Hello deckmiesters and other interested individuals
I’m building a deck–a simple square one 139″ square.
Attached is a birdseye view of my initial post and “joist” (hope that’s the right word when building decks) layout.
The posts will be 4×4 pt set 24″ in from the corners (blue squares)
2 x 8 pt lumber will be attached (black lines)
then a 2x8pt joist system will be placed on top.
I have a few questions which I could probably find out from a book but I thought what the hell maybe someone is up for the challenge.
1. This question concerns the span that the black 2 x 8 will cover –I figured it to be 80″ is that too much for a 2 x 8 — if it is then I will add an additional post.
2. This question is similar and is in regards to the red joist system- the span to cover is about 75″ — too far if so then I’ll have to add an additional line of posts.
I guess the issue is sort of apparent — my initial and uneducated plan calls for only four posts–if I have to add posts then the next logical number seems to be having nine posts–which is not a big deal–but is twice as much work, so if I don’t have to do it then I won’t.
The deck will be attached to the house via lag bolts and a pergola will be above the deck supported by 4 x4 that will attach to the four outside posts.
other pertinent info:
this is a deck I’m building on my house
I live in Atlanta GA
any deck advice would be appreciated
cje
Replies
CJE- 1. Yes, you can span 8' with a 2'x 8' Doug fir joist, I would recommend a 4 x 8 for your two beam runs instead of 2 x 8. A double 2 x anything for a beam run is just too cheesy for me.
2. Again, yes you will be fine with an 8' span on 2 x 8 joists
If you are only going out 12' I would use 2 x 10 joist fastened to a 2 x 10 ledger fastened to the house, with only one beam run 10' out from the house.
Now you only have two footings to dig at 10' foot span for 4x10 beam.
The Pergola, now that is another story. That should stand alone. By that I mean it should not be held up by the deck. The posts for the pergola should go through the deck to their own footings.
Hope this helps,
Bob
"Rather be a hammer than a nail"
Pro-Dek,
Two things:
1. Depending on locale, a 4x beam might not be available. I don't recall ever seeing anything PT that is wider than 6" in 4x form. It seems that East of the Mississippi, double 2x's are standard fare. I wish we could get 4x's, but to my knowledge that's not practical.
2. What do you think about the posts being 2' from the band joist? Is that too much for a 8" beam?
Jon Blakemore
I guess your right Jon - We do take ALOT for granted here in the Northwest.Treated 4x 6-8-10-and 12 are readily available here. If you have to use 2x material for supports on each side of a post, I would at least upsize to 2x10 and notch the post on each side to support the weight. Having all your deck weight resting on two thru Bolts is a bad idea.
2. 24" is quite a bit of canterlever for 8" I would probably only go 16" making the span 9'4" which would work for a 10' span from the house. Bob
"Rather be a hammer than a nail"
Pro-Dek
Thanks for the advice and suggestions - most interesting and I'll probably use them--love the idea of only having to do two holes--although I'll have to do the pergola ones as well--no problemo.
How about a follow up question:
I've seen two ways to do footings--one way is dig the hole place the post in it - level etc and then back fill with concrete.
The other way is to dig the hole pour with concrete-set a bre-built concrete footing -level -then attach post via light gauge steel connection.
What are the pro and cons of each system?
thanks for your time
cje
Take what you want, leave the rest
I'm not familiar with the ground conditions in Atlanta, but around here our soil is more rock than dirt.
We normally dig a hole 2'x2'x8"deep, put one bag of pre-mix in dry, place a pier block with an adjustable saddle on top of that, then put another bag of pre-mix around that. Then we just hose it down.
Your pergola supports should be in 2x2x12 with an elevated post support placed in the pre-mixed concrete filled hole. Bob
"Rather be a hammer than a nail"
Pro-Bob,
I been watchin that hammer and nail for a while and you know what?
That Hammer never misses!!
Sinks that nail every time with just one hit!
That must take a lot of practice.
TDo not try this at home!
I am a trained professional!
I can get 6x6 and 8x8 pt up to 16 ft from one of my local lumber yards. Couple of thought for Pro Deck: a minor point, but you stated that the Doug fir joists would work...I bet they don't sell a lot of Doug fir in Georgia. Also, wouldn't it be better to have all four posts so the deck is totally self-supporting? Fastening to the house ledger for lateral support would be ok, but why take a chance or a poor connection. As to the pergola...depending on the total height involved, would it be acceptable to run the deck posts continuously all the way up to become the pergola posts? Or would you still use separate posts for each?
I agree w/Pro Deck for the most part but definitly use suano tubes and mix the concrete in the wheel borrow before putting it in the ground. As far as finding out exactly how far lumber will span, you can always call the local lumber yard(usually they have that info).
I would do it with just two posts and one girder on top of them (if your joists run parallel to the house it will be two posts w/two girders, one each running from house to 24" past post.).
As far as your girder material goes using two 2x whatevers is fine as long as you nail them together w/3 or 4 16's every 16'' or so and bear them on top of your posts, not on the sides, as in your drawing.
However you do it - enjoy!
Edited 12/6/2002 7:21:50 PM ET by headcheese
Whats the height of the deck from the ground?My opinion if a decks height is over 5 or 6 feet a 4x4 is to small and looks like a pencil stuck in the ground holding up a deck. not to mention the way they sway around when supported by 2 long 4x4's, I would use 2 cedar 6x6's with 2x10x10'pt joists and with 2x10 ledger use joist hangers at the ledger and the rim, bridge the joistst at mid span, Iam in kansas we make our post holes 3ft deep 9'' round use a sono tube 1 piece rebar center of concrete use an adjustable post base or the cast aluminum post base stand off (Simpson strong tie)I would make the deck and pergola posts continuous 6x6 cedar let in the 2 2x10 beams fasten with through bolts or lags 1/2'' and you might use a (forget what their called somebody help me out) its a steel ring used between the lumber and increases the bearing ability etc. of the connection. use continuous 5/4 decking material screwed with 2'' galv or coated screws I like the Deck Guard screws they have a nice phillips+square drive head and a bit is in the box with the screws. The cross beam for the pergola and railing will tie the whole structure together.Ive attached a photo of a deck (the deck also has a cedar 1x2 frame and latice skirting)that my business partner and I built for a customer.Good luck whichever way you go,becareful and have fun!
Okay you hit a home run for me --thepictures are fantastic--lets face it someone can write and write and write about how to do something but as soon as you show a picture it becomes so much more useful. I really..really appreciate you taking the time to post these--just looking at how you did stuff answers alot of questions for me. I've never even touched a deck before--I've done alot of other stuff from complete kitchen remodel, bath remodel, moving bearing walls (I like to think that I'm a little above the average home DIY'er)--point is thanks for the photo's--I feel like I really know how to proceed now--thanks.
cjeTake what you want, leave the rest