I want to build a 16ft wide x 12ft deep deck along one side of house, with beam running parallel to house and 12ft joists extending from ledger on hangers. Would like to cantilever front edge a couple feet or so.
Can somebody recommend good material sizing? I like to overbuild things a bit so nice and solid.
Post size/spacing?
Joist size / spacing?
Beam size?
Beam at 10ft, w/2 ft cantilever okay? Bouncy?
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Replies
Not sure where you live so I'll put up some numbers how I would erect such a structure in my fine state.
Posts 4x6 minimum, buried to frost depth 48", and three total. One on each end and one in the middle.
Precast cookies 5,000 psi, in the bottom of each hole for the post to set on. I use 50 lbs. a sq ft. as a number for loading. Snow, people and all. Can get quite heavy.
2-2x12 for the beam.
2x10 framing, 16 OC joists, ledger.
And your 10' with a 2' cantileiver is fine. I do it all the time.
You're allowed to sink the posts in the ground?
Around here, we have to pour concrete piers 3' deep, and use anchor bases to hold the post.
It's interesting to see the diferences in building techniques in different parts of the country.
Yes we are allowed to bury the posts.
I have never been a a big fan of concrete piers with a post riding on top. Acts like a knuckle.
But I guess it works on light poles and bases. Maybe I need to go back to the bat cave and rethink this.
PS - I think they do that on light poles to meke them break away when a car hits them.
Sounds good. What's a precast cookie? I can guess but have never seen or heard of one... What size do they come in? Roughly how much do they cost? Why do they provide a real advantage?
I think he means these http://www.bigfootsystems.com/ This is one of several companies that make them. It has a larger foot print allowing it to carry more weight and be a better more stable footing. Any lumber yard carries them or can get them and I know HD sells them in my area.
The Bigfoot is just a form for a footing. I believe Stilletto was refering to an actual pre-cast concrete footing that you literally just drop in the hole and set your post on.View Image
Winner, winner, chicken dinner. Instant footing.
LOL.... you been watching too much Sportscenter.View Image
Thanks. Never seen those before.That would never pass around here, right?
Edited 5/23/2007 9:54 pm ET by DDay
I don't live in a high wind zone like you fellers do. BTW all my decks are still standing after the last hurricane we had in Michigan. :)
Our biggest concern is frost here.
No worries Stilletto.... different methods for different parts of the country is all. Here in MA we still have our own building code. I get away with stuff that'd probably make those West Coast boys cry.View Image
You don't have to get away with anything to make the west coast guys cry, they do it automatically. LOL
I was giving you guys a hard time that's all.
Not much for wind around here. On the cape you get some good winds in the winter storms but that's only a few times a winter. We have not had a hurricane up here since 1992 or so. They keep saying were going to get a Cat 4 one of these days but those moron weather pimps also pump every snow storm to death and always miss.
Why won't they allow you to bury the posts?
Rot? I can see the reasoning for easy replacement. Wind? Maybe, I don't know.
You guys pour sono tubes and use base plates there on your decks?
Rot I presume. Yeah, we do the sonotube w/ base plate thing. I usually use a 1/2" by 6" expanding wedge anchor (like a RedHead) to attach the base to the crete. Then the base has nail holes for the post. Funny thing is.... we're not required to do anything special at the top.... attaching the beam to the posts. I see them just toe-nailed together all the time. Go figure.View Image
Cookies are round, precast concrete. They are 4" thick and come in alot of diameters. I usually use the 16" size. Amost like an instant footing.
I'd have to check the latest receipt to get you an exact number.
I really like them, you are ready to start building as soon as they hit the bottom of the hole. They spread the weight out over it's entire width.
It's alot better than mixing concrete, putting your posts in and nailing all sorts 2x's to it at ground level so you can build on it right away.
I'll get the $$ tommorrow when I dig the receipt out of the truck.
You don't need to look up the price. I was just curious. They don't sell 'em around here so it doesn't really matter, although if they were available I'd use them. So, I guess the 5000 PSI concrete facilitates the 4" thickness. I'm guessing one of these 16" cookies weighs around 75#s. Interesting...
Thanks. Pretty much confirms my intuition although here (PNW) need to go with concrete footings.
How would cost/stability compare with 2x8s, 12" O.C.? Not sure what decking material I'm going to use. Sounds like some of composites might benefit from closer spacing.
Edited 5/24/2007 1:51 pm ET by jcharbonneau
Cost wise I couldn't tell you the difference in your area.
I wouldn't go with 2x8's in the span situation you have brewing.
Think of having alot of people on that deck, a few extra dollars in materials is worth it. But I don't know how much snow you get in the winter either.
The joist spacing is a concern if you are running the deck boards at a 45 deg. I like this appearance and elliminates the need for wind shear support.
The span ends up @22" for a 45 on 16oc. This can be a problem with 5/4" decking and most compostes, but I guess you said the boards are parrallel to the house.16" on center should be okay.
Remember to subtract a few inches on the length off the deck. This allows you to trim a 16' off after installed, over hanging both ends. No seams and the ends turn out better. If you plan on seams remember to bring the first joist in 3/4", and the last one in as well
I'll back up Stilletto here. Three footings (four wouldn't be crazy though), 2x10's at 16" OC, 10' spanning w/ 2' cantilever, but I'd change the beam to a trip 2x10 on 4x6's. I try to avoid PT 2x12 as much as possible because it always seems to cup on me.
For posts I like 4x6's up to 6' or so. For posts longer than 6' I like 6x6's.
I know Stilletto is a good builder, but his buried posts wouldn't pass inspection where I am. We need a concrete footing down 4' with a base bolted to the concrete. It's just a regional thing so be sure and check out your local codes.
Also, through bolt your ledger to your rim joist if you have access. If not, try Ledger Lok brand screws instead of lags. They have greater shear and withdrawal resistance than 1/2" lags and are super easy to install.
Don't forget to flash and counterflash the ledger......one of the most important, yet frequently missed, details of your whole deck.
I second Diesel Pig's motion for ledger locks. I use them on my decks as well.
Ledger does concern me a little. Rim joist I'll be fastening to runs parallel to joists so not sure how secure. Old house so probably only toenailed to sill plate which isn't bolted to foundation. Any thoughts? Saw article in FH where they basically built deck freestanding with posts and beam next to foundation. Seems kind of sensible (eliminates whole flashing issue) but more digging and messing around too?