Typically I'll use the ABAz with a 1/2 anchor bolt. Joints in beam layers must fall over posts. The Old Engineer says: I assume that you mean a 6WF12, which has a height of 6”, flange width of 4”, and a weight of 12lb/ft. on-center along both edges. For pressure-preservative-treated southern pine no. Building codes for residential decks only require 40 psf. Beam span and cantilever measurements are taken from the center of the posts, not the face of the posts. The beam table is limited to 10 psf. Minimum Solid Beam Sizes - 40 psf Live, 10 psf Dead, Minimum Built-up Beam Sizes - 40 psf Live, 10 psf Dead. I prefer the adjustable 1" stand-off bases for decks above 30" I also keep my piers a min. Most locations have added it to their deck framing code. Repetitive Member Fb design values are used in design when three or more load sharing members, such as joists, rafters, or studs, are spaced no more than 24" apart and are joined by floor-ing, sheathing … I like to use this provision when sizing beams. when the deck joists are 6 ft. long. Douglas fir is recognized for its superior strength-to-weight ratio and has the highest ratings of any western softwood for extreme fiber stress in bending. If you have to use a built-up I suggest placing a flashing cap or membrane that won't break down and not use the ardox (threaded nail) as prescribed but use sds screws or thru-bolts. Sizing deck beams got a lot easier with the publication of the 2015 International Residential Code. live / snow load. I put the built-up beam span table below but I would very rarely use a built-up beam in an exterior application where they are exposed to the moisture conditions like a deck. Become a member and get instant access to thousands of videos, how-tos, tool reviews, and design features. There are other beam provisions and limitations in the 2015 IRC to take note of: Even if your local code jurisdiction hasn’t adopted the 2015 IRC, most building officials will look favorably on an ICC sanctioned code provision. This allows me to make the beam a little smaller (by dropping, say, from a double 2×10 to a double 2-2×8). Beam span maximums are based on a maximum anticipated live load. Start your subscription today and save up to 52%. Always refer to your local building codes or a structural engineer. code for nailing they will still check, may warp and will shrink at the splices which allows moisture to get trapped with dirt promoting the compromise of the beams over time. Typically I use the ACz post caps (right) for most decks, they handle the loads well and are easier to work with placing the heavy beams. 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, Alter Eagle
Section R507.6 calls for the built-up beams to be fastened together with a minimum of 10d nails spaced 16 in. ft)= beam spacing x post spacing. We offer 6x12 timbers in lengths from 10 feet to 24 feet. Timbers are horizontally stickered and air dried. These values didn’t change in the 2018 version of the IRC. Douglas fir works well with power tools and can be painted or stained as needed. So run the table by your building official for approval before using it. Although the practice is common, there’s no allowance for interpolating beam spans when the joist length you’re dealing with isn’t listed in the table. Beams are permitted to cantilever past the end posts up to one-quarter of the beam span between posts. for heavier loads or hill sides. You can plan for a 8'-3" span for the beam with 10' on both side. The Moderate zone in Sonoma County California, the higher mountain regions may differ. (For more on other aspects of framing an elevated deck, have a look at this guide.). Decks building tutorials and design tables, The frequently asked questions on how to build decks for Northern California
Build a Grade-Level Deck: Install Posts and Rim Beam, Adding Fascia and Other Decorative Elements, Laying Out, Cutting, and Installing the Stringers, Installing Treads, Risers, and Stair Railings, Expert insights on techniques and principles. For example, a double 2×8 beam can span 8-ft.-0 in. When the deck joists are 8 ft. long, the beam can span 7-7. Decks Project Guide. dead load and 40 psf. 6"x12" Full dimension, rough sawn Red Pine (aka Norwegian Pine) timbers are responsibly harvested and milled in northern Minnesota. I'll use the PCz post caps (left) if I have a condition on a slope with possible lateral movement or a heavy load with a large joist over a longer span. Solid blocking over beams should be mandatory for decks. Sign up for eletters today and get the latest how-to from Fine Homebuilding, plus special offers. © 2020 The Taunton Press, Inc. All rights reserved. When building a deck with 7-ft. joists, you know the beam can span somewhere between 7-7 and 8-0, but you don’t know exactly where. Based on the information provided and a 750 psi allowable bending stress for a doug-fir timber, you can plan for a maximum span of 9'-3" for the beams with 6' on one side and 10' on the other. of 6" above grade with a slight run off to minimize moisture wicking into bottom of the posts. With the min. I put the built-up beam span table below but I would very rarely use a built-up beam in an exterior application where they are exposed to the moisture conditions like a deck. Both are adjustable the ABUz post base (left) uses a 5/8 anchor bolt
These are the beam size tables I use from the UBC code I find they still work well, I laid them out so they are easier to read and I found them better than the interior IRC table or the new deck prescriptive. 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.