2	11-8	14-3	16-6
	24	8-3	10-5	12-9	14-9
Hem-Fir	12	10-0	13-2	16-10	20-4
	16	9-1	12-0	15-2	17-7
	19.2	8-7	11-3	13-10	16-1
	24	7-11	10-2	12-5	14-4
S.Pine	12	10-9	14-2	18-0	21-9
	16	9-9	12-10	16-1	18-10
	19.2	9-2	12-1	14-8	17-2
	24	8-6	11-0	13-1	15-5
UBC-1997	Maximum Allowable Span Feet - Inches

Joist Span Table

The span table used in our area for 2011 is the UBC 1997 code (left) for the minimum size of joists for decks.

These joist spans tables don't take into account the wet conditions.

The IRC deck joist span table

Serving North Marin & West Sonoma Counties in the San Francisco North Bay area of Northern California

This span table takes into account the joists are being used in exterior applications and how the wet conditions can reduce the strength of lumber so the maximum spans allowed are less than the above table that we currently use.

The joist size in the above table

The spans in this table aren't clear spans like usual they are from the centerline of bearing on one end of the joist to the center of bearing on the other end. They don't include the cantilever (overhang) of the joist.

40 psf Live, 10 psf Dead
No.2 or better	O/C	2x8	2x10	2x12	2x8	2x10	2x12
D.Fir / Larch Hem-Fir / *SPF	12	12-6	15-8	18-0	9-5	13-7	18-0
	16	11-1	13-7	15-9	9-5	13-7	15-9
	24	9-1	11-1	12-10	9-1	11-1	12-10
S.Pine	12	13-8	17-5	18-0	10-9	15-6	18-0
	16	12-5	15-10	18-0	10-9	15-6	18-0
	24	10-2	13-1	15-5	10-2	13-1	15-5
Redwood Western Cedars	12	11-8	14-11	17-5	8-6	12-3	16-5
	16	10-7	13-0	15-1	8-6	12-3	15-1
	24	8-8	10-7	12-4	8-6	10-7	12-4
IRC-2011	Without Overhangs				With Overhangs

*SPF - They have spruce-pine-fir in their table in with the same species as Doug-fir and Hemlock, personally I wouldn't ever use spruce for deck framing. As far as Redwood framing with the pith content in 2nd growth I'd only use #1 heartwood not #2 as in the table.

The cantilever (overhang) can be 1/4 the joist length, but again I would keep that to 2'-6 max. for 2x8. Deck loading has a tendency for the people to gather at the railing. So I typically don't go beyond that.

How to build deck stairs

Stair height calculation table

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 joist min. span tables

Deck connection tables

Deck beam and post sizes

Deck footing and pier sizes

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