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I’m designing a new deck; basically 14′ x 25′ – fastened on one 25′ side to a ledger on the house with the other three sides free-standing – Support on the free-side will be 12′ from the house w/ a 24″ o’hang. I’m getting conflicting info from various sources (on-line design sites & local builders) re: joist & beam size. I intend to use 2 x 10 PT pine joists on a doubled 2 x 10 beam – I’m not afraid of ‘overbuilding’ but am being told that 2 x 8 joists w/more support posts is the ay to go? Can anyone give me a little direction based on experience?
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after a series of collapses, the RI code was amended so deck design must be for 60 Lb. / sf. loading...
...i don't know what your code is, but to get 60 lb/sf you have to use 2x8@ 12inches OC
or 2x10 @ 16inch OC....for a 12ft span, even without the code requirement, i would use the 2x10, decks tend to get concentrated loads and you won't like the bounce...
IMHO
*Phillip:I don't know what you mean by "am being told that 2 x 8 joists w/more support posts is the way to go" but I can tell you that 2x8 joists, 16" o.c. with a 12' span will produce a floor with some bounce in it. By "more support posts" are you insinuating a second girder (beam)? Either way, unless you have soft soil, I would stay away from digging any more holes than are necessary to support the weight.A side note: You say "w/ a 24" o'hang". Be aware that a 24" cantilever (overhang), at least by the CABO code, is maximum, so don't be tempted to stretch it a few inches further. Also, the cantilever is another good reason for 2x10s.
*I would think consideration should be given to the decking direction and material thickness before you guys/gals get too revved up and kick out a reccomendation.Phillip, would you add the decking direction, material and thickness to the thread info. Also what is your post/beam span spacing? A little more on the post size and beam attachment would help too.
*Phillip...The 2x10s are the way to go...I would possibly use a more stout beam...go with 3 2x10 or 1x12...depending on your support post spacing...Go to Home Depot and get it all printed out with their deck software...near the stream,ajPS- the decking material is no biggy, I assume you'll use the beautiful Mahaghany 5/4x6 stock thats available at $1.50/ft and fasten from below, so as to have the most beautiful deck in the neighborhood. Jatoba is another beauty and ohhh so dense.
*I agree with Anderson. What is your post span on the beam. To me 2x10 is an overbuild, but the deck problems usually come from improper post footings. A little deflection on a deck to me is no real concern as long as within the code 12'6" here with 40lbs load witch is a standard floor load. Also what # pine are you using makes a big difference! I think we can all agree that most problems are from inadequatefootings on the posts.Mark
*Chisel Head...Most problems!?...Boy if anyone has a problem with building a deck...sell the tools quick!!!!...Then go buy beer, for drinking while one watches others do the work...Can't be anything easier or more written about and sold at the Depots of the World...near the stream, wading till noon...aj
*Jack!!! To mutch time here... Its going to your head! Decks are to easiest to build, yes. But for a do-it yourselfer the easiest to screwup. "Wow this digging is tough,Ahh 1' deep is enough" Seen all too many decks falling to china by way of bad or no footings. Out to lunch...soooon!
*CH...They're all perfect around here except for the totally checked up PT....Lunch...I'll take a BLT and clam chowder soup...and a Sam Adams...near the stream, seeing perfection...What a life this is...aj
*2x10 joists, 16" o.c., footings no more than 6' apart double 2x8 beam, footings minimum 10" diameter at base and all is good in the world. Ohh, and if you run your decking diagonally the decking springs less. Consider using full width decking if concerned with feel....Ohh and blocking mid span....LI smell clam chowder....Looking around....
*OK, MattG, and Mike Smith come here and toe the line. I have just one question.... You two were the only to have responded, (kicked out a recommendation), when Anderson posted. Soooooooo.... Which wonna youse guys is a gal ????And don't try squirming out of this, Anderson wouldn't lie !!!!
*Hello Phillip-I made a bet with myself this morning and I win. Mike Smith came through and made me a prophet. (The guy is everywhere. With sound advise.)Anyway, with your deck design I'm kinda like Mike- more is better. It is very conceivable to see a very high concentrated load on a deck. Nothing kills a summer bbq like a collasping deck with thirty of your closest friends on it. ("closest friends" AKA the plaintiff) The 2x10 joists @ 16" o.c. supported by double 2x12 girder w/1/2" thru bolts at each post- 2 per connection, one post every 6' o.c. I would go with min. 12" dia. footing posts to rest on min. 8" poured concrete, top of footer 6" below local frost line. I like western cypress for decking- doesn't check or split much, easy to mill, seems to hold up better than redwood or cedar.
*OK Luka:Ya got me. I wear a dress. And that ohhhh so silky underwear. BTW, I'd like you to go on the Springer show with me! Got something I gotta reveal to you!PS:I don't think anyone should be giving recommendations for footing sizes without knowing what the soil characteristics are that Phillip is dealing with. Also, floor bounce - it's a subjective thing, but personally I can't stand it when I walk across a floor and have things on a table rattle!
*Can't argue with you about the footing recommendations Matt. Short sighted of me...
*I built a deck roughly the same size, 12x24, on a hillside; 0 to 7 ft in 12 feet of distance; I built with 2x8 16oc, on 3 doubled up 2x10 4ft apart, 18 inches of overhang, 2x6 decking (the owners like that!)...it hasn`t moved yet, and with the crowds they had on it so far it ain`t moving still!mc
*Mike:Having trouble getting a mental image of your deck support: "on 3 doubled up 2x10 4ft apart, 18 inches of overhang,"??? Are you saying that there are 3 girders 4' apart? What is the largest clear span of the 2x8 joists?
*the 2x8 joists frame was sitting on 4 beams made out of 2 2x10s, those beams were actually about 45inches apart and from the last one out, the overhang was about 18 inches. The deck was free standing.
*Wow! I guess that is a pretty stiff deck.
*How high is this puppy?You need to consider all of the elements, base, posts and beams as well as joists. The decking is minor once you figure out the big stuff. The taller the deck the stronger it should be. Failures at heights can be serious. Have we talked post sizes yet? 4x4, 6x6 or the infamous 4x6? Bigger posts will reduce deflection. Over six feet high? think about moving up from 4x4s. The greater your span between posts "tributary load area" you will probably need to upgrade to 6x6 posts. Concrete to be 10 inch minimum dia. for 6x6, 12 inch preferred. Eight and ten inch for 4x4. Again what is soil type? Since one side of the deck is on a ledger board, bracing may be needed, depending on deck height. Good solid anchors needed on ledger. Use thru bolts, 1/2" preferred, no lag screws. Also, how will you fasten beams to posts. Notched or placed on top of post is best since beam rests on post, bolted depends on shear strength of bolts If you haven't figured it out yet, I like to build to 60#. 40# is acceptable by a number of codes but 60# will give you a stronger "less bouncy" deck. The difference is a perception of quality. Shaky decks feel cheap.
*STIFF DECK! I said I have a STIFF DECK!!!
*You better watch how loud you say that, CLS may want to try her new recipe.View Image
*Philip,One thing not mentioned is how to attach the ledger board to the house. Or really how not to attach the ledger to the house. I usually pull off the siding where the board will lay, then run flashing up under the siding to below the beam. I then lag the ledger into the band joist and/or studs. Here's the important thing, I shim the ledger off the house with sch.40 drainpipe cut to 1" pieces. I center the shims around the bolts. You can hold them in place with a galv. roofing nail or two while placing the beam. It helps to premark and predrill the beam and the house. If you have a pnue. wrench all the better. Most of the decks I have replaced have had a catastrophic failure at the ledger from rot.(Rotting not only the beam but the house.) Shimming it out allows air behind the beam and thus no rot.I haven't done the math but I'd go with the 2"x10"s too. It's comforting to not feel like your walking on the moon.David Taylor
*I shim out the ledger with verticle strips of 1x3 pressure treated or cedar. Angle-cut or round over the top of the shims for water run-off. Don't skip this step or you'll face eventual water damage as David said.jim
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looking for online deck designing
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DIYonline
*Sam:18' is i way too long for a double 2x10 girder (beam). 2x12s wouldn't get it either. Think steel!Also, with that kind of height, you are going to need some kind of diagional bracing, knee braces, etc.
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I'm designing a new deck; basically 14' x 25' - fastened on one 25' side to a ledger on the house with the other three sides free-standing - Support on the free-side will be 12' from the house w/ a 24" o'hang. I'm getting conflicting info from various sources (on-line design sites & local builders) re: joist & beam size. I intend to use 2 x 10 PT pine joists on a doubled 2 x 10 beam - I'm not afraid of 'overbuilding' but am being told that 2 x 8 joists w/more support posts is the ay to go? Can anyone give me a little direction based on experience?
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Thanks Matt, I expected this to be an impossible situation with 2x lumber. am